U.S. patent application number 16/068505 was filed with the patent office on 2019-01-10 for catalyst compositions and process for direct production of hydrogen cyanide in an acrylonitrile reactor feed stream.
This patent application is currently assigned to Ascend Performance Materials Operations LLC. The applicant listed for this patent is Ascend Performance Materials Operations LLC. Invention is credited to Yawu T. Chi, Ranjeeth Reddy Kalluri, Mikhail Khramov, Marty Alan Lail, Scott G. Moffatt, Bruce F. Monzyk, Maruthi Sreekanth Pavani, Soundar Ramchandran.
Application Number | 20190009252 16/068505 |
Document ID | / |
Family ID | 59274467 |
Filed Date | 2019-01-10 |
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United States Patent
Application |
20190009252 |
Kind Code |
A1 |
Chi; Yawu T. ; et
al. |
January 10, 2019 |
CATALYST COMPOSITIONS AND PROCESS FOR DIRECT PRODUCTION OF HYDROGEN
CYANIDE IN AN ACRYLONITRILE REACTOR FEED STREAM
Abstract
The present invention relates to catalyst compositions
containing a mixed oxide catalyst of formula (I) or formula (II) as
described herein, their preparation, and their use in a process for
ammoxidation of various organic compounds to their corresponding
nitriles and to the selective catalytic oxidation of excess
NH.sub.3 present in effluent gas streams to N.sub.2 and/or
NO.sub.x.
Inventors: |
Chi; Yawu T.; (Sugar Land,
TX) ; Moffatt; Scott G.; (Pearland, TX) ;
Khramov; Mikhail; (Pensacola, FL) ; Kalluri; Ranjeeth
Reddy; (Friendswood, TX) ; Monzyk; Bruce F.;
(Town Creek, AL) ; Ramchandran; Soundar;
(Friendswood, TX) ; Lail; Marty Alan; (Raleigh,
NC) ; Pavani; Maruthi Sreekanth; (Kavali,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ascend Performance Materials Operations LLC |
Houston |
TX |
US |
|
|
Assignee: |
Ascend Performance Materials
Operations LLC
Houston
TX
|
Family ID: |
59274467 |
Appl. No.: |
16/068505 |
Filed: |
January 9, 2017 |
PCT Filed: |
January 9, 2017 |
PCT NO: |
PCT/US2017/012671 |
371 Date: |
July 6, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62276861 |
Jan 9, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 35/1009 20130101;
B01D 2255/20769 20130101; B01J 2523/18 20130101; B01J 2523/19
20130101; B01D 2255/2065 20130101; B01D 2255/2098 20130101; B01D
2255/1026 20130101; B01J 23/8898 20130101; B01J 2523/824 20130101;
B01D 2255/2047 20130101; B01D 2255/20784 20130101; B01J 21/04
20130101; B01D 2255/20746 20130101; B01J 2523/74 20130101; B01D
53/94 20130101; B01D 2251/102 20130101; B01J 21/066 20130101; B01J
37/04 20130101; B01D 2255/209 20130101; B01D 2255/40 20130101; B01D
2255/9202 20130101; B01J 2523/67 20130101; B01J 2523/828 20130101;
C07C 253/24 20130101; B01D 53/8634 20130101; B01D 2255/20761
20130101; B01D 2255/9207 20130101; B01J 2523/72 20130101; B01J
23/002 20130101; B01J 2523/69 20130101; B01J 21/08 20130101; B01D
2255/20792 20130101; B01D 2257/406 20130101; B01J 2523/68 20130101;
B01J 37/031 20130101; B01J 23/8993 20130101; B01J 2523/44 20130101;
B01D 2255/2096 20130101; B01J 21/063 20130101; B01J 35/1019
20130101; B01J 37/0215 20130101; B01D 2255/20738 20130101; B01D
2255/2073 20130101; B01D 2255/20753 20130101; B01J 23/8876
20130101; B01J 23/8878 20130101; B01J 2523/00 20130101; B01J
2523/00 20130101; B01J 2523/22 20130101; B01J 2523/375 20130101;
B01J 2523/53 20130101; B01J 2523/54 20130101; B01J 2523/67
20130101; B01J 2523/68 20130101; B01J 2523/821 20130101; B01J
2523/842 20130101; B01J 2523/845 20130101; B01J 2523/00 20130101;
B01J 2523/24 20130101; B01J 2523/3712 20130101; B01J 2523/53
20130101; B01J 2523/54 20130101; B01J 2523/67 20130101; B01J
2523/68 20130101; B01J 2523/821 20130101; B01J 2523/842 20130101;
B01J 2523/847 20130101; B01J 2523/00 20130101; B01J 2523/22
20130101; B01J 2523/3712 20130101; B01J 2523/54 20130101; B01J
2523/67 20130101; B01J 2523/68 20130101; B01J 2523/74 20130101;
B01J 2523/821 20130101; B01J 2523/842 20130101; B01J 2523/00
20130101; B01J 2523/22 20130101; B01J 2523/3712 20130101; B01J
2523/54 20130101; B01J 2523/67 20130101; B01J 2523/68 20130101;
B01J 2523/72 20130101; B01J 2523/842 20130101; B01J 2523/00
20130101; B01J 2523/22 20130101; B01J 2523/48 20130101; B01J
2523/53 20130101; B01J 2523/54 20130101; B01J 2523/67 20130101;
B01J 2523/68 20130101; B01J 2523/74 20130101; B01J 2523/821
20130101; B01J 2523/842 20130101; B01J 2523/847 20130101; B01J
2523/00 20130101; B01J 2523/27 20130101; B01J 2523/375 20130101;
B01J 2523/43 20130101; B01J 2523/53 20130101; B01J 2523/54
20130101; B01J 2523/67 20130101; B01J 2523/68 20130101; B01J
2523/72 20130101; B01J 2523/842 20130101; B01J 2523/847 20130101;
B01J 2523/00 20130101; B01J 2523/17 20130101; B01J 2523/22
20130101; B01J 2523/375 20130101; B01J 2523/54 20130101; B01J
2523/67 20130101; B01J 2523/68 20130101; B01J 2523/72 20130101;
B01J 2523/74 20130101; B01J 2523/842 20130101; B01J 2523/847
20130101; B01J 2523/00 20130101; B01J 2523/27 20130101; B01J
2523/375 20130101; B01J 2523/54 20130101; B01J 2523/67 20130101;
B01J 2523/68 20130101; B01J 2523/74 20130101; B01J 2523/842
20130101; B01J 2523/845 20130101; B01J 2523/847 20130101; B01J
2523/00 20130101; B01J 2523/17 20130101; B01J 2523/22 20130101;
B01J 2523/27 20130101; B01J 2523/54 20130101; B01J 2523/67
20130101; B01J 2523/68 20130101; B01J 2523/72 20130101; B01J
2523/842 20130101; B01J 2523/845 20130101 |
International
Class: |
B01J 23/00 20060101
B01J023/00; B01J 23/887 20060101 B01J023/887; B01J 23/889 20060101
B01J023/889; B01J 23/89 20060101 B01J023/89; B01J 21/04 20060101
B01J021/04; B01J 21/06 20060101 B01J021/06; B01J 21/08 20060101
B01J021/08; B01J 35/10 20060101 B01J035/10; B01J 37/03 20060101
B01J037/03; B01J 37/04 20060101 B01J037/04; B01J 37/02 20060101
B01J037/02; B01D 53/86 20060101 B01D053/86; C07C 253/24 20060101
C07C253/24 |
Claims
1. A catalyst composition comprising a mixed oxide catalyst of
formula (I) or (II):
Mo.sub.12X.sup.1.sub.aX.sup.2.sub.bX.sup.3.sub.cX.sup.4.sub.dX.sup.5.sub.-
eX.sup.6.sub.fO.sub.h (I)
FeMo.sub.iCr.sub.jBi.sub.kM.sub.mN.sub.nQ.sub.qX.sub.xY.sub.yO.sub.r
(II) wherein in the formula (I): X.sup.1 is Cr and/or W; X.sup.2 is
Bi, Sb, As, P, and/or a rare earth metal; X.sup.3 is Fe, Ru, and/or
Os; X.sup.4 is Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, and/or
Pb; X.sup.5 is Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn,
Re, V, Nb, Ta, Se, and/or Te; X.sup.6 is an alkaline earth metal
and/or an alkali metal; 0.ltoreq.a.ltoreq.5;
0.03.ltoreq.b.ltoreq.25; 0.ltoreq.c.ltoreq.20;
0.ltoreq.d.ltoreq.200; 0.ltoreq.e.ltoreq.8; 0.ltoreq.f.ltoreq.3;
and h is the number of oxygen atoms required to satisfy the valence
requirements of the component elements other than oxygen present in
formula (I), where 1.ltoreq.c+d+e+f.ltoreq.200;
0.ltoreq.e+f.ltoreq.8; and wherein in the formula (II): M is Ce
and/or Sb; N is La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
Lu, Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, Pb, P, and/or As; Q
is W, Ru, and/or Os; X is Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn,
Cd, Hg, Mn, Re, V, Nb, Ta, Se, and/or Te; Y is an alkaline earth
metal and/or an alkali metal; 0.2.ltoreq.i.ltoreq.100;
0.ltoreq.j.ltoreq.2; 0.ltoreq.k.ltoreq.2; 0.05.ltoreq.m.ltoreq.10;
0.ltoreq.n.ltoreq.200; 0.ltoreq.q.ltoreq.8; 0.ltoreq.x.ltoreq.30;
0.ltoreq.y.ltoreq.8; j and k<i; m>j; and r is the number of
oxygen atoms required to satisfy the valence requirements of the
component elements other than oxygen present in formula (II),
wherein: 4.ltoreq.m+n+q+x+y.ltoreq.200; 0.ltoreq.q+x+y.ltoreq.30;
and wherein the catalyst composition has a surface area of from 2
to 500 m.sup.2/g as determined by the Brunauer-Emmett-Teller (BET)
method.
2. The catalyst composition according to claim 1, wherein in the
formula (I): 0.ltoreq.a.ltoreq.3; 0.04.ltoreq.b.ltoreq.20;
0.ltoreq.c.ltoreq.15; 0.ltoreq.d.ltoreq.175; 0.ltoreq.e.ltoreq.5;
0.ltoreq.f.ltoreq.2; 3.ltoreq.c+d+e+f.ltoreq.175; and
0.ltoreq.e+f.ltoreq.5, and wherein in the formula (II):
0.3.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.1.5;
0.ltoreq.k.ltoreq.1.5; 0.1 m.ltoreq.8; 0.ltoreq.n.ltoreq.100;
0.ltoreq.q.ltoreq.3; 0.ltoreq.x.ltoreq.10; 0.ltoreq.y.ltoreq.3; j
and k<i; m>j; 4.5.ltoreq.m+n+q+x+y.ltoreq.100;
0.ltoreq.q+x+y.ltoreq.10.
3. The catalyst composition according to claim 2, wherein in the
formula (I): 0.ltoreq.a.ltoreq.1; 0.05.ltoreq.b.ltoreq.15;
0.1.ltoreq.c.ltoreq.9; 0.ltoreq.d.ltoreq.150; 0.ltoreq.e.ltoreq.2;
0.ltoreq.f.ltoreq.1, 5.ltoreq.c+d+e+f.ltoreq.150; and
0.ltoreq.e+f.ltoreq.2, and wherein in the formula (II):
0.5.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.0.5;
0.ltoreq.k.ltoreq.0.75; 0.2.ltoreq.m.ltoreq.5;
0.ltoreq.n.ltoreq.60; 0.ltoreq.q.ltoreq.1.5; 0.ltoreq.x.ltoreq.5;
0.ltoreq.y.ltoreq.2; j and k<i; m>j;
5.ltoreq.m+n+q+x+y.ltoreq.60; and 0.ltoreq.q+x+y.ltoreq.7.5.
4. The catalyst composition according to claim 1, wherein the
catalyst composition consists of a mixed oxide catalyst of the
formula (I) or (II).
5. The catalyst composition according to claim 1, wherein the
catalyst composition further comprises a support selected from the
group consisting of silica, zirconia, titania, alumina and mixtures
thereof.
6.-10. (canceled)
11. A process for preparing the catalyst composition of formula (I)
according to claim 1, the process comprising: (i) preparing a first
mixture comprising: source compounds of elements Cr and/or W in an
aqueous solution; full or partial amounts of elements Bi, Sb, As,
P, and/or a rare earth metal; full or partial amounts of elements
Fe, Ru, and/or Os, an alkali metal element and/or an alkaline earth
metal element; full or partial amounts of elements Co, Rh, Ir, Ni,
Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn, Re, V, Nb, Ta, Se, Te, Hf, B,
Ga, In, TI, Ge, Sn, and/or Pb; (ii) preparing a second mixture
comprising source compounds of at least one or more of full or
partial amounts of Mo, Si, Ti, Zr, and Al in an aqueous solution,
and of remaining amounts of the step (i) elements required in the
mixed oxide catalysts of formula (I) and formula (II); (iii) adding
the first mixture to the second mixture under conditions sufficient
to react and form precipitate slurry, with optional use of a basic
compound to adjust pH; (iv) filtering the precipitate slurry; (v)
optionally mixing the precipitate slurry with the source compounds
of any remaining amounts of the step (ii) Mo, Si, Ti, Zr and Al
elements required in the mixed oxide catalysts of formula (I) and
formula (II) to form a catalyst precursor; and (vi) drying and
calcining the catalyst precursor to form the catalyst
composition.
12. A process for preparing the catalyst composition of formula
(II) according to claim 1, the process comprising: (i) preparing a
first mixture comprising: source compounds of elements Fe, Cr, and
Bi in an aqueous solution; full or partial amounts of elements of
at least t one or more of Ce and/or Sb; full or partial amounts of
elements La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,
Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, Pb, P and/or As, W, Ru
and/or Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn, Re,
V, Nb, Ta, Se and/or Te; and an alkaline earth metal and/or an
alkali metal; (ii) preparing a second mixture comprising source
compounds of at least one or more of full or partial amounts of Mo,
Si, Ti, Zr, and Al in an aqueous solution, and of remaining amounts
of step (i) elements required in the mixed oxide catalysts of
formula (I) and formula (II); (iii) adding the first mixture to the
second mixture under conditions sufficient to react and form a
precipitate slurry, with optional use of a basic compound to adjust
pH; (iv) filtering the precipitate slurry; (v) optionally mixing
the precipitate slurry with the source compounds of any remaining
amounts of the step (ii) Mo, Si, Ti, Zr and Al elements required in
the mixed oxide catalysts of formula (I) and formula (II) to form a
catalyst precursor; and (vi) drying and calcining the catalyst
precursor to form the catalyst composition.
13.-16. (canceled)
17. A process of preparing a catalyst composition coated onto a
monolith support, comprising coating the monolith support with the
catalyst composition according to claim 1 by dip coating, wash
coating, curtain coating, vacuum coating, chemical vapor
deposition, sputter coating or mixtures thereof.
18. The process according to claim 11, wherein the calcining step
occurs at a temperature from about 300.degree. C. to about
900.degree. C. in the presence of air, an inert gas, carbon
dioxide, steam or mixtures thereof.
19. A process for ammoxidation of an alcohol or an
alcohol-containing mixture, a nitrile or a nitrile-containing
mixture, a ketone or a ketone-containing mixture, an aldehyde or an
aldehyde-containing containing mixture, a carboxylic acid or a
carboxylic acid-containing mixture, an ester or an ester-containing
mixture, an ether or an ether-containing mixture, or mixtures
thereof comprising reacting the alcohol or the alcohol-containing
mixture, the nitrile or the nitrile-containing mixture, the ketone
or the ketone-containing mixture, the aldehyde or the
aldehyde-containing containing mixture, the carboxylic acid or the
carboxylic acid-containing mixture, the ester or the
ester-containing mixture, the ether or the ether-containing
mixture, or mixtures thereof with NH.sub.3 and O.sub.2 in the
presence of a catalyst composition to provide HCN and/or ACN and/or
corresponding nitriles, wherein the catalyst composition comprises
a mixed oxide catalyst of formula (I) or (II):
Mo.sub.12X.sup.1.sub.aX.sup.2.sub.bX.sup.3.sub.cX.sup.4.sub.dX.sup.5.sub.-
eX.sup.6.sub.fO.sub.h (I)
FeMo.sub.iCr.sub.jBi.sub.kM.sub.mN.sub.nQ.sub.qX.sub.xY.sub.yO.sub.r
(II) wherein in the formula (I): X.sup.1 is Cr and/or W; X.sup.2 is
Bi, Sb, As, P, and/or a rare earth metal; X.sup.3 is Fe, Ru, and/or
Os; X.sup.4 is Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, and/or
Pb; X.sup.5 is Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn,
Re, V, Nb, Ta, Se, and/or Te; X.sup.6 is an alkaline earth metal
and/or an alkali metal; 0.ltoreq.a.ltoreq.5;
0.03.ltoreq.b.ltoreq.25; 0.ltoreq.c.ltoreq.20;
0.ltoreq.d.ltoreq.200; 0.ltoreq.e.ltoreq.8; 0.ltoreq.f.ltoreq.3;
and h is the number of oxygen atoms required to satisfy the valence
requirements of the component elements other than oxygen present in
formula (I), where 1.ltoreq.c+d+e+f.ltoreq.200;
0.ltoreq.e+f.ltoreq.8; and wherein in the formula (II): M is Ce
and/or Sb; N is La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
Lu, Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, Pb, P, and/or As; Q
is W, Ru and/or Os; X is Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn,
Cd, Hg, Mn, Re, V, Nb, Ta, Se and/or Te; Y is an alkaline earth
metal and/or an alkali metal; 0.2.ltoreq.i.ltoreq.100;
0.ltoreq.j.ltoreq.2; 0.ltoreq.k.ltoreq.2; 0.05.ltoreq.m.ltoreq.10;
0.ltoreq.n.ltoreq.200; 0.ltoreq.q.ltoreq.8; 0.ltoreq.x.ltoreq.30;
0.ltoreq.y.ltoreq.8; j and k<i; m>j; and r is the number of
oxygen atoms required to satisfy the valence requirements of the
component elements other than oxygen present in formula (II), where
4.ltoreq.m+n+q+x+y.ltoreq.200; 0.ltoreq.q+x+y.ltoreq.30; and
wherein the catalyst composition has a surface area of from 2 to
500 m.sup.2/g as determined by the Brunauer-Emmett-Teller (BET)
method.
20. The process according to claim 19, wherein in the formula (I):
0.ltoreq.a.ltoreq.3; 0.04.ltoreq.b.ltoreq.20; 0.ltoreq.c.ltoreq.15;
0.ltoreq.d.ltoreq.175; 0.ltoreq.e.ltoreq.5; 0.ltoreq.f.ltoreq.2;
3.ltoreq.c+d+e+f.ltoreq.175; and 0.ltoreq.e+f.ltoreq.5, and wherein
in the formula (II): 0.3.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.1.5;
0.ltoreq.k.ltoreq.1.5; 0.1.ltoreq.m.ltoreq.8;
0.ltoreq.n.ltoreq.100; 0.ltoreq.q.ltoreq.3; 0.ltoreq.x.ltoreq.10;
0.ltoreq.y.ltoreq.3; j and k<i; m>j;
4.5.ltoreq.m+n+q+x+y.ltoreq.100; 0.ltoreq.q+x+y.ltoreq.10.
21. The process according to claim 19, wherein in the formula (I):
0.ltoreq.a.ltoreq.1; 0.05.ltoreq.b.ltoreq.15;
0.1.ltoreq.c.ltoreq.9; 0.ltoreq.d.ltoreq.150; 0.ltoreq.e.ltoreq.2;
0.ltoreq.f.ltoreq.1, 5.ltoreq.c+d+e+f.ltoreq.150; and
0.ltoreq.e+f.ltoreq.2, and wherein in the formula (II):
0.5.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.0.5;
0.ltoreq.k.ltoreq.0.75; 0.2.ltoreq.m.ltoreq.5;
0.ltoreq.n.ltoreq.60; 0.ltoreq.q.ltoreq.1.5; 0.ltoreq.x.ltoreq.5;
0.ltoreq.y.ltoreq.2; j and k<i; m>j;
5.ltoreq.m+n+q+x+y.ltoreq.60; and 0.ltoreq.q+x+y.ltoreq.7.5.
22. The process according to claim 19, wherein the catalyst
composition consists of a mixed oxide catalyst of the formula (I)
or (II).
23.-37. (canceled)
38. The process according to claim 19, wherein the ammoxidation is
of CH.sub.3OH, EtOH, propanol or mixtures thereof.
39. The process according to claim 19, wherein the ammoxidation is
of propionitrile, acetonitrile, methacrylonitrile or mixtures
thereof.
40. The process according to claim 19, wherein the ammoxidation is
of acetone; methyl ethyl ketone; methyl esters of acetic, formic,
and propionic acid; dimethyl esters of oxalic acid; acetals of
formaldehyde and acetaldehyde; acrolein; methyl, ethyl, and propyl
ethanoates; dimethyl ether, diethyl ether, methyl ethyl ether,
MTBE; or mixtures thereof.
41.-49. (canceled)
50. A process for selective catalytic oxidation (SCO) of NH.sub.3
to N.sub.2 and/or NO.sub.x in the presence of O.sub.2 comprising
reacting the NH.sub.3 with the O.sub.2 in the presence of the
catalyst composition according to claim 1.
51. The process according to claim 50, wherein the NH.sub.3 and
O.sub.2 are present in an effluent stream of a primary AN reactor
or an ammoxidation reactor.
52.-53. (canceled)
54. The process according to claim 50, wherein the catalyst
composition comprises the mixed oxide catalyst of formula (I).
55. The process according to claim 50, wherein the catalyst
composition comprises the mixed oxide catalyst of formula (II).
56. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] Hydrogen cyanide (HCN) and acetonitrile (ACN) have long been
recognized as un-optimized co-products in the manufacture of
acrylonitrile (AN) by the SOHIO process (U.S. Pat. No. 2,904,580),
and related synthetic routes that utilize propylene/propane, oxygen
(O.sub.2), and ammonia (NH.sub.3) as feed stocks in an ammoxidation
reaction conducted in catalytic fluidized bed reactors. In view of
the growing demand for HCN in the past decade and with continued
growth predicted in the foreseeable future due to the conversion of
HCN to a number of industrial products (e.g., sodium and potassium
cyanides for the mining industry, chelating agents, etc.), the
demand for acetonitrile also continues to grow in pharmaceutical
and in analytical applications. HCN and ACN formation may be
expressed by the following reactions in the propylene
(CH.sub.2.dbd.CH--CH.sub.3) ammoxidation process:
CH.sub.2.dbd.CH--CH.sub.3+3NH.sub.3+3O.sub.2.fwdarw.3HCN+6H.sub.2O
(1)
2CH.sub.2.dbd.CH--CH.sub.3+3NH.sub.3+3O.sub.2.fwdarw.3CH.sub.3--CN+6H.su-
b.2O (2)
[0002] Methods for co-producing HCN from AN reactors or for
producing HCN directly from low carbon alcohols are well known. The
amount of HCN produced as a by-product in propylene ammoxidation is
linked to the amount of produced AN. When HCN demand exceeds the
production of HCN in a propylene ammoxidation process, methanol
(CH.sub.3OH) can be fed with propylene into the ammoxidation
reactors, where it reacts with NH.sub.3 and O.sub.2 in the presence
of an AN catalyst to produce HCN as follows:
CH.sub.3OH+NH.sub.3+O.sub.2.fwdarw.HCN+3H.sub.2O (3)
[0003] However, AN catalysts and reactors are optimized for
propylene ammoxidation rather than for CH.sub.3OH ammoxidation to
produce HCN. Also, the introduction of CH.sub.3OH into the
propylene ammoxidation feed may have the adverse effect of reducing
the lifetime of the catalyst. These methods typically involve, for
example, the addition (such as by injection) of CH.sub.3OH or other
alcohols into an AN reactor; the use of on-purpose
CH.sub.3OH-to-HCN reactors; the addition of a set of internals
within the AN reactor (U.S. Pat. No. 6,716,405); CH.sub.3OH-to-HCN
process patents, especially as they relate to AN plants; processes
for eliminating waste material during the manufacture of AN (U.S.
Pat. Nos. 5,288,473; 5,457,723; 5,466,857; and 5,288,473); and
processes for the recovery and recycling of NH.sub.3 from a vapor
stream (U.S. Pat. No. 7,326,391).
[0004] The injection of CH.sub.3OH or ethanol (EtOH) into a fluid
bed reactor to produce HCN or ACN is well known and minimizes the
amount of unconverted NH.sub.3 residing in the effluent streams. In
addition, the conventional art discloses that CH.sub.3OH or EtOH
may be introduced into a fluid bed reactor to increase the amount
of co-product (HCN or ACN) while manufacturing AN. For example,
U.S. Pat. Nos. 3,911,089; 4,485,079; and 5,288,473 are directed to
the ammoxidation of CH.sub.3OH to produce HCN by injection of the
CH.sub.3OH into a fluid bed reactor containing an ammoxidation
catalyst suitable for the manufacture of acrylonitrile. Each of
these patents teaches that CH.sub.3OH injection can be made
simultaneously in AN reactors.
[0005] Japanese Patent Applications 74-87,474; 79-08, 655; and
78-35,232 relate to methods of increasing HCN yield during the
manufacture of AN. Japanese Patent Application 2[1990]-38,333 is
directed to improving ACN yields by injecting acetone and/or EtOH
during the manufacture of AN. Each of these disclosures is
concerned with the production of either additional HCN or ACN
within an AN reactor, and are therefore limited by the AN reaction
catalyst, the reactor design and/or operational constraints (e.g.,
excess O.sub.2 requirements, optimum feed ratios, etc.).
[0006] Metal oxide catalysts have been disclosed as generating HCN
from CH.sub.3OH ammoxidation, such as Mo--P oxides (U.S. Pat. No.
2,746,843); Fe--Mo oxides (U.S. Pat. No. 4,425,260); and Mn--P
oxides (U.S. Pat. No. 4,457,905). The activities and selectivities
of binary metal oxides have been enhanced by the addition of
various elements such as those disclosed in U.S. Pat. No. 4,485,079
(promoted Mo--Bi--Ce oxides); 4,511,548 (promoted Sb--P oxides);
4,981,830 (promoted Fe--Sb--P oxides); 5,094,990 (promoted
Fe--Sb--P oxides); 5,158,787 (promoted Fe--Cu--Sb--P oxides);
5,976,482 (promoted Fe--Sb--P--V oxides); and 6,057,471 (promoted
Mo oxides and promoted Sb oxides). U.S. Pat. No. 7,763,225
discloses a Mn--P oxide catalyst promoted with K, Ca, Mo, Zn, Fe or
mixtures thereof that exhibit a higher HCN yield from CH.sub.3OH
ammoxidation.
[0007] The catalysts used for co-producing HCN from propylene
ammoxidation include promoted U--Sb oxides such as disclosed in
U.S. Pat. Nos. 3,816,596; 4,000,178; 4,018,712; 4,487,850;
4,547,484; and 6,916,763; and in WO 2000/072962. Promoted Bi--Mo
oxides are disclosed in U.S. Pat. Nos. 5,093,299; 5,212,137;
5,658,842; 5,834,394; and 8,455,838. Promoted Sb--Fe oxides are
disclosed in U.S. Pat. No. 5,094,990.
[0008] U.S. Pat. No. 4,040,978 discloses a multi-step process for
the production of an ammoxidation catalyst that includes
individually forming the molybdate of cobalt, nickel, iron and an
oxide or salt of bismuth; followed by forming an aqueous slurry of
the individual molybdates and bismuth oxide or a salt thereof;
separating the solid phase from the slurry; adding silica support
material to the slurry resulting from the combined solid phases
(precipitates), and calcining the spray-dried slurry to form the
catalyst.
[0009] U.S. Pat. No. 5,780,664 discloses an ammoxidation catalyst
which has been prepared by providing a slurry containing a silica
sol and sources of component metallic elements, spray-drying the
slurry, followed by calcination. U.S. Pat. No. 6,916,763 discloses
a process for preparing a catalyst for the oxidation and
ammoxidation of olefins by contacting an aqueous Sb.sub.2O.sub.3
slurry with HNO.sub.3 and one or more metal compounds to form a
first mixture which is substantially free of silica sol; heating
and drying the first mixture to form a solid product; and then
calcining the solid product to form the catalyst.
[0010] There have been continuous advances in CH.sub.3OH and
propylene ammoxidation catalysts in the past forty years,
particularly with respect to improvements in activity, selectivity,
and stability. A low activity catalyst requires a temperature
increase to achieve an acceptable conversion, which undesirably
decreases the selectivity of the target products and adversely
reduces catalyst stability. Catalyst activity typically declines
over the operating reaction time, eventually requiring partial or
full replacement of the catalyst with fresh or regenerated
catalyst. In a commercial operation, an increase in temperature
within the operation window is also required to compensate for the
catalyst deactivation. Thus, there is a need for an
activity-improved catalyst which is capable of reaction at a lower
operating temperature, which exhibits higher selectivity, a higher
product yield and greater catalyst stability which allows for a
wider temperature window in which a commercial plant can operate,
and also for longer times between costly maintenance and catalyst
replacement. In a particular application, a need exists for a
"HCN-on-purpose" efficient catalyst that can utilize an AN reactor
effluent stream as an NH.sub.3 and O.sub.2 source and that employs
a low carbon number primary alcohol feed to selectively produce HCN
in a commercially acceptable yield.
[0011] The commercial utility of a catalytic process is highly
dependent upon the cost of the catalyst and the associated chemical
conversion process, the conversion of the reactant(s), the yield of
the desired product(s), and the stability of the catalyst during
commercial operation. An activity-improved catalyst that exhibits
higher yields of the desired product(s) can minimize downstream
process operations, including the need for product purification and
the handling of large recycle streams. Therefore, there exists a
strong need to develop not only a new or improved catalyst and a
method of making the catalyst for HCN and/or ACN production, but
also a more effective means for reusing and/or removing unconverted
NH.sub.3 in an AN reactor effluent stream. The unconverted NH.sub.3
present in an ammoxidation reactor effluent stream may originate
from ammoxidation of methane, methanol, propane, propylene,
isobutane, isobutylene, their derivatives, or mixtures thereof, to
form HCN, acrylonitrile and methacrylonitrile, respectively. The
same or different catalyst may also convert the unreacted methane,
methanol, propylene, propane, isobutylene, isobutane, their
derivatives, or mixtures thereof from a first or precedent reactor
and unconverted NH.sub.3 and/or O.sub.2 present in an ammoxidation
reactor effluent stream to HCN, acrylonitrile and
methacrylonitrile, respectively.
[0012] Selective catalytic oxidation (SCO) of ammonia (NH.sub.3) to
nitrogen (N.sub.2) has been employed as a means for ammonia removal
in the presence of a catalyst. Noble metal catalysts allow the
oxidation of NH.sub.3 to N.sub.2 to occur at low temperatures which
avoids or minimizes the undesired high temperature formation of
NOx. U.S. Pat. Nos. 8,007,735 and 7,410,626 disclose noble metals
disposed on a support or substrate as catalysts for this purpose. A
need exists for a less expensive non-noble metal catalyst, such as
a mixed metal oxide catalyst, for selective oxidization of NH.sub.3
to N.sub.2 in the presence of O.sub.2 at low temperatures.
SUMMARY OF THE INVENTION
[0013] An aspect of the present invention generally relates to a
novel catalyst composition comprising or consisting of a mixed
oxide catalyst of formula (I) or (II) or a mixture thereof, its
preparation, and its use in the ammoxidation of alcohols, nitriles,
ketones, aldehydes, carboxylic acids, esters, ethers, or mixtures
thereof to HCN or to the corresponding nitriles, and also in the
selective catalytic oxidation (SCO) of NH.sub.3 to N.sub.2.
[0014] Another aspect of the present invention is directed to a
process of adding alcohols, such as CH.sub.3OH and/or EtOH, into an
AN reactor effluent stream containing unconverted NH.sub.3 and
O.sub.2 to produce HCN under ammoxidation conditions using the
catalyst compositions of the invention as a means for removing the
unconverted NH.sub.3 from the AN production process.
[0015] An exemplary embodiment of the present invention minimizes
any potentially negative impact associated with an AN reactor
design and its operational constraints by specifically utilizing a
dedicated secondary reactor placed downstream of the primary AN
reactor, where the features of the secondary reactor are
specifically tailored for HCN and/or ACN production and/or NH.sub.3
elimination using the catalyst compositions of the present
invention.
[0016] In an exemplary embodiment, the secondary reactor utilizes a
fixed bed type catalyst composition of a desired shape (e.g.,
crushed particles, spheres, cylindrical extrudates, monoliths, and
the like). In another exemplary embodiment, the catalyst
compositions of the invention are coated onto a secondary monolith
substrate or directly extruded into monolith blocks.
[0017] An aspect of the invention is a catalyst composition
comprising or consisting of a mixed oxide catalyst composition
represented by the following formula (I) or (II):
Mo.sub.12X.sup.1.sub.aX.sup.2.sub.bX.sup.3.sub.cX.sup.4.sub.dX.sup.5.sub-
.eX.sup.6.sub.fO.sub.h (I)
FeMo.sub.iCr.sub.jBi.sub.kM.sub.mN.sub.nQ.sub.qX.sub.xY.sub.yO.sub.r
(II) [0018] or a mixture of (I) and (II), [0019] wherein in formula
(I): [0020] X.sup.1 is Cr and/or W; [0021] X.sup.2 is Bi, Sb, As,
P, and/or a rare earth metal; [0022] X.sup.3 is Fe, Ru, and/or Os;
[0023] X.sup.4 is Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, and/or
Pb; [0024] X.sup.5 is Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Hg, Mn, Re, V, Nb, Ta, Se, and/or Te; [0025] X.sup.6 is an alkali
earth metal and/or an alkali metal; and [0026] where the subscripts
a, b, c, d, e, f and h are, respectively, the atomic ratios of
X.sup.1, X.sup.2, X.sup.3, X.sup.4, [0027] X.sup.5, X.sup.6
elements and oxygen (O), relative to 12 atoms of molybdenum (Mo),
where [0028] 0.ltoreq.a.ltoreq.5; [0029] 0.03.ltoreq.b.ltoreq.25;
[0030] 0.ltoreq.c.ltoreq.20; [0031] 0.ltoreq.d.ltoreq.200; [0032]
0.ltoreq.e.ltoreq.8; [0033] 0.ltoreq.f.ltoreq.3; and [0034] h is
the number of oxygen atoms required to satisfy the valence
requirements of the [0035] component elements other than oxygen
present in formula (I), where [0036] 1.ltoreq.c+d+e+f.ltoreq.200;
[0037] 0.ltoreq.e+f.ltoreq.8; and [0038] wherein in formula (II):
[0039] M is Ce and/or Sb; [0040] N is La, Pr, Nd, Pm, Sm, Eu, Gd,
Tb, Dy, Ho, Er, Tm, Yb, Lu, Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge,
Sn, Pb, P, and/or As; [0041] Q is W, Ru, and/or Os; [0042] X is Co,
Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn, Re, V, Nb, Ta, Se,
and/or Te; [0043] Y is an alkali earth metal and/or an alkali
metal; and [0044] the subscripts i, j, k, m, n, q, x, y and r are,
respectively, the atomic ratios of molybdenum (Mo), chromium (Cr),
bismuth (Bi), M, N, Q, X, Y and oxygen (O), relative to 1 atom of
iron (Fe), and where [0045] 0.2.ltoreq.i.ltoreq.100; [0046]
0.ltoreq.j.ltoreq.2; [0047] j<i; [0048] 0.ltoreq.k.ltoreq.2;
[0049] k<i; [0050] 0.05.ltoreq.m.ltoreq.10; [0051] m>j;
[0052] 0.ltoreq.n.ltoreq.200; [0053] 0.ltoreq.q.ltoreq.8; [0054]
0.ltoreq.x.ltoreq.30; [0055] 0.ltoreq.y.ltoreq.8; and [0056] r is
the number of oxygen atoms required to satisfy the valence
requirements of the component elements other than oxygen present in
formula (II), where [0057] 4.ltoreq.m+n+q+x+y.ltoreq.200; [0058]
0.ltoreq.q+x+y.ltoreq.30, [0059] wherein the catalyst has a surface
area of from 2 to 500 m.sup.2/g as determined by the
Brunauer-Emmett-Teller (BET) method.
[0060] In an exemplary embodiment of the above described catalytic
compositions, 0.ltoreq.a.ltoreq.3; 0.04.ltoreq.b.ltoreq.20;
0.ltoreq.c.ltoreq.15; 0.ltoreq.d.ltoreq.175; 0.ltoreq.e.ltoreq.5;
0.ltoreq.f.ltoreq.2; 3.ltoreq.c+d+e+f.ltoreq.175; and
0.ltoreq.e+f.ltoreq.5 for formula (I); and 0.3.ltoreq.i.ltoreq.50;
0 j 1.5; j<i; 0.ltoreq.k.ltoreq.1.5; k<i,
0.1.ltoreq.m.ltoreq.8; m>j; 0 n.ltoreq.100; 0.ltoreq.q.ltoreq.3;
0.ltoreq.x.ltoreq.10; 0.ltoreq.y.ltoreq.3;
4.5.ltoreq.m+n+q+x+y.ltoreq.100; and 0.ltoreq.q+x+y.ltoreq.10 for
formula (II).
[0061] In another exemplary embodiment of the above described
catalytic compositions, 0.ltoreq.a.ltoreq.1;
0.05.ltoreq.b.ltoreq.15; 0.1.ltoreq.c 9; 0.ltoreq.d.ltoreq.150;
0.ltoreq.e.ltoreq.2; 0.ltoreq.f.ltoreq.1;
5.ltoreq.c+d+e+f.ltoreq.150; and 0.ltoreq.e+f.ltoreq.2 for formula
(I); and 0.5.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.0.5; j<i;
0.ltoreq.k.ltoreq.0.75; k<i; 0.2.ltoreq.m.ltoreq.5; m>j;
0.ltoreq.n.ltoreq.60; 0.ltoreq.q.ltoreq.1.5; 0.ltoreq.x.ltoreq.5;
0.ltoreq.y.ltoreq.2; 5.ltoreq.m+n+q+x+y.ltoreq.60; and
0.ltoreq.q+x+y.ltoreq.7.5 for formula (II).
[0062] In an exemplary embodiment, the catalyst composition
comprises a mixture of the mixed oxide catalysts of formula (I) and
formula (II).
[0063] In an exemplary embodiment, the catalyst composition
consists of a mixture of the mixed oxide catalysts of formula (I)
and formula (II).
[0064] In an exemplary embodiment, the catalyst composition
comprises a mixed oxide catalyst of formula (I).
[0065] In an exemplary embodiment, the catalyst composition
comprises a mixed oxide catalyst of formula (II).
[0066] In an exemplary embodiment, the catalyst composition
consists of a mixed oxide catalyst of formula (I).
[0067] In an exemplary embodiment, the catalyst composition
consists of a mixed oxide catalyst of formula (II).
[0068] In an exemplary embodiment, the catalyst composition of the
present invention can be used in either unsupported (bulk) or
supported form. Suitable supports (also referred to herein as
"carriers") include, but are not limited to, silica, zirconia,
titania, alumina and mixtures thereof. The support may comprise
from 0% up to 99%, such as 10% up to 95%, such as 10% up to 90%,
such as 20% up to 80%, such as 30% up to 80%, such as 40% up to
80%, such as 50% up to 80%, by weight of the catalyst
composition.
[0069] In an exemplary embodiment, the support is colloidal silica
having an average particle size ranging from approximately 2 to
1,000 nm, such as 2 to 900 nm, such as 10 to 700 nm, such as 10 to
500 nm, such as 10 to 300 nm, such as 10 to 200 nm, such as 10 to
100 nm, in diameter.
[0070] In an exemplary embodiment, the catalyst composition of the
present invention can be shaped, with or without an organic or
inorganic binder, into a suitable form that includes, for example,
spheres, granules, pellets, extrudates, cylinders, trilobes,
quadrilobes, ribs, rings, monoliths, wagon wheels, gauzes and
mixtures thereof.
[0071] In various particular embodiments, the molar ratios of Mo/Fe
vary from approximately 50 to 2 and give unexpected results as
evidenced by high HCN yields and CH.sub.3OH conversions.
[0072] In one embodiment, the catalyst composition of the present
invention is coated onto a cordierite monolith. The coating process
parameters, slurry solids content, particle size, pH, viscosity,
and other parameters can be adjusted or optimized as needed to
achieve commercially durable adhesion and a uniform coating. The
catalyst composition is coated onto a monolith structure to give
low backpressure. The catalyst composition can also be loaded onto
one or more desired form of carriers selected from, for example,
spheres, granules, pellets, extrudates, cylinders, trilobes,
quadrilobes, ribs, rings, monoliths, wagon wheels, gauzes and
mixtures thereof. The monolith can be prepared from one or more
materials selected from cordierite, ceramic, metallic, zeolite,
carbides, mullite, alumina, clays or carbon and mixtures thereof.
The monolith preferably comprises one or more materials selected
from cordierite, ceramic, or metallic and mixtures thereof. The
coating may be conducted in a single step or in multiple steps by,
for example, dip coating, wash coating, curtain coating, vacuum
coating, chemical vapor deposition or sputter coating or
combinations thereof.
[0073] Another aspect of the invention is directed to a process for
preparing a catalyst composition comprising or consisting of a
mixed oxide catalyst represented by formula (I) as described
herein, the process comprising: [0074] (i) preparing a first
mixture (mixture A) using source compounds of elements Cr and/or W
in an aqueous solution; full or partial amounts of elements Bi, Sb,
As, P, and/or a rare earth metal; full or partial amounts of
elements Fe, Ru, and/or Os; an alkali metal element and/or an
alkaline earth metal element; full or partial amounts of elements
of Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn, Re, V, Nb,
Ta, Se, Te, Hf, B, Ga, In, TI, Ge, Sn, and/or Pb; [0075] (ii)
preparing a second mixture (mixture B) using source compounds of at
least one or more of full or partial amounts of Mo, Si, Ti, Zr, and
Al in an aqueous solution, and of remaining amounts of the step (i)
elements to meet the above identified catalyst composition; [0076]
(iii) adding the mixture A to the mixture B to react and form a
precipitate slurry, optionally using ammonia or other conventional
base compounds to adjust pH; [0077] (iv) filtering the precipitate
slurry, and optionally mixing the precipitate with the source
compounds of the remaining amounts of the step (ii) Mo, Si, Ti, Zr,
and Al elements to meet the above-identified catalyst composition,
to form a catalyst precursor; and [0078] (v) drying and calcining
the catalyst precursor to form the catalyst composition.
[0079] A further aspect of the invention is directed to a process
for preparing a catalyst composition comprising or consisting of a
mixed oxide catalyst represented by formula (II) as described
herein, the process comprising: [0080] (i) preparing a first
mixture (mixture A) using source compounds of the elements Fe, Cr
and Bi in an aqueous solution; full or partial amounts of at least
one or more of the elements Ce and/or Sb; full or partial amounts
of the elements La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
Lu, Ti, Zr, Hf, B, Al, Ga, In, TI, Si, Ge, Sn, Pb, P and/or As;
full or partial amounts of the elements W, Ru and/or Os; full or
partial amounts of the elements Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au,
Zn, Cd, Hg, Mn, Re, V, Nb, Ta, Se and/or Te; and an alkali metal
and/or an alkaline earth metal; [0081] (ii) preparing a second
mixture (mixture B) using source compounds of at least one or more
of full or partial amounts of Mo, Si, Ti, Zr, and Al in an aqueous
solution, and of remaining amounts of the step (i) elements to meet
the above identified catalyst composition; [0082] (iii) adding the
mixture A to the mixture B to react and form a precipitate slurry,
optionally using ammonia or other conventional base compounds to
adjust pH; [0083] (iv) filtering the precipitate slurry, and
optionally mixing the precipitate with the source compounds of the
remaining amounts of the step (ii) Mo, Si, Ti, Zr, and Al elements
to meet the above-identified catalyst composition, to form a
catalyst precursor; and [0084] (v) drying and calcining the
catalyst precursor to form the catalyst composition.
[0085] In an exemplary embodiment of the process for preparing the
catalyst compositions of the invention, the filtered precipitate
slurry is mixed with the source compounds of any remaining amounts
of the step (ii) Mo, Si, Ti, Zr and Al elements present in the
mixed oxide catalysts of formula (I) and formula (II) to form the
catalyst precursor.
[0086] In another exemplary embodiment of the process for preparing
the catalyst compositions of the invention, the sum of the
quantities of the elements added as "full or partial amounts" and
as "remaining amounts" is equal to the total quantities of the
individual elements present in the catalyst precursor and the final
catalyst composition. The remaining amount is 0 to 100% of the full
amount of the elements present in the final catalyst
compositions.
[0087] In another exemplary embodiment of the process for preparing
the catalyst compositions of the invention, any suitable source
compounds containing more than one of the elements present in the
mixed oxide catalysts of formula (I) and formula (II) can be used,
where all the elements present in the source compounds are elements
present in the final catalyst compositions.
[0088] The catalyst precursor is dried and calcined in air to form
the final (i.e., finished) catalyst composition. Any conventional
drying means can be used, including box drying, spray drying, belt
drying, vacuum drying, hot plate evaporation, rotary evaporation
etc. A preferred drying temperature is between 100.degree. C. and
250.degree. C., such as between 110.degree. C. and 230.degree. C.
Any conventional calcination means can be used, including a box
calciner, rotary calciner, belt calciner, etc. A preferred
calcination temperature is between 300.degree. C. and 900.degree.
C., such as between 450.degree. C. and 700.degree. C., such as
between 450.degree. C. and 550.degree. C. The calcination may be
conducted under various conditions, such as in the presence of air,
an inert gas, carbon dioxide, steam or combinations thereof. In an
exemplary embodiment, the calcining temperatures result in a phase
transformation from a gamma morphology to an alpha or beta form. In
a particular embodiment, the gamma form is more reactive than the
alpha or beta forms.
[0089] The catalyst precursor (before drying and/or after drying),
a partially calcined catalyst, and a fully calcined catalyst can be
applied, loaded, and/or coated onto any other substrates and/or
structured materials, and may also be shaped into a desired form.
In one embodiment, the calcined catalyst is dip-coated onto a
cordierite monolith to give low backpressure.
[0090] Another aspect of the invention is a process of treating
alcohols (especially low carbon alcohols such as methanol, ethanol
and propanol) or alcohol-containing mixtures, or nitriles or
nitrile-containing mixtures, or ketones or ketone-containing
mixtures, or aldehydes or aldehyde-containing mixtures, or
carboxylic acids or carboxylic acid-containing mixtures, or esters
or ester-containing mixtures, or ethers or ether-containing
mixtures or mixtures of any of the foregoing in the presence of the
catalyst compositions of the present invention under ammoxidation
conditions to provide HCN and the corresponding nitriles.
[0091] Another aspect of the invention is a process of injecting
one alcohol or a mixture of alcohols (such as CH.sub.3OH, EtOH,
propanol, butanol, allyl alcohol, phenylmethanol, diphenylmethanol,
and triphenylmethanol), and/or nitriles (such as propionitrile
(PN)) or nitrile-containing mixtures, and/or ketones (such as
acetone) or ketone-containing mixtures, and/or aldehydes (such as
formaldehdyde, acetaldehyde, acrolein) or aldehyde-containing
mixtures, and/or carboxylic acids (such as acetic, formic and
oxalic acids) or carboxylic acid-containing mixtures, and/or esters
(such as methyl or dimethyl or methyl-ethyl ether esters of acetic,
formic and oxalic acids) or ester-containing mixtures, or ethers
(such as dimethyl ether, diethyl ether, and methyl ethyl ether) or
ether-containing mixtures or mixtures of any of the foregoing in
the presence of the catalyst compositions of the present invention
under ammoxidation conditions to provide HCN and/or ACN or other
corresponding nitriles. Other suitable compounds include, but are
not limited to, acetals of formaldehdyde, acetaldehyde or acrolein,
alkene nitriles, aromatic nitriles, polyols (such as ethylene
glycol, propylene glycol or glycerol), trioxane (formaldehyde
trimer) or mixtures of any of the foregoing.
[0092] In an exemplary embodiment of the invention, methanol is
injected into a conventional AN production reactor effluent stream
containing excess unconverted NH.sub.3 and O.sub.2 in the presence
of the catalyst compositions of the present invention under
ammoxidation conditions to produce HCN. FIG. 1 illustrates a
suitable location for "the on-purpose HCN" production reactor (107)
in a conventional AN production process or plant.
[0093] An exemplary embodiment of the invention involves the use of
a dedicated secondary reactor containing a catalyst especially
designed for the generation of additional HCN and nitriles or for
destruction of excess NH.sub.3. This arrangement of a secondary
reactor in combination with a primary AN reactor is desirable
because it yields significantly higher benefits compared to
approaches for improving catalyst efficiency described in the
conventional art. In a particular embodiment, the secondary
reactor/catalyst design employs a catalyst composition of the
present invention. In another embodiment, the catalyst may be any
known ammoxidation catalyst, such as those referenced herein. FIG.
1 illustrates a specific embodiment showing a suitable location for
the secondary reactor (107) in a conventional AN production process
or plant.
[0094] In an exemplary embodiment of the invention, methanol is
injected outside of an AN reactor into an AN reactor effluent
stream containing unconverted ammonia (NH.sub.3) and oxygen
(O.sub.2) with the intent to uncouple conventional co-production of
HCN from AN reactors (propylene ammoxidation process) and
HCN-production from CH.sub.3OH ammoxidation (CH.sub.3OH
ammoxidation process), to produce HCN in the vapor phase under
ammoxidation conditions in the presence of the catalyst
compositions of the present invention and not limited to the excess
O.sub.2 limitations of a first AN reactor.
[0095] Another aspect of the invention is a process for converting
unconverted NH.sub.3 and O.sub.2 present in the ammoxidation
reactor effluent stream to HCN in the presence of the catalyst
compositions of the present invention as a means for NH.sub.3
removal that is superior to the conventional acidic neutralization
of NH.sub.3 required in a downstream operation in an AN and/or
methacrylonitrile production process that is based on the
ammoxidation of propylene, propane, isobutylene, isobutane or
mixtures thereof.
[0096] Another aspect of the invention is a selective catalytic
oxidation (SCO) process which oxidizes and eliminates unconverted
and/or excess NH.sub.3 present in an AN effluent gas stream by
conversion of the NH.sub.3 to N.sub.2 by reaction with excess
O.sub.2 already present in the AN reactor effluent stream, which is
superior compared to conventional NH.sub.3 removal by acidic
neutralization of NH.sub.3 in a downstream operation in an AN
production process.
[0097] In an exemplary embodiment of the invention, methanol is
injected into a conventional AN production reactor effluent stream
containing excess unconverted NH.sub.3, and/or unconverted O.sub.2,
and/or unconverted propylene and/or propane, and/or unconverted
isobutylene and/or isobutane or mixtures of any of the foregoing
from the first or preceding reactor in the presence of the catalyst
compositions of the present invention and/or other suitable known
ammoxidation catalysts to produce HCN, acrylonitrile and
methacrylonitrile, respectively.
[0098] In an exemplary embodiment of the invention, one alcohol or
a mixture of alcohols (such as CH.sub.3OH and/or EtOH), and/or
nitriles (such as propionitrile (PN)), and/or ketones (such as
acetone), or aldehydes or aldehyde-containing mixtures, or
carboxylic acids or carboxylic acid-containing mixtures, or esters
or ester-containing mixtures, or ethers or ethers-containing
mixtures, their derivatives, or mixtures of any of the foregoing
are injected into a reactor effluent stream containing excess
unconverted NH.sub.3, and/or unconverted O.sub.2, and/or
unconverted methane and/or methanol, ethane and/or ethylene and/or
ethanol, propylene and/or propane, and/or unconverted isobutylene
and/or isobutane or mixtures of any of the foregoing from the first
or precedent reactor to produce HCN and/or ACN and/or
acrylonitrile, and/or methacrylonitrile, and/or other corresponding
nitriles in the presence of the catalyst compositions of the
present invention and/or other suitable known ammoxidation
catalysts. Methanol, formaldehyde and dimethyl ether all can be
oxidized to formic acid, suggesting that the reaction products
and/or reactions of these different functional groups (i.e.,
hydroxyl, carbonyl, and ether) are the same or very similar with
respect to oxidation. Ethers and esters both contain an ether
linkage and react similarly, as evidenced by the fact that dimethyl
ether (CH.sub.3--O--CH.sub.3) and methyl methanoate
(H--COO--CH.sub.3) both can be catalytically converted to ethanol
(EtOH). Similarly, alcohols and nitriles can react similarly to
methanol (CH.sub.3OH) and PN. In addition to CH.sub.3OH, ethanol
(EtOH), acetone and PN, other suitable feeds include, but are not
limited to, propanol, butanol, allyl alcohol, phenylmethanol,
diphenylmethanol, triphenylmethanol, acetals of formaldehdyde,
acetaldehyde, acrolein (such as mono acetals and dimethyl acetals),
ketones (such as methyl ethyl ketone, cetyl acetone, cyclohexanone,
methyl isopropyl ketone, methyl isobutyl ketone and
cyclopentanone), aldehydes and dialdehydes (such as formaldehyde,
acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde,
tolualdehyde, furfural, and glyoxal and butanedial), saturated
carboxylic acids and unsaturated carboxylic acids (such as carbonic
acid, formic acid, acetic acid, propionic acid, butyric acid,
valeric acid and hexanoic acid as exemplary of straight-chain,
saturated carboxylic acids; and benzoic acid as exemplary of
aromatic carboxylic acids; and oxalic acid and adipic acid as
representative of dicarboxylic acids), linear and nonlinear esters
(such as dimethyl esters and methyl-ethyl ether esters, and methyl,
ethyl, propyl, butyl, and pentyl methanoates, ethanoates,
propanoates, butanoates, pentanoates, hexanoates, benzoates and
lactates), symmetrical and unsymmetrical ethers (such as dimethyl
ether and diethyl ether, diisopropyl ether, methyl ethyl ether,
methyl tert-butyl ether (MTBE), tert-amyl methyl ether, methyl
sec-butyl ether, methyl phenyl ether, tetrahydrofuran, dioxane,
dicyclopentyl ether, methyl phenyl ether, hydroxymethylfurfural
ethers), alkane nitriles other than PN, alkene nitriles, aromatic
nitriles, polyols (such as methanol polymers, ethylene glycol,
propylene glycols or glycerol), trioxane (formaldehyde trimer),
their derivatives or mixtures of any of the foregoing.
[0099] Another aspect of the invention is a process for the
ammoxidation of an alcohol or alcohol-containing mixture, a nitrile
or nitrile-containing mixture, a ketone or ketone-containing
mixture, an aldehyde or aldehyde-containing containing mixture, a
carboxylic acid or carboxylic acid-containing mixture, an ester or
ester-containing mixture, an ether or ether-containing mixture,
their derivatives or mixtures thereof comprising reacting the
alcohol or alcohol-containing mixture, the nitrile or
nitrile-containing mixture, the ketone or ketone-containing
mixture, the aldehyde or aldehyde-containing containing mixture,
the acid or acid-containing mixture, the ester or ester-containing
mixture, the ether or ether-containing mixture, their derivatives
or mixtures thereof with NH.sub.3 and O.sub.2 in the presence of a
catalyst composition to provide HCN and/or ACN and/or the
corresponding nitriles, wherein the catalyst composition comprises
or consists of a mixed oxide catalyst of formula (I) or (II) or a
mixture thereof.
[0100] In an exemplary embodiment of the process for ammoxidation,
the alcohol is selected from the group consisting of
C.sub.1-C.sub.10 alcohols (such as C.sub.1-C.sub.8 alcohols, such
as C.sub.1-C.sub.6 alcohols, such as C.sub.1-C.sub.4 alcohols),
allyl alcohol, phenylmethanol, diphenylmethanol, and
triphenylmethanol.
[0101] In an exemplary embodiment of the process for ammoxidation,
the alcohol is selected from the group consisting of CH.sub.3OH,
EtOH, propanol, butanol, polyols (such as ethylene glycol,
propylene glycol and glycerol) and mixtures thereof.
[0102] In an exemplary embodiment of the process for ammoxidation,
the nitrile is selected from the group consisting of alkane
nitriles, alkene nitriles, aromatic nitriles and mixtures
thereof.
[0103] In an exemplary embodiment of the process for ammoxidation,
the nitrile is selected from the group consisting of acrylonitrile,
acetonitrile, methacrylonitrile, propionitrile, butanenitrile,
benzonitrile and mixtures thereof.
[0104] In an exemplary embodiment of the process for ammoxidation,
the ketone is selected from the group consisting of saturated
ketones, diketones, unsaturated ketones, cyclic ketones having the
formula (CH.sub.2).sub.nCO, where n=2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12 and 13, and mixtures thereof.
[0105] In a particular embodiment of the process for ammoxidation,
the ketone is selected from the group consisting of acetone, methyl
ethyl ketone, acetyl acetone, cyclohexanone, methyl isopropyl
ketone, methyl isobutyl ketone, and cyclopentanone and mixtures
thereof.
[0106] In an exemplary embodiment of the process for ammoxidation,
the aldehyde is selected from the group consisting of formaldehyde,
acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde,
tolualdehyde, furfural, and glyoxal and butanedial and mixtures
thereof; the carboxylic acid is selected from the group consisting
of carbonic acid, formic acid, acetic acid, propionic acid, butyric
acid, valeric acid, hexanoic acid, benzoic acid, oxalic acid, and
adipic acid and mixtures thereof; the ester is selected from the
group consisting of dimethyl esters and methyl-ethyl ether esters,
and methyl, ethyl, propyl, butyl, and pentyl methanoates,
ethanoates, propanoates, butanoates, pentanoates, hexanoates, and
benzoates and mixtures thereof; and the ether is selected from the
group consisting of dimethyl ether, diethyl ether, diisopropyl
ether, methyl ethyl ether, methyl tert-butyl ether (MTBE),
tert-amyl methyl ether, methyl sec-butyl ether, methyl phenyl
ether, tetrahydrofuran, dioxane, dicyclopentyl ether, methyl phenyl
ether, and hydroxymethylfurfural ethers and mixtures thereof.
[0107] In an exemplary embodiment of the process for ammoxidation,
the source of the O.sub.2 is air or excess unconverted O.sub.2 from
a reactor effluent and the source of the NH.sub.3 is NH.sub.3
independently provided via a feed line or is excess unconverted
NH.sub.3 from a reactor effluent.
[0108] In an exemplary embodiment of the process for ammoxidation,
the reactor effluent is from an ammoxidation process, an oxidation
process or a reduction process.
[0109] In an exemplary embodiment of the process for ammoxidation,
the ammoxidation process is selected from propylene ammoxidation,
isobutylene ammoxidation, propane or isobutane ammoxidation,
alcohol (such as CH.sub.3OH or EtOH or propanol) ammoxidation and
combinations thereof.
[0110] In an exemplary embodiment of the process for ammoxidation,
the ammoxidation is of a nitrile (such as propionitrile (PN),
acetonitrile or methacrylonitrile) or mixtures thereof.
[0111] In an exemplary embodiment of the process for ammoxidation,
the ammoxidation is of acetone; methyl ethyl ketone; methyl esters
of acetic, formic and propionic acid; dimethyl esters of oxalic
acid; acetals of formaldehyde and acetaldehyde; acrolein; methyl,
ethyl, and propyl ethanoates; dimethyl ether, diethyl ether, methyl
ethyl ether, MTBE; or mixtures thereof.
[0112] In an exemplary embodiment of the process for ammoxidation,
the NH.sub.3 and O.sub.2 are present in an AN effluent stream from
a primary AN or ammoxidation reactor, and the alcohol or
alcohol-containing mixture, the nitrile or nitrile-containing
mixture, the ketone or ketone-containing mixture, the aldehyde or
aldehyde-containing containing mixture, the carboxylic acid or
carboxylic acid-containing mixture, the ester or ester-containing
mixture, the ether or ether-containing mixture or mixtures thereof
is reacted with the NH.sub.3 and O.sub.2 in the presence of a
catalyst composition in the secondary reactor downstream of and
connected directly or indirectly to the primary AN reactor outside
of the AN or ammoxidation reactor.
[0113] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition comprises the mixed oxide catalyst of
formula (I).
[0114] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition consists of the mixed oxide catalyst of
formula (I).
[0115] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition comprises the mixed oxide catalyst of
formula (II).
[0116] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition consists of the mixed oxide catalyst of
formula (II).
[0117] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition comprises the mixed oxide catalyst of
formula (I) and the mixed oxide catalyst of formula (II).
[0118] In an exemplary embodiment of the process for ammoxidation,
the catalyst composition consists of the mixed oxide catalyst of
formula (I) and the mixed oxide catalyst of formula (II).
[0119] Another aspect of the invention is a process for the
ammoxidation of an alcohol or alcohol-containing mixture, a nitrile
or nitrile-containing mixture, a ketone or ketone-containing
mixture, an aldehyde or an aldehyde-containing mixture, a
carboxylic acid or a carboxylic acid-containing mixture, an ester
or an ester-containing mixture, an ether or an ether-containing
mixtures, their derivatives, or mixtures of any of the foregoing,
comprising reacting the alcohol or the alcohol-containing mixture,
the nitrile or the nitrile-containing mixture, the ketone or the
ketone-containing mixture, the aldehyde or the aldehyde-containing
mixture, the carboxylic acid or the carboxylic acid-containing
mixture, the ester or the ester-containing mixture, the ether or
the ether-containing mixture, their derivatives, or mixtures of any
of the foregoing with unconverted NH.sub.3 and/or O.sub.2 and/or
unconverted alkanes, alkenes, aromatics, alcohols, aldehydes, their
derivatives, including nitriles, and/or mixtures of any of the
foregoing from the first or preceding reactor to produce HCN,
and/or ACN, and/or acrylonitrile, and/or methacrylonitrile and/or
other corresponding nitriles in the presence of the catalyst
compositions of the present invention and/or other suitable known
ammoxidation catalysts outside of the first or preceding
ammoxidation or AN reactor.
[0120] Another aspect of the invention is a process wherein the
unconverted NH.sub.3 and/or O.sub.2 present in the effluent stream
of the primary ammoxidation reactor reacts with (i) injected
organic (such as hydrocarbon) compounds including alcohols or
alcohol-containing mixtures, nitriles or nitrile-containing
mixtures, ketones or ketone-containing mixtures, aldehydes or
aldehyde-containing mixtures, carboxylic acids or carboxylic
acid-containing mixtures, esters or ester-containing mixtures,
ethers or ether-containing mixtures, their derivatives, or mixtures
thereof and/or (ii) additional components of unconverted alkanes,
alkenes, aromatics, alcohols, aldehydes, their derivatives
(including nitriles) and/or mixtures thereof present in the reactor
effluent of the primary ammoxidation reactor or provided
independently to produce additional HCN and nitrile products in the
presence of the catalyst compositions of the present invention
and/or other suitable ammoxidation catalysts in a secondary reactor
downstream of and connected directly or indirectly to the primary
AN reactor outside of the AN or ammoxidation reactor.
[0121] Another aspect of the invention is a process for the
selective catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the
presence of O.sub.2, comprising reacting the NH.sub.3 with the
O.sub.2 (present in the air or from another source) in the presence
of a SCO catalyst composition.
[0122] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition comprises the mixed oxide
catalyst of formula (I).
[0123] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition consists of the mixed oxide
catalyst of formula (I).
[0124] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition comprises the mixed oxide
catalyst of formula (II).
[0125] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition consists of the mixed oxide
catalyst of formula (II).
[0126] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition comprises the mixed oxide
catalyst of formula (I) and the mixed oxide catalyst of formula
(II).
[0127] In an exemplary embodiment of the process for the selective
catalytic oxidation (SCO) of NH.sub.3 to N.sub.2 in the presence of
O.sub.2, the catalyst composition consists of the mixed oxide
catalyst of formula (I) and the mixed oxide catalyst of formula
(II).
[0128] In an exemplary embodiment, the NH.sub.3 and O.sub.2 are
present in an effluent stream of a primary AN or ammoxidation
reactor.
[0129] In an exemplary embodiment, the NH.sub.3 and O.sub.2 are
reacted in the presence of the catalyst composition in a secondary
reactor downstream of and connected directly or indirectly to the
primary AN or ammoxidation reactor outside of the AN or
ammoxidation reactor.
[0130] In an exemplary embodiment, the selection oxidation catalyst
in the secondary reactor is a conventional selection oxidation
catalyst.
[0131] In an exemplary embodiment of the process for oxidation in a
secondary reactor, the secondary reactor is connected directly to
the primary AN reactor.
[0132] In an exemplary embodiment of the process for oxidation in a
secondary reactor, the secondary reactor is connected indirectly to
the primary AN reactor.
[0133] In an exemplary embodiment, the secondary reactor comprises
a fixed bed reactor where the catalyst is in a form selected from
the group consisting of spheres, granules, pellets, extrudates,
cylinders, trilobes, quadrilobes, ribs, rings, monoliths, wagon
wheels, gauzes and mixtures thereof.
[0134] In an exemplary embodiment, the NH.sub.3 is present in an
NH.sub.3 removal system or process and the O.sub.2 or air is
independently provided via a feed line or is already present with
the NH.sub.3.
[0135] In an exemplary embodiment, the NH.sub.3 to be oxidized to
N.sub.2 and/or NOx for NH.sub.3 removal is present in an exhaust
stream wherein the exhaust gas stream contacts the catalyst of the
present invention in the presence of O.sub.2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0136] The following figures illustrate particular embodiments of
the present invention and are not intended to otherwise limit the
scope of the present invention as described herein.
[0137] FIG. 1 illustrates a suitable location for "the on-purpose
HCN" production reactor (107) in an otherwise conventional AN
production plant.
[0138] FIG. 2 illustrates a plot of test results indicating optimal
catalyst formulations from test data. The figure also shows that
the catalyst compositions appearing at the peak of the data are
particularly effective in converting NH.sub.3 to HCN in high
yield.
[0139] FIG. 3 illustrates the high performance of the ammoxidation
catalyst compositions E1-E12 of the present invention in reacting
with CH.sub.3OH to produce HCN in contrast with comparative
catalysts CE1-CE5, where CE1 is a catalyst of CH.sub.3OH
ammoxidation to produce HCN and CE2 is a catalyst of propylene
ammoxidation.
[0140] FIG. 4 illustrates the test results comparison of CH.sub.3OH
conversion (FIG. 4A) and HCN yield (FIG. 4B) showing that a low
Mo/Fe molar ratio (Mo/Fe=2.17 in Example 11) catalyst can exhibit a
similar performance to that of a high Mo/Fe ratio (Mo/Fe=47.97 in
Example 10) catalyst.
[0141] FIG. 5 illustrates the test results of a temperature
optimization study described in Example 13 using catalyst
composition E1 which shows a maximum yield of HCN unexpectedly
achieved at 425.degree. C.
[0142] FIG. 6 illustrates that catalyst composition E1 provides a
linear conversion fraction of CH.sub.3OH in a direct 1:1 proportion
of NH.sub.3 converted (FIG. 6A); and NH.sub.3 and CH.sub.3OH use
efficiencies (FIG. 6B) at various temperatures.
[0143] FIG. 7 illustrates test results indicating that catalyst
composition E12 achieves an unexpectedly high conversion
(approximately 97% to 100%) of injected CH.sub.3OH into HCN for all
runs performed at 425.degree. C. or above.
[0144] FIG. 8 illustrates the test results of HCN production from
propionitrile (PN) ammoxidation using the catalyst composition
E12.
[0145] FIG. 9 illustrates the test results of HCN and ACN formation
from EtOH ammoxidation using the catalyst composition E12.
[0146] FIG. 10 illustrates the test results of HCN and ACN
formation from acetone ammoxidation using the catalyst composition
E12.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0147] As referred to herein, a "promoter" is one or more
substances added to the catalyst composition, including a support,
to increase the performance (i.e., activity, selectivity, yield,
and stability) as evidenced by increased CH.sub.3OH and NH.sub.3
conversions, HCN yield and/or other co-product yield(s), and
reduced burning of the raw materials or products, including reduced
burning of AN, and/or reduces yields of undesired by-products.
[0148] As referred to herein, "on-purpose HCN" is HCN intentionally
produced to meet specific demand and/or made by using special feed
supply or feed stock. More specifically, in this invention,
"on-purpose HCN" refers to HCN prepared by using unconverted
NH.sub.3 and O.sub.2 in an AN production reactor effluent stream by
injecting CH.sub.3OH outside the main AN reactor.
[0149] As referred to herein, an "effluent stream" is a stream or
flow exiting a chemical reactor. More specifically, in this
invention, "effluent stream" refers to a hot stream existing in an
AN production reactor and containing unconverted NH.sub.3, O.sub.2,
AN product and optionally other by-products.
[0150] As referred to herein, "ammoxidation" is a process for the
production of nitriles using ammonia and oxygen. In the process,
the substrates that react with the NH.sub.3 and O.sub.2 are
typically chemical compounds that include alkenes, alkanes,
alcohols, aldehydes, ketones, esters, ethers and carboxylic acids.
Typically, the compounds react with the NH.sub.3 and O.sub.2 in the
vapor phase in the presence of a catalyst.
[0151] As referred to herein, an "ammoxidation catalyst" is a
catalyst capable of enabling the ammoxidation of chemical compounds
with NH.sub.3 and O.sub.2 to produce nitriles. The catalyst, which
may include a variety of materials, such as metal oxides and
zeolites, may also vary with the feed composition.
[0152] As referred to herein, a "coated monolith" is a monolith
coated or applied with a thin layer of materials on the surface.
The layer thickness varies with application and to-be-coated
material and typically less than 300 microns. A thin layer of the
catalysts of the present invention is coated onto a ceramic
honeycomb monolith as an illustration in this invention.
[0153] As referred to herein, "AN reactor" and/or "AN production
reactor" are reactors to manufacture or produce acrylonitrile (AN)
as a target or key product. In a particular embodiment of the
present invention, the reactor produces AN and/or by-product HCN
from propylene, NH.sub.3, and O.sub.2 and operates at a temperature
range of from 350.degree. C. to 490.degree. C.
[0154] As referred to herein, a "fluidized bed" is a catalytic
reaction zone or bed where the particles of the catalyst
composition and gas mixture are fluidized or behave like a fluid.
In a particular embodiment of the present invention, the gas
mixture passes through the particles of the catalyst composition
(optionally in the form of microspheres) at sufficiently high
velocities to suspend the particles and enable the bed to behave as
a fluid. This fluidized feature typically causes effective mixing,
heat and mass transfer so that it is widely used in the
ammoxidation process which is an exothermic reaction (i.e.,
releases heat).
[0155] As referred to herein, a "fluidized bed reactor" is a type
of reactor in which solids such as the catalyst compositions and/or
reactant particles are fluidized. In general, the reactor contains
features that promote extensive mixing, uniform temperature, and
increased mass-transfer and reaction rates.
[0156] As referred to herein, "DOE" is "design of
experiment"--i.e., a systematic method to determine the
relationship between factors affecting a process and the output of
that process. DOE is used to optimize catalyst design based on
revealed cause-and-effect relationships which shows as a catalyst
composition-and-performance correlation.
[0157] As referred to herein, "unexpected results" refers to
unanticipated positive results, such as a higher or better HCN
yield, CH.sub.3OH conversion, and/or HCN selectivity in an
ammoxidation reaction compared to what is conventionally expected
or normally obtained.
[0158] As referred to herein, the symbol ".ltoreq." includes the
separate and distinct embodiments of "less than" (<) and "equal
to" (=). Similarly, the symbol ".gtoreq." includes the separate and
distinct embodiments of "greater than" (>) and "equal to"
(=).
[0159] As referred to herein, a "rare earth metal" is well known to
be an element from the lanthanide and actinide series of the
periodic table and includes lanthanum, cerium, praseodymium,
neodymium, promethium, samarium, europium, gadolinium, terbium,
dysprosium, holmium, erbium, thulium, ytterbium, lutetium,
actinium, thorium, protactinium, uranium, neptunium, plutonium,
americium, curium, berkelium, californium, einsteinium, fermium,
mendelevium, nobelium and lawrencium.
[0160] As referred to herein, an "alkali metal" is well known to be
an element from Group 1 of the periodic table and includes lithium,
sodium, potassium, rubidium, cesium and francium.
[0161] As referred to herein, an "alkaline earth metal" is well
known to be an element from Group 2 of the periodic table and
includes beryllium, magnesium, calcium, strontium, barium and
radium.
[0162] As referred to herein, the concept of "valence" is well
known and reflects the property of an element that determines the
number of other atoms with which an atom of the element can
combine.
[0163] As referred to herein, the "Brunauer-Emmett-Teller (BET)
method" refers to the use the physical adsorption of gas molecules
on a solid surface as a means for measuring the specific surface
area of a material. Nitrogen is preferably used as an adsorbate.
See, e.g., S.
[0164] J. Gregg and K. S. W. Sing, "Adsorption Surface Area and
Porosity," Academic Press, London, 1967.
[0165] As referred to herein, a C.sub.1-C.sub.10 alcohol includes,
but is not limited to, methanol, ethanol, propanol, isopropanol,
butanol, isobutanol, pentanol, isoamyl alcohol, hexanol, heptanol,
2-ethylhexanol, octanol, nonanol and decanol.
[0166] As referred to herein, "NOx" is a generic expression for
various mono-nitrogen oxides, such as, for example, NO and
NO.sub.2.
[0167] All two-letter abbreviations of the elements of the periodic
table used herein are well known (see, e.g., CRC Handbook of
Chemistry and Physics, 95.sup.th edition, 2014 CRC Press).
[0168] FIG. 2 illustrates a plot of test results for identifying an
optimal catalyst formulation from test data. In the plot, "X
NH.sub.3 Max" refers to "maximum NH.sub.3 conversion", "Y HCN Max"
refers to "maximum HCN yield", and "X CH.sub.3OH Max" refers to
"maximum CH.sub.3OH conversion", respectively. The temperatures of
370.degree. C. and 425.degree. C. represent the reaction
temperatures.
[0169] As described herein the present invention is directed to a
catalyst composition comprising mixed oxides represented by the
formula (I) or (II). In exemplary embodiments of formula (I),
0.ltoreq.a.ltoreq.3; 0.04.ltoreq.b.ltoreq.20; 0.ltoreq.c.ltoreq.15;
0.ltoreq.d.ltoreq.175; 0.ltoreq.e.ltoreq.5; 0.ltoreq.f.ltoreq.2;
3.ltoreq.c+d+e+f.ltoreq.175; and 0.ltoreq.e+f.ltoreq.5. In
exemplary embodiments of formula (II), 0.3.ltoreq.i.ltoreq.50;
0.ltoreq.j.ltoreq.1.5; j<i; 0.ltoreq.k.ltoreq.1.5; k<l;
0.1.ltoreq.m.ltoreq.8; m>j; 0.ltoreq.n.ltoreq.100;
0.ltoreq.q.ltoreq.3; 0.ltoreq.x.ltoreq.10; 0.ltoreq.y.ltoreq.3;
4.5.ltoreq.m+n+q+x+y.ltoreq.100; and 0.ltoreq.q+x+y.ltoreq.10.
[0170] In other exemplary embodiments of formula (I),
0.ltoreq.a.ltoreq.1; 0.05.ltoreq.b.ltoreq.15;
0.1.ltoreq.c.ltoreq.9; 0.ltoreq.d.ltoreq.150; 0.ltoreq.e.ltoreq.2;
0.ltoreq.f.ltoreq.1; 5.ltoreq.c+d+e+f.ltoreq.150; and
0.ltoreq.e+f.ltoreq.2. In other exemplary embodiments of formula
(II), 0.5.ltoreq.i.ltoreq.50; 0.ltoreq.j.ltoreq.0.5; j<i;
0.ltoreq.k.ltoreq.0.75; k<i; 0.2.ltoreq.m.ltoreq.5; m>j;
0.ltoreq.n.ltoreq.60; 0.ltoreq.q.ltoreq.1.5; 0.ltoreq.x.ltoreq.5;
0.ltoreq.y.ltoreq.2; 5.ltoreq.m+n+q+x+y.ltoreq.60; and
0.ltoreq.q+x+y.ltoreq.7.5.
[0171] In a particular embodiment, chromium (Cr) is used in a molar
ratio of Cr/Fe=0.074. The amount of Cr in the catalyst composition
can vary from zero to optimized non-zero levels. Elements in the
same group in the periodic table exhibit similar physical or
chemical characteristics of the outermost electron shells of their
atoms as most chemical properties are dominated by the orbital
location of the outermost electron. As the same VIB group elements
with Cr and molybdenum (Mo), the tungsten (W) can be used as at
various levels. The identified compositions are 0.ltoreq.a.ltoreq.5
in formula (I) or 0.ltoreq.j.ltoreq.2 and j.ltoreq.i in formula
(II).
[0172] In a particular embodiment, bismuth (Bi) is used at a molar
ratio of Bi/Fe=0.13. The amount of Bi in the catalyst composition
can vary from zero to optimized non-zero levels. Similarly, as the
same VA group elements with Bi, the P, As, and Sb can be used at
various levels. Sb is used in multiple embodiments to bring
unexpected results which are related to its different oxidation
states in the resultant catalyst materials in oxides or other
forms, e.g., Sb(3+) in Sb.sub.2O.sub.3, Sb(4+) in Sb.sub.2O.sub.4,
and Sb(5+) in Sb.sub.2O.sub.5. In multiple embodiments, the use of
cerium results in unexpected results which are related to its
reported oxygen storage feature and its different oxidation states
in resulting catalyst materials in oxide form or other forms, e.g.,
Ce(4+) in CeO.sub.2 and Ce(3+) in Ce.sub.2O.sub.3. Similarly to Ce,
other rare earth elements in the same Lanthanide series can be used
as at various levels. Exemplary identified compositions are
0.03.ltoreq.b.ltoreq.25 in formula (I); or 0.2.ltoreq.i.ltoreq.100;
0.ltoreq.k.ltoreq.2; k<i; 0.05.ltoreq.m.ltoreq.10; m>j; and
0.ltoreq.n.ltoreq.200 in formula (II).
[0173] In a particular embodiment, iron (Fe) is used. The amount of
Fe in the catalyst composition can vary from zero to optimized
non-zero levels, or higher. The function of Fe can be related to
its different oxidation states in the resultant catalyst materials
in oxides or other forms, e.g., Fe (3+) in Fe.sub.2O.sub.3; Fe
(3+/2+) in Fe.sub.3O.sub.4; and Fe (2+) in FeO. Similarly, as the
same column elements of VIII group with Fe, Ru and Os can be used
at various levels. For example, Ru is used in multiple embodiments
at a molar ratio of Ru/Fe at 0 and 1.0. The identified compositions
are 0.ltoreq.c.ltoreq.20 in formula (I) or Fe=1 and
0.ltoreq.q.ltoreq.8 in formula (II).
[0174] The catalyst compositions of the present invention can be
used either unsupported (bulk) or supported form. Suitable supports
include but not limited to silica, zirconia, titania, alumina, or
mixtures thereof. The support may comprise as much as 90% in weight
of the catalyst composition. The support may serve multiple roles,
including as support to increase dispersion and reactants
adsorption (i.e., CH.sub.3OH and/or NH.sub.3), and/or as binder to
improve physical strength and catalyst stability. Silica sol is a
preferred supporting material. In multiple embodiments, silica sol
is used at varying molar ratios of Si/Fe from 0 to 38.44. The
silica sol with different particle size and sodium content can be
used, but a silica sol is preferred to have an averaged particle
size of 20 nm with a distribution range from 2 nm to 100 nm and
sodium content less than 1000 ppm, much preferred less than 600
ppm, and even much preferred less than 200 ppm. In one embodiment,
silica powder with a surface area of 730 m.sup.2/g is used and the
resultant catalyst showed unexpected results and a BET surface area
of 359.8 m.sup.2/g.
[0175] In another embodiment, an unsupported catalyst composition
showed unexpected results even when the BET surface area was 9.3
m.sup.2/g. Therefore, the catalyst compositions of the present
invention can be shaped, with and without an organic or inorganic
binder, into an active unsupported catalyst in a suitable form.
[0176] In a particular embodiment, titanium dioxide (TiO.sub.2) in
a powder form is used to give unexpected results at molar ratios of
Ti/Fe at 0 and 14.64. In a particular embodiment, Ce-modified
zirconium (Zr) oxide and/or hydroxide powder and silica sol are
used together at molar ratios of Zr/Fe=3.11 and Si/Fe=14.95 and
give unexpected results. Alumina is used as a binder (embodiment
not included) and the resultant catalyst also give unexpected
results. Similarly, the element of Hf in the same IVB group with Ti
and Zr, the elements of B, Ga, In, and TI in the same IIIA group
with Al, and the elements of Ge, Sn, Pb in the same IVA group with
Si can be used as at various levels and forms. The identified
compositions are 0.ltoreq.d.ltoreq.200 in formula I or
0.ltoreq.n.ltoreq.200 in formula (II). A variety of suitable
supports or modified supports, including silica, in various forms
or shapes can be used, including slurry, sol, gel, powder, bar,
sheet, pellet and mixtures thereof.
[0177] In Ce- and/or Sb-containing embodiments, the presence of Co,
Ni, Zn, Mn, and/or Re yields unexpected results. These elements may
contribute multiple roles, such as forming redox couples from
different oxidation states, increasing reactant (i.e., CH.sub.3OH
and NH.sub.3) adsorption, promoting reactant (i.e., CH.sub.3OH and
NH.sub.3) utilization, enhancing ammoxidation reaction rates,
stabilizing active sites, providing Lewis acids with mild oxidation
capabilities and isoelectronic configurations similar to Fe. In the
presence of Ce and/or Sb, embodiments with combined Co, Ni, Zn, Mn,
and Re molar ratios of from 0 to 6.04 yield unexpected results. It
was observed that in the Ce-free and/or Sb-free embodiments, the
catalyst compositions did not yield unexpected results. Similarly,
Rh, Ir, Pd, Pt, Cu, Ag, Au, Cd, Hg, V, Nb, Ta, Se and/or Te can be
used as at various levels and in various forms. The identified
compositions are 0.ltoreq.e.ltoreq.8 in formula (I) or
0.ltoreq.x.ltoreq.30 in formula (II).
[0178] In Ce- and/or Sb-containing embodiments, Mg yielded
unexpected results at molar ratios of Mg/Fe at 0 and 1.17. The Mg
element may increase binding and stability, decoke, and/or aid
epitaxial lattice matching. In Ce- and/or Sb-free embodiments, the
resulting catalyst compositions did not yield unexpected results
when the molar ratio of Mg/Fe was 0 or 1.17. Similarly, any other
alkaline earth metal, alkali metal and/or mixtures thereof can be
used at various levels and in various forms. The identified
compositions were 0.ltoreq.e.ltoreq.8; 0.ltoreq.f.ltoreq.3;
1.ltoreq.c+d+e+f.ltoreq.200; 0.ltoreq.e+f.ltoreq.8 in formula (I)
or 0.ltoreq.y.ltoreq.8; 4.ltoreq.m+n+q+x+y.ltoreq.200; and
0.ltoreq.q+x+y.ltoreq.30 in formula (II).
[0179] The BET surface area of the catalyst compositions of the
present invention in various exemplary embodiments may vary from
9.0 m.sup.2/g in unsupported catalyst compositions to 360 m.sup.2/g
supported on high surface area silica powder.
[0180] In various exemplary embodiments, the molar ratio of Mo/Fe
was 48:1 and yielded unexpected results. In an exemplary
embodiment, the molar ratio of Mo/Fe was reduced to 2.2:1 and
yielded unexpected results. In another exemplary embodiment, the
molar ratio of Mo/Fe was 2.8:1 and yielded unexpected results.
[0181] In an exemplary embodiment, the catalyst compositions of the
present invention are coated onto a cordierite monolith. The coated
monolith was observed to yield unexpected results. The coating
process parameters, slurry solids content, particle size, pH,
viscosity, and other parameters can be adjusted or optimized as
needed to achieve commercially durable adhesion and uniform
coating. In an exemplary embodiment, the catalyst composition was
coated onto a monolith structure to give low backpressure. The
catalyst compositions can also be loaded onto one or more desired
carrier forms. In an exemplary embodiment, the monolith is made
from one or more materials selected from cordierite, ceramic,
metallic, zeolite, carbides, mullite, alumina, clays or carbon and
mixtures thereof. The monolith is preferably made of from one or
more materials selected from cordierite, ceramic, or metallic and
mixtures thereof.
[0182] As referred to herein, "source compounds" are compounds
which provide one or more of the metals present for the catalyst
compositions of the present invention. As referred to herein, "full
or partial amounts" refer to a full or partial desired quantity of
those elements in the above-described process steps (i) and (ii)
based on the requirements of the identified catalyst composition
formula, suggesting those elements may be used in more than one
step and added more than once. If partial amounts of these elements
are added, suggesting there are remaining amounts of these elements
to be added to meet required quantities of these elements in the
final catalyst composition from above identified catalyst
composition formula. As referred to herein, "remaining amounts of
step (i) elements" refer to those elements used in process step (i)
but their exact quantities are not included based on the above
identified catalyst composition. As referred to herein, "remaining
amounts of step (ii) elements" refer to those elements used in
process step (ii) but their exact quantities are not included based
on the above identified catalyst composition. Therefore, "remaining
amounts of step (i) elements" and "remaining amounts of step (ii)
elements" refer to those quantities of step (i) and step (ii)
elements required in the final catalyst composition which is not
present in the step (i) and step (ii), respectively. As referred to
herein, "remaining amounts of step (i) elements" and "remaining
amounts of step (ii) elements" must be provided and/or added into
the process before the catalyst precursor is dried and calcined to
form the final catalyst composition. Either "full or partial
amounts" or "remaining amounts" can be zero but they cannot both be
zero simultaneously for each individual element of those elements
present in the identified catalyst composition formula. The sum of
the quantities of those individual elements added as "full or
partial amounts" and then added as "remaining amounts" is equal to
the required total quantities of those individual elements present
in the final catalyst composition.
[0183] The remaining amounts of the step (i) elements in the above
step (ii) and the remaining amounts of the step (ii) Mo, Si, Ti,
Zr, and Al elements in the above step (iv) can be zero
simultaneously, suggesting that those elements are added in the
full desired quantity as required by above identified catalyst
composition formula. In an exemplary embodiment, the source
compounds of the Fe, Cr, Co, Gd, Mg, Sb, Ru, and Bi elements are
added at their full desired quantities in the mixture A. The source
compounds of Mo and Si are added at their full desired quantities
in the mixture B. Remaining amounts of the above source compounds
were not used and/or needed to form the catalyst precursor which
were dried and calcined to form the final catalyst composition.
[0184] The source compounds of some elements, especially those
optional elements in steps (i) and (ii) may be added once at the
full amount required in the final catalyst composition but in
different preparation steps. In a particular embodiment, ammonium
perrhenate, represented by the chemical formula NH.sub.4ReO.sub.4
as the source compound of Re, is added in the preparation of the
mixture A at the full amount required in the final catalyst
composition. In another particular embodiment, ammonium perrhenate
as the source compound of Re, is added in the preparation of the
mixture B at the full amount required in the final catalyst
composition. The same amount of NH.sub.4ReO.sub.4 is added
differently in these two embodiments, both of which were observed
to yield unexpected results. The source compounds of Re can be
added in a partial amount in the mixture A and further added at the
remaining amount in the mixture B to meet the full amount present
in the final catalyst composition. Thus, the remaining amount can
be 0-100% of the full amount of those elements required in the
final catalyst depending on what portion of the element has been
previously supplied.
[0185] In an exemplary embodiment, ammonium heptamolybdate (AHM) as
a source compound of Mo was first dissolved in water for
preparation of the mixture B. In a particular embodiment, AHM was
dissolved in water to form a final mixture B which did not contain
supporting materials or any other elements. In an exemplary
embodiment, AHM as the source compound of Mo and silica sol (40%)
as the source compound of Si were added for preparation of the
mixture B where the AHM was first dissolved in water and no
precipitation occurred in the mixture B after both the AHM and
silica sol were added. The order of the addition to the mixture B
was not critical, but in a particular embodiment, it is preferable
that the soluble source compounds or high solubility source
compounds were dissolved in the aqueous solution before the low
solubility source compounds were added.
[0186] In an exemplary embodiment, AHM as the source compound of Mo
was first dissolved in water for preparation of the mixture B, and
then TiO.sub.2 powder as the source compound of Ti was added to the
mixture B which became a particulate slurry after the TiO.sub.2
addition. In another embodiment, AHM as the source compound of Mo
was first dissolved in water for preparation of the mixture B, and
then SiO.sub.2 powder as the source compound of Si was added to the
mixture B which also became a particulate slurry after the
SiO.sub.2 addition. The order of the addition of the source
compound of Mo was not observed to be critical in the catalyst
preparation. The source compound of Mo may be added at any time
during and after the mixture preparation, precipitation, and
filtration, but must be added before the catalyst precursor is
dried. In a particular embodiment, molybdenum trioxide was added
and mixed with the wet precipitate to form the catalyst precursor.
In another particular embodiment, molybdic acid was added and mixed
with the wet precipitate to form the catalyst precursor.
[0187] The pH of the mixture B may vary from 3 to 11 depending upon
the source compounds added and their respective concentrations, but
a neutral or basic mixture B, especially at a pH above 7, is
preferred. A high pH mixture B (i.e., at a pH>9 or higher) can
be added with any conventional inorganic or organic acids, such as,
but not limited to, nitric acid, sulfuric acid, hydrochloric acid,
phosphoric acid, and/or citric acid, formic acid, acetic acid,
lactic acid, succinic acid, glycolic acid, or mixtures thereof to
lower the pH to about 7 to 9. Various conventional bases such as,
but not limited to, ammonia, ammonium carbonate, ammonium
bicarbonate, sodium carbonate, sodium bicarbonate, sodium
hydroxide, potassium carbonate, potassium bicarbonate, potassium
hydroxide, and organic bases such as, but not limited to, urea,
amines and amine salts, or mixtures thereof can be added if needed
to raise the pH to about 7 to 9 when the mixture B has a pH lower
than 7.
[0188] In the process step (i), the source compounds of Fe, Cr, and
Bi elements, and of optional one or more of Sb, Sn, alkali metal,
and alkali earth metal elements, and of optional one or more of
full or partial amounts of rare earth metal, Co, Rh, Ir, Ni, Pd,
Pt, Cu, Ag, Au, Zn, Cd, Hg, Mn, Re, V, Nb, Ta, Se, Te, Hf, B, Ga,
In, TI, Ge, Pb, Ru, Os, W, As, and P elements, were combined in an
aqueous solution to form the mixture A. The resultant mixture A can
be a homogeneous or non-homogeneous mixture, including a solution,
particulate slurry, suspension and colloid. A homogeneous mixture
is preferred but the reaction(s) among the source compounds added
may also form a non-homogeneous mixture depending upon the
properties of each individual source compound added and the
properties of the resultant mixture, such as acidity. An acidic
mixture (i.e., a pH below 7, especially at a pH below 3) is
preferred. A high pH mixture (i.e., a pH>8 or higher) can be
treated with conventional inorganic or organic acids, such as, but
not limited to, nitric acid, sulfuric acid, hydrochloric acid,
phosphoric acid, and/or citric acid to lower the pH to about 3 or
to about 2 or lower. In one embodiment, the source compounds of Fe,
Cr, Co, Gd, Mg, Sb, and Ru in an aqueous solution, and the source
compound of Bi dissolved in a nitric acid and water mixture are
added at fully desired quantities to form the mixture A which is
non-homogeneous.
[0189] After the completion of the preparation of the mixture B as
described above and in process step (ii), the mixture A is added to
the mixture B to react and form a slurry. If needed, a conventional
base can be added to participate and/or assist the precipitation
process. In one embodiment, the mixture A comprising the required
elements added at their fully desired quantities is added to the
mixture B comprising the required elements added at their fully
desired quantities, immediately forming a precipitate upon contact.
In a particular embodiment, aqueous ammonia was added to assist the
precipitation process. The precipitate slurry pH can vary from 5 to
10, such as from 6 to 9, such as from 7 to 8. The temperature can
vary from 4 to 150.degree. C., such as from 10 to 90.degree. C.,
such as from 20 to 70.degree. C. Any conventional mixing mechanism,
devices and/or setup can be used to sufficiently combine and/or mix
the source compounds and precipitate slurry in the solvent in the
mixtures preparation, precipitation, and filtration. A uniform
mixture is desired and/or preferred to lead to a more uniform
catalyst precursor and final catalyst composition.
[0190] In an exemplary embodiment, water is used as a solvent in
the catalyst composition preparation but other solvents can also be
used such as alcohols, organic acids, diluted mineral acids (such
as nitric acid), and mixtures thereof. The aqueous and/or organic
solvents are capable of dissolving at least one of the source
compounds of these elements. In a particular embodiment, water was
used as the solvent for preparing mixtures A and B. The amount of
water used in preparing the mixtures A and B varied with the
solubilities of the source compounds, but should be present in at
least an adequate amount to partially dissolve a portion of the
source compounds to form an agitated mixture. Different ratios of
water to source compounds were used to dissolve the source
compounds and the ratios may be further optimized to facilitate
mixing.
[0191] The source compounds of the elements required for the
catalyst compositions of the present invention may be derived from
any suitable sources, including known inorganic and metallo-organic
materials. For example, the source compound of Mo includes, but is
not limited to, ammonium heptamolybdate (AHM), molybdic acid,
molybdenum dioxide, molybdenum trioxide, molybdenum pentoxide,
molybdenum acetate, and molybdenum chloride. AHM, molybdic acid and
molybdenum trioxide are preferred Mo source compounds in the
present invention. Phosphoric acid (H.sub.3PO.sub.4) is
representative of a source compound of phosphorus (P). Ammonium
phosphomolybdate, represented by the chemical formula
(NH.sub.4).sub.3PMo.sub.12O.sub.40, can provide Mo and P oxides
upon calcination. Therefore, ammonium phosphomolybdate is a
suitable source compound of Mo and P where both Mo and P are
required in the final catalyst composition.
[0192] In exemplary embodiments, the source compounds of Fe, Cr,
and Bi are their corresponding nitrates. Metal salts containing a
nitrate ion are generally soluble in water, so they are preferred
source compounds of those metal elements, especially if they are
readily available. Ferric nitrate, chromium nitrate and bismuth
nitrate are preferred Fe, Cr, and Bi source compounds,
respectively. Other source compound of Fe, Cr, and Bi may include,
but are not limited to, their hydroxides, oxides, chlorides,
sulfates and acetates.
[0193] In exemplary embodiments, the source compounds of Sb and Sn
are antimony trichloride (SbCl.sub.3) and tin chloride pentahydrate
chloride (SnCl.sub.4.5H.sub.2O). SbCl.sub.3 is soluble in an
alcohol such as EtOH but is readily hydrolyzed and precipitates in
water. SnCl.sub.4.5H.sub.2O is readily soluble in water. Other
source compounds of Sb and Sn may include, but are not limited to,
their oxides, chlorides (e.g., SbCl.sub.5 and SnCl.sub.2), acetates
and sulfates.
[0194] In a particular embodiment, the source compound of Mg is
magnesium nitrate. The source compounds of alkali metal and
alkaline earth metal elements include, but are not limited to,
their oxides, hydroxides and salts. The hydroxides, which are
generally water soluble, easily decompose to oxides upon drying or
calcination.
[0195] In a particular embodiment, the source compound of Ce is
cerium nitrate hexahydrate. The source compounds of Ce include, but
are not limited to, cerium nitrate, ceric ammonium nitrate, cerium
oxide, cerium hydroxide, cerium chloride, cerium oxalate, cerium
carbonate, cerium sulfate, cerium acetate, and ceria-doped
material. In an exemplary embodiment, the source compound of Ce was
ceria-doped zirconium hydroxide which simultaneously served as a
source compound of Zr. The remaining rare earth metals may supplied
from any suitable conventional source that can be incorporated into
the catalyst composition. For example, the source compound of Gd is
gadolinium nitrate hexahydrate in a particular embodiment. Both Ce
and Zr in the ceria-doped zirconium hydroxide should be a part of
the total amount of Ce and Zr required in the final catalyst
composition. Similar to ammonium phosphomolybdate and ceria-doped
zirconium hydroxide, any suitable conventional source compounds
containing more than one element listed in the catalyst composition
formula can be used and all the elements present in the source
compounds should be a part of total amount of these elements
required in the final catalyst composition.
[0196] Remaining elements may come from any suitable conventional
source and can be incorporated into a catalyst composition. In
exemplary embodiments, the elements cobalt, nickel, copper, zinc
and manganese may be introduced using their nitrate and/or
carbonate salts. The element ruthenium may be provided from
ruthenium chloride (RuCl.sub.3).
[0197] In a particular embodiment, none of Si, Ti, Zr, Al, or their
mixtures is used as supports or binders in the preparation. As
described previously, the catalyst compositions can be used in an
unsupported (bulk) form or alternatively, in a supported form.
Suitable supports include, but are not limited to, silica,
zirconia, titania, alumina, or mixtures thereof.
[0198] The support may comprise as much as 90% in weight of the
catalyst composition, such as up to 85%, such as up to 80%, such as
up to 75%, such as up to 70%, such as up to 65%, such as up to 60%,
such as up to 50%. In multiple embodiments, silica sol as a support
and/or binder is added in the mixture B preparation before the
precipitation. As described in the above preparation steps
(ii)-(iv), remaining amounts of Mo, Si, Ti, Zr, and Al elements can
be mixed with the precipitate to form the catalyst precursor. The
support may be added any time during and after the mixture
preparation, precipitation, and filtration, but must be added
before the catalyst precursor is being dried. Similarly, any
organic and/or inorganic binders can be added at any time in the
preparation process. The described preparation process provides the
catalyst having unexpected results or performance. All these source
compounds may be combined together via a one-pot synthesis route to
improve the process efficiency as long as the final catalyst
composition satisfies performance requirements.
[0199] The catalyst precursor was dried and calcined in air to form
the final catalyst. Any known drying means can be used, including
box drying, spray drying, belt drying, vacuum drying, hot plate
evaporation, rotary evaporation, etc. In an exemplary embodiment,
the drying temperature was between 100.degree. C. and 250.degree.
C., such as between 110.degree. C. and 230.degree. C. Any known
calcination means can be used, including a box calciner, rotary
calciner, and belt calciner. In an exemplary embodiment, the
calcination temperature is between 300.degree. C. and 700.degree.
C., such as between 450.degree. C. and 600.degree. C.
[0200] The catalyst precursor before and/or after before being
dried, the partially calcined catalyst, and the calcined catalyst
composition can be loaded onto one or more desired forms of
carriers selected from trilobes, quadrilobes, ribs, rings,
monoliths, spheres, granules, pellets, extrudates, cylinder, wagon
wheels, gauzes and mixtures thereof. In one embodiment, the
calcined catalyst composition is dip-coated onto a cordierite
monolith to give a low backpressure. The catalyst precursor and
catalyst composition may be applied, loaded, and/or coated onto
other substrates and/or structured materials, and may be shaped
into a desired form.
[0201] The catalyst compositions of the invention are useful for
catalytic ammoxidation and/or ammonia selective oxidation. In a
particular embodiment, the catalyst composition was produced in a
batch process where the source compounds for the various component
elements are combined via one or more steps to form a catalyst
precursor and eventually the final catalyst composition after
calcination. A continued process and/or processes that use and/or
combine batch process can also be employed to produce the catalyst
compositions of the present invention.
[0202] The catalyst compositions of the present invention may be
prepared by any conventional procedures or methods known to those
skilled in the art, such as, for example, deposition, impregnation,
sol-gel, mechanical milling and/or blending, hydrothermal, and/or
combustion methods. The catalyst or catalyst precursor mixed
compositions of the present invention may also be prepared by
refluxing/boiling a mixture of catalyst precursor metal oxides,
fine metal powders and/or metal precursor salts followed by
recovery, drying and calcination.
[0203] The catalyst compositions of the present invention are
useful in ammoxidation processes of alcohols or alcohol-containing
mixtures, or nitriles or nitrile-containing mixtures, or ketones or
ketone-containing mixtures, or alcohol and nitrile and ketones
co-containing mixtures, to provide HCN and corresponding
nitriles.
[0204] The catalyst compositions of the present invention are
useful in ammoxidation processes of one alcohol or a mixture of
alcohols, such as CH.sub.3OH and/or EtOH, and/or nitriles, such as
propionitrile (PN), and/or ketones, such as acetone, to HCN and/or
ACN and other corresponding nitriles.
[0205] The catalyst compositions of the present invention are
useful in ammoxidation processes of injecting CH.sub.3OH outside of
a conventional AN production reactor, into an AN reactor effluent
stream containing unconverted NH.sub.3 and O.sub.2, to produce HCN
in the vapor phase under ammoxidation conditions that include
conventional conditions.
[0206] The catalyst compositions of the present invention are
useful in ammoxidation processes of injecting CH.sub.3OH outside of
an AN reactor, into the AN reactor effluent stream containing
unconverted NH.sub.3 and O.sub.2, to uncouple the conventional
co-production of HCN from AN reactors (propylene ammoxidation
process) and HCN-production from CH.sub.3OH ammoxidation
(CH.sub.3OH ammoxidation process) to produce HCN and thus not be
limited to the excess O.sub.2 limitations of the first AN
ammoxidation reactor.
[0207] The catalyst compositions of the present invention are
useful in ammoxidation processes which use and convert excess
unconverted NH.sub.3 and O.sub.2 present in an AN reactor effluent
stream to HCN as a more effective means for NH.sub.3 removal than
conventional NH.sub.3 neutralization techniques that require acid
treatment in the downstream operation of the AN production
process.
[0208] The catalyst compositions of the present invention are
useful in SCO processes which oxidize and eliminate unconverted
and/or excess NH.sub.3 to N.sub.2 by reaction with excess O.sub.2
already present in the AN reactor effluent stream, as a more
effective means for NH.sub.3 removal compared to conventional
NH.sub.3 neutralization techniques that require acid treatment in a
downstream operation in the AN production process.
[0209] Conventional conditions for alcohol ammoxidation are also
well known in the prior art as evidenced by U.S. Pat. No.
7,763,225, herein incorporated by reference in its entirety. The
ammoxidation reaction conditions employed in the present invention
are those disclosed in the art for the ammoxidation of CH.sub.3OH,
with typical temperature ranges of 200 to 600.degree. C., with
preferred ranges of from 250 to 550.degree. C., and most preferred
ranges of from 300 to 500.degree. C. The molar ratio of NH.sub.3
and O.sub.2 to CH.sub.3OH or nitrile is approximately
stoichiometric so that most of the reactants will be consumed in
the reaction. Usually, the ratio of NH.sub.3 to CH.sub.3OH or
nitrile is 0.7:1 to 2:1, preferably 0.9:1 to 1.3:1. Use of excess
NH.sub.3 is not desirable because the unconverted NH.sub.3 must be
removed, recovered and recycled, or is wasted. Air is the preferred
O.sub.2 source because it is inexpensive. However, pure O.sub.2 or
O.sub.2-enriched air may also be used. Although fluidized bed
operations may be preferred in various embodiments, the operation
process can occur in a fixed bed, an ebullating bed, or a moving
bed type of operation.
[0210] The catalyst compositions of the present invention are
useful in the preparation of HCN and/or nitriles from ammoxidation
of alcohols, such as CH.sub.3OH and/or EtOH, and/or nitriles,
and/or ketones and provide significantly higher CH.sub.3OH
conversions and HCN yields than comparative catalysts, including
CH.sub.3OH ammoxidation catalysts (i.e., HCN-production from
CH.sub.3OH) and propylene ammoxidation catalysts (i.e.,
conventional HCN co-production from an AN reactor). In an exemplary
embodiment using the catalysts of the present invention, the
CH.sub.3OH conversion increases with temperature, the HCN
selectivity also unexpectedly increases with temperature between,
for example 350.degree. C. and 400.degree. C., and the maximum
yield of HCN is unexpectedly achieved at 425.degree. C. In a
particular embodiment, the catalysts of the present invention
provide a linear conversion fraction of CH.sub.3OH in a direct 1:1
proportion of NH.sub.3 converted and their usage at least 95% at a
temperature of 2425.degree. C. In another embodiment, HCN and ACN
are produced from EtOH ammoxidation, with an increase in both HCN
and nitrile formation. In yet another embodiment, HCN is produced
from propionitrile (PN) ammoxidation. In a further embodiment, HCN
is produced from acetone ammoxidation.
[0211] The present invention is also directed to HCN production by
CH.sub.3OH ammoxidation using unconverted NH.sub.3 present in a
process effluent, such as an ammoxidation reactor effluent. A feed
composition comprising CH.sub.3OH, NH.sub.3, AN, and O.sub.2 is
used to simulate an ammoxidation reactor effluent in which the
NH.sub.3, O.sub.2, and AN represent residual NH.sub.3, residual and
optionally added O.sub.2, and product AN existing from the AN
production reactor and the CH.sub.3OH is injected outside of the AN
reactor. In various exemplary embodiments, the catalysts of the
present invention provide unexpectedly high CH.sub.3OH conversions
and HCN yields in the feed of the simulated AN reactor effluent. In
one embodiment, the CH.sub.3OH conversion and HCN yield were found
to be nearly unchanged before and after AN injection into the
CH.sub.3OH ammoxidation feed comprising CH.sub.3OH, NH.sub.3 and
O.sub.2. AN burning under the tested conditions was found to be
negligible in multiple embodiments. Notably, AN present in the feed
was not significantly oxidized and/or changed in the ammoxidation
process. In yet another embodiment, the catalyst of the present
invention provided close to 100% HCN selectivity at a temperature
between, for example, 325 to 450.degree. C. in the AN-containing
feed.
[0212] The reaction (4) below represents a chemical reaction for
HCN synthesis in the present invention using CH.sub.3OH injection,
with residual NH.sub.3 and O.sub.2 from an AN reactor effluent
stream, which involves the same chemistry as conventional
CH.sub.3OH ammoxidation to HCN as shown in reaction (3). However,
the NH.sub.3 and O.sub.2 in reaction (4) originate from unconverted
or residual NH.sub.3 from an AN reactor effluent. The O.sub.2 in
reaction (4) originates from the AN reactor effluent and can also
be added separately or jointly with CH.sub.3OH injection into the
reactor effluent composition and under process conditions. The
process for HCN production in the present invention is not limited
to the excess O.sub.2 limitations of the first AN ammoxidation
reactor. Reaction (5) illustrates a conventional means of removing
unconverted NH.sub.3 in the conventional ammoxidation process.
Process of the present invention for converting unconverted
NH.sub.3 to HCN:
CH.sub.3OH+NH.sub.3(unconverted)+O.sub.2(unconverted).fwdarw.HCN+3H.sub.-
2O (4)
Conventional process for removing unconverted NH.sub.3 as
(NH.sub.4).sub.2SO.sub.4:
2NH.sub.3(unconverted)+H.sub.2SO.sub.4.fwdarw.(NH.sub.4).sub.2SO.sub.4
(5)
[0213] A commercial objective for the present invention is the
production of additional HCN over what is normally prepared from AN
production reactors by using a hot AN reactor effluent stream feed
that is fed CH.sub.3OH by injection to a second "on purpose HCN
production" reactor. This protocol prevents the waste of NH.sub.3,
heat and O.sub.2 components already contained in the hot reactive
gas stream from the AN production reactor. This objective is
accomplished without degrading the AN, ACN, and HCN products that
are already present in the exit gas from the primary reactor. A
significant benefit is realized from combining the product flows
from two serially positioned reactors because it enables all the
combined products from both reactors to be isolated together
without additional separation and purification operations. This
process also has the benefit of significantly reducing the amount
of acid needed for neutralizing the excess or unconverted NH.sub.3
or other alternative means for eliminating NH.sub.3 from the
effluent streams. The reduction in the formation of large amounts
of highly contaminated ammonium sulfate waste product is also a
significant added benefit of the present invention.
[0214] The catalyst compositions of the present invention enable
the use of low NH.sub.3 and O.sub.2 gas levels, particularly those
that exist in outlet streams from AN production reactors at high
(e.g., 400 to 500.degree. C.) temperatures, and in the presence of
many contaminants and products produced in the effluent stream from
the AN production reactors. In the conventional art, such gas
stream contaminants and by-products are considered spent and are
treated as waste. In various exemplary embodiments using simulated
feed conditions, the unconverted NH.sub.3 is converted to HCN
and/or ACN by reaction with CH.sub.3OH, EtOH or other alcohols. The
new effluent stream from two serially positioned reactors (an
existing AN reactor and an ammoxidation reactor outside of the AN
reactor) contains an increased overall amount of HCN and/or ACN
produced as a result of the catalytic process without additional
separation and purification operations. The removal of the
unconverted NH.sub.3 also beneficially results in a significantly
reduced amount of ammonium sulfate waste and sulfuric acid needed
for neutralization. Thus, the catalysts of the present invention
allow for a process that is environmentally and economically
superior to conventional processes.
[0215] Due to the limitations inherent in conventional AN
production catalysts and process performance, AN reactor effluent
streams typically contain unconverted NH.sub.3 and O.sub.2. This
residual NH.sub.3 requires additional processing (i.e.,
separation/neutralization) to avoid rapid and unwanted
polymerization and the formation of undesired side reactions and/or
fouling solids in downstream equipment and/or measures to mitigate
potentially detrimental environmental emissions. The removal of
unconverted NH.sub.3 also leads to a significant reduction in the
sulfuric acid demand for neutralization of the ammonia as well as
the ammonium sulfate waste that is generated as a result of the
neutralization. The present invention now makes it possible to
opportunistically convert this currently unused, wasted and
potentially detrimental NH.sub.3 (and O.sub.2) into useful HCN
products by reacting the "as is" feed gas product effluent
originating from an AN production plant with alcohols such as
CH.sub.3OH using the novel catalyst compositions of the present
invention as described herein, thereby boosting the overall yield
of HCN.
[0216] Although AN and HCN production catalysts have existed
commercially for years, the catalysts are generally unpredictable
and complex, typically consisting of a mixture of micro-crystalline
and nano-sized solids containing such disparate elements such as
Sb, Bi, Fe, and Mo and requiring support adhesion chemistry to
attach the catalyst to inert surface materials to ensure their
proper functioning. In contrast, the catalysts of the present
invention achieved high yields with short residence times of 0.001
to 50 seconds, and with selectivities of >90%, such as >95%,
such as >97%, such as >99%, even under severe thermal and
shear conditions. These observed performances are also possible
under conventional engineering controls.
[0217] In an exemplary embodiment, an advanced packed bed reactor
was utilized for on-purpose HCN production using a simulated feed
as an AN reactor effluent to meet the dual constraints of pressure
drop and heat transfer limits that are present in existing AN
production plants.
[0218] In an exemplary embodiment, a structured packed bed using a
monolith coated with the catalyst composition of the present
invention to generate on-purpose HCN via CH.sub.3OH ammoxidation
while incurring a low pressure drop and minimal or no degradation
of AN is one of the main features of the present invention. One
advantage of this structured packed bed technology is the facile
retrofitting of existing AN production plants based on conventional
technologies to accommodate the benefits associated with the
present invention, thereby significantly reducing the majority of
the capital and operating costs otherwise required for a new
standalone plant for commercial scale HCN production. In addition
to honeycomb monolith, other structured materials and/or substrates
can be used, such as, but not limited to, a catalytic foam
comprising or consisting of metal, cordierite, ceramic, metallic,
zeolite, carbides, mullite, alumina, clays, carbon or other
materials.
[0219] The present invention reflects the result of the inventors'
efforts to prepare "on-purpose" HCN at lower capital costs by
making use of the available residual NH.sub.3 generated in AN
reactor effluent streams. This process is sufficiently versatile to
be easily and rapidly integrated into other existing processes that
generate waste and/or residual NH.sub.3 and/or O.sub.2 in effluent
streams.
[0220] Ammonium sulfate represents a large volume waste product
formed when sulfuric acid is used to scrub the NH.sub.3 generated
from an AN reactor effluent stream. Use of the sulfuric acid
simultaneously acidifies the AN product to prevent its potentially
catastrophic polymerization into process-fouling poly-AN (PAN)
solids. The AN condensate is also observed to contain the
co-product HCN and several organic by-products, subsequently sent
to waste. The dilute and complex content of the AN production
reactor hot effluent stream is associated with the conditions
required to produce HCN through reaction with CH.sub.3OH.
[0221] While the source concentration is low, the NH.sub.3 content
represents a significant commercial quantity of HCN if the reaction
time and back pressure of any contacting device used could be
significantly reduced, and rendered effective at the low NH.sub.3
and O.sub.2 partial pressures/levels present in a typical AN
reactor effluent stream. The requirement that the AN and HCN
components of the stream not be degraded by the catalyst and
reaction zone treatment is critical to the success of the present
invention.
[0222] In addressing the failure of the conventional art to avoid
the generation of sulfate wastes, the present invention
significantly reduces the required quantity of ammonium sulfate
waste by using the residual NH.sub.3 instead as raw material for
the production of a HCN co-product prior to acid neutralization of
the AN production process.
[0223] The conventional art describes a Zn.sup.2+ ion-based
reversible NH.sub.3 recovery technology in U.S. Pat. No. 6,838,069
which is incorporated by reference in its entirety. The technology
of the present invention represents a means for pre-concentrating
the NH.sub.3 present in the effluent stream to render it more
concentrated.
[0224] The present invention increases the yield of one or both of
the main co-products (i.e., HCN and ACN) after the preparation of
AN in an AN reactor while (1) saving on the raw material costs
associated with the increase in co-product yields; and (2)
achieving the same or superior conversion and selectivity to the
desired co-products (on a carbon basis) as obtained with the use of
alcohols such as CH.sub.3OH, EtOH, and the like. In multiple
embodiments, CH.sub.3OH ammoxidation chiefly yielded HCN while EtOH
ammoxidation yielded both HCN and ACN in a simulated effluent feed
containing AN. The relative amounts of HCN and ACN can be
controlled by employing an alcohol mixture with varying ratios of
CH.sub.3OH to EtOH. A desirable increase in the production of HCN
and ACN during the production of AN can be achieved using crude
alcohol mixtures.
[0225] A significant distinction between the present invention and
the conventional art is the novel high performance catalyst
compositions as described herein and a means for decoupling the
primary reactor catalyst/process and its limitations from NH.sub.3
conversion by using a separate series reactor in the effluent line.
This arrangement enables the primary reactor to continue to employ
conditions (e.g., O.sub.2/hydrocarbon ratio, NH.sub.3/NH.sub.3
ratio, temperature, superficial velocity, etc.) that are catalyst
optimized separately from the series reactor of this invention. As
used herein, "hydrocarbon" refers to organic compounds naturally
present in the effluent or added to the effluent that are generally
capable of reacting in an ammoxidation reaction with the catalyst
compositions of the present invention.
[0226] Another advantage of the present invention over the
conventional art is the preparation of HCN in combination (i.e.,
with reactors linked serially) with main AN and HCN flow streams so
as to eliminate the need to perform separate isolation and
purification steps of this second source of HCN. In contrast, the
conventional art performs AN production reactor modifications and
does not employ a second reactor such as the one present in an
embodiment of the invention. Also, in contrast to producing HCN by
a standalone process (the Andrussow process or direct CH.sub.3OH to
HCN reactor), the present invention significantly minimizes the
additional capital required for dedicated backend end separation
units (distillation columns, etc.) as it takes advantage of the
existing AN backend separation units.
[0227] There are still further major differences between the
present invention and the conventional art. Notably, the on-purpose
HCN production of the present invention is performed outside of the
primary AN reactor, but still preferably utilizes the highly
reactive and hot effluent stream from a AN reactor as a feed to a
separate "on purpose" HCN synthesis reactor. This unexpected
capability achieved by the present invention is made possible by
the highly active catalyst compositions of the present invention
that also result in a highly selective CH.sub.3OH ammoxidation when
contacted with the AN reactor effluent stream. It was also
discovered that in an exemplary embodiment of the present invention
a commercially significant high throughput rate can be achieved at
substantially low total pressures by the novel use of structured
catalytic packed beds, catalyst-coated tube(s) walls design or
other high gas-to-solid surface area reactor designs, to
accommodate high velocities, to enable high heat removal rates, and
to achieve the required low pressure drop. The reactor design also
has the benefit/advantage of being significantly compact compared
to the packed bed designs and fluidized bed designs of the prior
art.
[0228] The catalyst compositions of the present invention are
useful in processes for the ammoxidation of the combined feed of
CH.sub.3OH, or other primary alcohols, or blends of alcohols, with
an olefin or blends of olefins selected from propylene, isobutylene
or mixtures thereof, to thereby form HCN, AN, methacrylonitrile and
mixtures thereof, respectively.
[0229] In this invention, the on-purpose HCN production is applied
to and occurs outside of the primary AN production reactor using
the hot, chemically unstable (with respect to polymerization) crude
AN gas stream containing residual excess raw materials (e.g.,
propylene, NH.sub.3 and O.sub.2), and by-products (e.g., H.sub.2O,
CO, and CO.sub.2), and other co-products (e.g., CH.sub.3CN and the
like), and a first HCN portion. This hot gas mixture exits fully
from a first AN reactor and represents the feed gas to the
(secondary) reactor of the present invention where a low molecular
weight aliphatic alcohol, such as CH.sub.3OH, is injected into the
stream, typically immediately upstream of the catalyst composition
of the present invention. In an exemplary embodiment, the simulated
feed is preheated before entering the ammoxidation reactor.
[0230] The production of a second portion of HCN product, formed
within the above-described gas stream is accomplished by the
present invention through the combined use of a newly formulated,
highly active, and uniquely selective, CH.sub.3OH ammoxidation
catalyst, combined with a novel use of a structured bed reactor.
This design provides a compact configuration utilizing high
velocities at a low pressure drop enabling non-degradative, high
speed and efficient mass contact to promote the selective HCN
formation reaction. Despite the large gas flow rate involved, the
reactor is compact compared to the regular packed and fluidized
conventional bed designs.
[0231] In an exemplary embodiment, the on-purpose HCN production is
performed outside of the primary AN synthesis reactor through the
use of a secondary fluidized bed or fixed bed reactor containing a
highly active and selective CH.sub.3OH ammoxidation catalyst and
preferably using a structured fixed bed reactor (catalyst bed(s)
could be placed inside the heat transfer tubes, outside or coated
on the heat exchanger tube surface) to achieve required heat
removal and minimize pressure drop. The preferred reactor will also
be compact compared to the fluid bed designs of the prior art. This
in-line processing provides a novel, adequate and desirable
solution for converting unconverted NH.sub.3 into value-added
HCN.
[0232] In various exemplary embodiments, NH.sub.3 is selectively
oxidized to N.sub.2 in the lack of CH.sub.3OH in the feed
regardless of the presence or absence of AN in the simulated feed.
The present invention may simply be used to oxidize and eliminate
the excess NH.sub.3 by reaction with excess O.sub.2 already present
in the AN reactor effluent stream. In this embodiment, no
additional HCN or ACN is produced, but this approach leads to a
significant reduction or complete elimination of the NH.sub.3
neutralization required in the downstream quench in the AN
production process. The present invention may also simply be
incorporated or integrated into any NH.sub.3 removal process to
avoid conventional extraction, stripping or absorption means. In
various exemplary embodiments, the catalyst compositions of the
present invention allow for the selective catalytic oxidation (SCO)
of NH.sub.3, such as from the reactor effluent of a chemical
process or a NH.sub.3 removal system such as from mobile exhaust
sources and/or stationary exhaust sources, to N.sub.2 in the
presence of O.sub.2. The source of the O.sub.2 may be from the air
or independently provided via a feed line or already present with
NH.sub.3.
EXAMPLES
[0233] Catalyst Composition Preparation
[0234] In an exemplary embodiment, the source compounds of, for
example, the elements Fe, Bi, Cr, Co, Sb, Gd, Mg, and Ru from
compositional DOE are mixed in an aqueous solution to form mixture
A. The source compounds of, for example, Mo and Si are mixed in an
aqueous solution to form mixture B. The mixture A and the mixture B
are combined, in the presence of ammonia, to form a precipitate
slurry mixture. After filtration, the resultant precipitate is
dried and calcined to form the catalyst composition. The formed
catalyst composition can be further applied onto various
conventional carriers via conventional means. Several preparation
examples are provided for illustration purposes only.
[0235] Testing Conditions
[0236] In a particular embodiment, the CH.sub.3OH ammoxidation
reactions are conducted in a 3/8'' stainless steel fixed bed tubing
reactor at atmospheric pressure. The catalyst is mixed with 0.5 g
inert .alpha.-Al.sub.2O.sub.3.
The CH.sub.3OH conversion (X.sub.CH3OH) is calculated using the
following formula:
X.sub.CH3OH=(1-[CH3OH].sub.OUT/([CH3OH].sub.OUT+[CO].sub.OUT+[CO2].sub.O-
UT+[HCN].sub.OUT))*100%
wherein [CH.sub.3OH].sub.OUT, [CO].sub.OUT, [CO.sub.2].sub.OUT and
[HCN].sub.OUT are concentrations (vol. %) in the reactor effluent.
HCN selectivity (S.sub.HCN) is calculated using the following
formula:
S.sub.HCN=([HCN].sub.OUT/([CO].sub.OUT+[CO2].sub.OUT+[HCN].sub.OUT)*100%
HCN yield (Y.sub.HCN) is calculated using the following
formula:
Y.sub.HCN=X.sub.CH3OH*S.sub.HCN
W/F (gs)/(STP ml) is the contact time where W is weight of a
catalyst; F is total inlet feed of gases in (STP ml)/s. For
CH.sub.3OH ammoxidation, the catalyst is typically tested at
370.degree. C., W/F=0.2 (gs)/ml, and a feed composition of NH.sub.3
(7 vol. %), CH.sub.3OH (6.9 vol. %), O.sub.2 (13 vol. %) balanced
with helium at W/F=0.20 (gs)/ml for E1-E9, W/F=0.51 (gs)/ml for
CE1*and CE2*, W/F=0.025 (gs)/ml for E10 and E11, 370.degree. C. for
E1-E6 and CE1-CE5, and 400.degree. C. for E7-E1. E12 in Example 20
was tested with a feed composition of NH.sub.3 (2.8 vol. %),
CH.sub.3OH (1.49 vol. %), O.sub.2 (4.97 vol. %), AN (2.18 vol. %)
and balanced with helium at W/F=0.0083 (gs)/ml and 400.degree.
C.
[0237] Catalyst Coated on a Monolith
[0238] Approximately 230 cells per square inch (cpsi) of cordierite
monoliths are dip-coated with catalyst powder slurry. In a typical
slurry preparation, approximately 1.2 kg of catalyst are added with
20 kg CeZr grinding media balls and 4.8 kg deionized water and
ball-milled for 24 hours to get a slurry having a solids content
about 20% by weight. If needed, various additives such as water and
binders such as silica sol (e.g., Nalco 2327, 40% silica) can be
added. The resultant slurry which had an average particle size of
0.3 microns and a pH of 1.5, was used to dip coat desired monolith
coupons. Compressed air up to about 20 psi was used to blow out
excess slurry from the channels. The coated monoliths were dried at
130-150.degree. C. for up to 3 hours. The above dip-coating and
drying steps were repeated several times to obtain a target
catalyst loading of about 0.1-0.3 g/cc of monolith volume. The
monoliths thus coated were calcined in air at 550.degree. C. for 3
hours, with temperature ramp up and ramp down rates of 10.degree.
C./min. The slurry solids content, particle size, pH, viscosity,
and other parameters were adjusted or optimized as needed to
achieve commercially durable adhesion and uniform coating.
Comparative Example 1 (CE1,
Mn.sub.1.25P.sub.1Zn.sub.0.01O.sub.x)
[0239] A Mn.sub.1.25P.sub.1Zn.sub.0.01O.sub.x catalyst was prepared
by a precipitation method according to U.S. Pat. No. 7,763,225
which discloses a CH.sub.3OH ammoxidation catalyst and process for
HCN production. The catalyst was tested at 370.degree. C. and
W/F=0.51 (gs)/ml. The feed composition was NH.sub.3 (7 vol. %),
CH.sub.3OH (6.9 vol. %), O.sub.2 (13 vol. %) and balanced with
helium. The results showed 12.4% CH.sub.3OH conversion and 11.6%
HCN yield. The testing results are also shown in Table 1 and FIG.
3.
TABLE-US-00001 TABLE 1 Comparison of the catalysts of the present
invention with comparative catalysts W/F X Y Example Catalyst (g
s)/ml CH.sub.3OH, % HCN, % CE1 Mn.sub.1.25P.sub.1Zn.sub.0.01O.sub.x
0.51 12.4 11.6 CE2 Fe--Sb--U based mixed oxide 0.20 32.1 31.4 0.51
36.1 33.9 E1
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Sb.sub.0.26Gd.sub.2.0Ru.sub.1.0Co.s-
ub.2.89Mg.sub.1.17O.sub.x 0.20 91.7 79.5 E2
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Sb.sub.0.26Ce.sub.0.22Gd.sub.2.0Re.-
sub.0.26Ru.sub.1.0Ni.sub.2.89Sn.sub.0.22O.sub.x 0.20 89.3 76.4 E3
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Ce.sub.0.22Re.sub.0.26Ru.sub.1.0Mn.-
sub.0.26O.sub.x 0.20 87.0 73.2 E4
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Ce.sub.0.22Co.sub.2.89Mg.sub.1.17Mn-
.sub.0.26O.sub.x 0.20 83.5 75.0 E5
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Sb.sub.0.26Re.sub.0.26Ru.sub.1.0Ni.-
sub.2.89Zn.sub.2.89Mg.sub.1.17O.sub.x 0.20 77.1 67.4 E6
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Sb.sub.0.26Gd.sub.2.0Ni.sub.2.89Mn.-
sub.0.26Zn.sub.2.89Sn.sub.0.22O.sub.x 0.20 81.7 70.8 CE3
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Gd.sub.2.0Re.sub.0.26Ni.sub.2.89Mn-
.sub.0.26Cu.sub.2.89Mg.sub.1.17O.sub.x 0.20 51.4 7.1 CE4
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Gd.sub.2.0Re.sub.0.26Ni.sub.2.89Co-
.sub.2.89Zn.sub.2.89O.sub.x 0.20 27.9 23.8 CE5
FeMo.sub.47.97Bi.sub.0.13Cr.sub.0.07Cu.sub.2.89Zn.sub.2.89Co.sub.2.89M-
n.sub.0.26Mg.sub.1.17O.sub.x 0.20 50.8 31.8 Note: X CH.sub.3OH, % =
CH.sub.3OH conversion; Y HCN, % = HCN yield. E1-E6 represent
catalysts of the present invention; CE1-CE5 represent comparative
catalysts; CE1 is a comparative catalyst of CH.sub.3OH oxidation to
produce HCN. All testing was conducted at 370.degree. C. and W/F =
0.20 (g s)/ml except for CE1 at 0.51(g s)/ml and CE2 at W/F = 0.20
and 0.51 (g s)/ml.
Comparative Example 2 (CE2, a Fe--Sb--U Based Mixed Oxide)
[0240] A Fe--Sb--U based mixed oxide catalyst was prepared by a
precipitation method according to U.S. Pat. No. 7,763,225 which
discloses a propylene ammoxidation catalyst. The catalyst was
tested at 370.degree. C., a feed composition of NH.sub.3 (7 vol.
%), CH.sub.3OH (6.9 vol. %), O.sub.2 (13 vol. %) and balanced with
helium, and W/F=0.2 and 0.51 (gs)/ml conditions, respectively. This
catalyst showed lower HCN yield at W/F 0.20 (gs)/ml than that at
W/F=0.51 (gs)/ml. Increasing W/F from 0.20 to 0.51 slightly
increased the CH.sub.3OH conversion and HCN yield. The results are
also listed in Table 1 and FIG. 3 for comparison.
Example 1 (E1,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Co.sub.2.89Sb.sub.0.26Gd.sub.2.0Mg.su-
b.1.17Ru.sub.1.0Si.sub.33.48O.sub.x)
[0241] Mixture A was prepared by stirring 1250 ml of deionized
water and then adding with 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O,
0.56 g of Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Co(NO.sub.3).sub.2.6H.sub.2O, 17 g of
Gd(NO.sub.3).sub.3.6H.sub.2O.sub., 5.64 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 1.1 g of SbCl.sub.3, 3.84 g of
RuCl.sub.3, and a mixture of 1.16 g of Bi(NO.sub.3).sub.3.5H.sub.2O
and 20 ml of 50/50 mixture by volume of HNO.sub.3 (70%) and
deionized water. Mixture B was prepared by stirring 500 ml of
deionized water and then adding with 159.334 g of ammonium
heptamolybdate (AHM) and 94.6 g of silica sol (40 wt % silica).
Mixture A and a 50/50 mixture of ammonia (28-30%) and deionized
water were added to mixture B with a pH of 7.8-8.2 to form
precipitate slurry of the catalyst precursor. The precipitate
slurry was filtered and then dried at 120.degree. C. overnight to
get dry powder. The dry powder was transferred into an oven
preheated at 300.degree. C. for 1 hour and calcined at 550.degree.
C. for 3 hours with a heating rate of 10.degree. C./min from
300.degree. C. to 550.degree. C. The resultant calcined powder was
then directly used as catalyst for testing. The catalyst was tested
at 370.degree. C., W/F=0.2 (gs)/ml, and a feed composition of
NH.sub.3 7 (vol. %), CH.sub.3OH (6.9 vol. %), O.sub.2 (13 vol. %)
and balanced with helium. The results showed 91.7% CH.sub.3OH
conversion and 86.7% HCN selectivity. HCN yield was 79.5%.
Example 2 (E2,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Ni.sub.2.89Sn.sub.0.22Sb.sub.0.26Gd.s-
ub.2.0Re.sub.0.26Ce.sub.0.22Ru.sub.1.0Si.sub.34.88O.sub.x)
[0242] Mixture A was prepared similarly to Example 1 using 1250 ml
of deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g
of Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Ni(NO.sub.3).sub.3.6H.sub.2O, 17 g of
Gd(NO.sub.3).sub.3.6H.sub.2O.sub., 1.8 g of
Ce(NO.sub.3).sub.3.6H.sub.2O, 1.45 g of SnCl.sub.4.5H.sub.2O, 1.12
g of SbCl.sub.3, 3.84 g of RuCl.sub.3, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared
similarly to Example 1 using 159.334 g of ammonium heptamolybdate
(AHM), 2.12 g of NH.sub.4ReO.sub.4, and 98.6 g of silica sol (40 wt
% silica). The subsequent steps of mixing, precipitation,
filtering, drying and calcination are the same as Example 1. The
catalyst was tested under the same conditions as in Example 1. The
results showed 89.3% CH.sub.3OH conversion and 85.6% HCN
selectivity. HCN yield was 76.4%.
Example 3 (E3,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Mn.sub.0.26Re.sub.0.26Ce.sub.0.22Ru.s-
ub.1.0Si.sub.24.36O.sub.x)
[0243] Mixture A was prepared similarly to Example 1 using 1250 ml
of deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g
of Cr(NO.sub.3).sub.3.9H.sub.2O, 1.8 g of
Ce(NO.sub.3).sub.3.6H.sub.2O, 1.23 g of
Mn(NO.sub.3).sub.2.4H.sub.2O.sub., 2.12 g of NH.sub.4ReO.sub.4,
3.84 g of RuCl.sub.3, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared
similarly to Example 1 using 159.33 g of ammonium heptamolybdate
(AHM) and 68.84 g of silica sol (40 wt % silica). The subsequent
steps of mixing, precipitation, filtering, drying and calcination
were the same as in Example 1. The catalyst was tested under the
same conditions as in Example 1. The results showed 87.0%
CH.sub.3OH conversion and 84.1% HCN selectivity. HCN yield was
73.2%.
Example 4 (E4,
Mo.sub.47.79FeBi.sub.0.13Cr.sub.0.07Ce.sub.0.22Co.sub.2.89Mg.sub.1.17Mn.s-
ub.0.26O.sub.x)
[0244] Mixture A was prepared similarly to Example 1 using 1250 ml
of deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g
of Cr(NO.sub.3).sub.3.9H.sub.2O, 1.77 g of
Ce(NO.sub.3).sub.3.6H.sub.2O, 15.46 g of
Co(NO.sub.3).sub.2.6H.sub.2O, 5.49 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 1.21 g of
Mn(NO.sub.3).sub.2.4H.sub.2O, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared
similarly to Example 1 using 159.39 g of ammonium heptamolybdate
(AHM) and 62.5 g of silica sol (40 wt % silica). The subsequent
steps of mixing, precipitation, filtering, drying and calcination
were the same as in Example 1. The catalyst was tested under the
same conditions as in Example 1. The results showed 83.5%
CH.sub.3OH conversion and 89.8% HCN selectivity. HCN yield was
75.0%.
Example 5 (E5,
Mo.sub.47.79FeBi.sub.0.13Cr.sub.0.07Ni.sub.2.89Zn.sub.2.89Sb.sub.0.26Mg.s-
ub.1.17Re.sub.0.26Ru.sub.1.0Si.sub.32.42O.sub.x)
[0245] Mixture A was prepared similarly to Example 1 using 1250 ml
of deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g
of Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Ni(NO.sub.3).sub.3.6H.sub.2O, 16.17 g of
Zn(NO.sub.3).sub.2.6H.sub.2O, 5.64 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 2.12 g of NH.sub.4ReO.sub.4, 3.84 g
of RuCl.sub.3, 1.11 g of SbCl.sub.3, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared by
stirring 500 ml of deionized water and then adding with 159.33 g of
ammonium heptamolybdate (AHM) and 91.6 g of silica sol (40 wt %
silica). The subsequent steps of mixing, precipitation, filtering,
drying and calcination were the same as in Example 1. The catalyst
was tested under the same conditions as in Example 1. The results
showed 77.1% CH.sub.3OH conversion and 87.3% HCN selectivity. HCN
yield was 67.4%.
Example 6 (E6,
Mo.sub.47.79FeBi.sub.0.13Cr.sub.0.07Ni.sub.2.89Zn.sub.2.89Mn.sub.0.26Sn.s-
ub.0.22Sb.sub.0.26Gd.sub.2.0Si.sub.31.36O.sub.x)
[0246] Mixture A was prepared similarly to Example 1 using 1250 ml
of deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g
of Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Ni(NO.sub.3).sub.3.6H.sub.2O, 1.22 g of
Mn(NO.sub.3).sub.2.4H.sub.2O, 17 g of Gd(NO.sub.3).sub.3.6H.sub.2O,
1.45 g of SnCl.sub.4.5H.sub.2O, 1.12 g of SbCl.sub.3, and a mixture
of 1.16 g of Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50
mixture of HNO.sub.3 (70%) and deionized water. Mixture B was
prepared by stirring 500 ml of deionized water and then adding with
159.33 g of ammonium heptamolybdate (AHM) and 88.6 g of silica sol
(40 wt % silica). The subsequent steps of mixing, precipitation,
filtering, drying and calcination were the same as Example 1. The
catalyst was tested under the same conditions as in Example 1. The
results showed 81.7% CH.sub.3OH conversion and 86.7% HCN
selectivity. HCN yield was 70.8%.
Comparative Example 3 (CE3,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Ni.sub.2.89Cu.sub.2.89Mn.sub.0.26Gd.s-
ub.2.0Mg.sub.1.17Re.sub.0.26Si.sub.35.75O.sub.x)
[0247] Mixture A was prepared similarly to Example 1 using 1250 ml
deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g of
Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Ni(NO.sub.3).sub.3.6H.sub.2O, 12.64 g of
Cu(NO.sub.3).sub.2.6H.sub.2O, 1.23 g of
Mn(NO.sub.3).sub.2.4H.sub.2O, 5.64 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 17 g of Gd(NO.sub.3).sub.3.6H.sub.2O,
and a mixture of 1.16 g of Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml
of 50/50 mixture of HNO.sub.3 (70%) and deionized water. Mixture B
was prepared similarly to Example 4 using 159.33 g of ammonium
heptamolybdate (AHM), 2.12 g of NH.sub.4ReO.sub.4, and 101 g of
silica sol (40 wt % silica). The subsequent steps of mixing,
precipitation, drying and calcination were the same. The catalyst
was tested under the same conditions as in Example 1. The results
showed 51.4% CH.sub.3OH conversion and 13.9% HCN selectivity. HCN
yield was 7.1%.
Comparative Example 4 (CE4,
Mo.sub.47.79FeBi.sub.0.13Cr.sub.0.07Ni.sub.2.89Zn.sub.2.89Co.sub.2.89Gd.s-
ub.2.0Re.sub.0.26Si.sub.38.44O.sub.x)
[0248] Mixture A was prepared similarly to Example 1 using 1250 ml
deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g of
Cr(NO.sub.3).sub.3.9H.sub.2O, 15.8 g of
Ni(NO.sub.3).sub.3.6H.sub.2O, 16.2 g of
Zn(NO.sub.3).sub.2.6H.sub.2O.sub., 15.8 g of
Co(NO.sub.3).sub.2.6H.sub.2O, 17 g of Gd(NO.sub.3).sub.3.6H.sub.2O,
and a mixture of 1.16 g of Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml
of 50/50 mixture of HNO.sub.3 (70%) and deionized water. Mixture B
was prepared similarly to Example 4 using 159.33 g of ammonium
heptamolybdate (AHM), 2.12 g of NH.sub.4ReO.sub.4, and 108.6 g of
silica sol (40 wt % silica). The subsequent steps of mixing,
precipitation, drying and calcination were the same. The catalyst
was tested under the same conditions as in Example 1. The results
showed 27.9% CH.sub.3OH conversion and 85.3% HCN selectivity. HCN
yield was 23.8%.
Comparative Example 5 (CE5, Mo.sub.47.79Fe
Bi.sub.0.13Cr.sub.0.07Cu.sub.2.89Zn.sub.2.89Co.sub.2.89Mn.sub.0.26Mg.sub.-
1.17Si.sub.32.67O.sub.x)
[0249] Mixture A was prepared similarly to Example 1 using 1250 ml
deionized water, 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g of
Cr(NO.sub.3).sub.3.9H.sub.2O, 12.64 g of
Cu(NO.sub.3).sub.2.6H.sub.2O, 1.22 g of
Mn(NO.sub.3).sub.2.4H.sub.2O, 16.17 g of
Zn(NO.sub.3).sub.2.6H.sub.2O, 5.644 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 15.82 g of
Co(NO.sub.3).sub.2.6H.sub.2O, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared
similarly to Example 1 using 159.33 g of ammonium heptamolybdate
(AHM) and 92.3 g of silica sol (40 wt % silica). The subsequent
steps of mixing, precipitation, drying and calcination were the
same. The catalyst was tested under the same conditions as in
Example 1. The results showed 50.8% CH.sub.3OH conversion and 62.5%
HCN selectivity. HCN yield was 31.8%.
Example 7 (E7,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Ce.sub.0.22Co.sub.2.89Mg.sub.1.17Mn.s-
ub.0.26Ti.sub.14.64O.sub.x)
[0250] Mixture A was prepared by stirring 1250 ml of deionized
water and then adding with 7.6 g of Fe(NO.sub.3).sub.3.9H.sub.2O,
0.56 g of Cr(NO.sub.3).sub.3.9H.sub.2O, 1.77 g of
Ce(NO.sub.3).sub.3.6H.sub.2O, 15.46 g of
Co(NO.sub.3).sub.2.6H.sub.2O, 5.49 g of
Mg(NO.sub.3).sub.3.6H.sub.2O, 1.21 g of
Mn(NO.sub.3).sub.2.4H.sub.2O, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 20 ml of 50/50 mixture by volume
of HNO.sub.3 (70%) and deionized water. Mixture B was prepared by
stirring 500 ml of deionized water and then adding with 159.39 g of
ammonium heptamolybdate (AHM) and 25 g of titanium dioxide powder
(TiO.sub.2, approx. 88%). Mixture A and a 50/50 mixture of NH.sub.3
(28-30%) and deionized water were added to mixture B with a pH of
7.8-8.2 to form precipitate slurry of the catalyst precursor.
[0251] The precipitate slurry was filtered with washing assistance
of using 1000 ml deionized water. The subsequent steps of drying
and calcination were the same as Example 1. The catalyst was tested
at 400.degree. C. and other conditions are the same as those in
Example 1. The results showed 97.6% CH.sub.3OH conversion and 75.8%
HCN yield, and are also listed in Table 2.
Example 8 (E8,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Ce.sub.0.22Co.sub.2.89Mg.sub.1.17Mn.s-
ub.0.26Si.sub.22.12O.sub.x)
[0252] Example 8 was prepared similarly to Example 7 but 25 g of
SiO.sub.2 powder (high surface area, BET SA=730 m.sup.2/g) was used
to substitute TiO.sub.2 powder in preparing Mixture B. All other
preparation conditions were the same as those in Example 7. The
catalyst was tested at the same conditions as those in Example 7.
The results showed 92.1% CH.sub.3OH conversion and 74.6% HCN yield,
and are also listed in Table 2.
TABLE-US-00002 TABLE 2 Testing results of various supports addition
on CH.sub.3OH ammoxidation Effluent product, % Example CO.sub.2
NH.sub.3 CH.sub.3OH O.sub.2 HCN CO X CH.sub.3OH, % Y HCN, % E7
(TiO.sub.2) 0.95 3.12 0.13 6.49 4.16 0.25 97.6 75.8 E8 (SiO.sub.2)
0.85 2.64 0.48 6.71 4.57 0.22 92.1 74.6 E9 0.26 2.99 1.60 8.04 4.31
0.04 74.2 69.4 Note: E9 has no support added.
Example 9 (E9,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Ce.sub.0.22Co.sub.2.89Mg.sub.1.17Mn.s-
ub.0.26O.sub.x)
[0253] Example 9 was prepared similarly to Example 7 but the
TiO.sub.2 powder was not added. Mixture B was prepared by stirring
500 ml of deionized water and then adding with 159.39 g of ammonium
heptamolybdate (AHM). Deionized water was not used in the
filtration and all other preparation conditions were the same as
those in Example 7. The catalyst was tested at the same conditions
as those in Example 7. The results showed 74.2% CH.sub.3OH
conversion and 69.4% HCN yield. Table 2 compared the results of
Examples 7, 8, and 9.
Example 10 (E10,
FeMo.sub.47.79Bi.sub.0.13Cr.sub.0.07Sn.sub.1.12Sb.sub.0.76Si.sub.24.91O.s-
ub.x)
[0254] Mixture A was prepared similarly to Example 1 using 7.6 g of
Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g of
Cr(NO.sub.3).sub.3.9H.sub.2O, 3.26 g of SbCl.sub.3, 7.4 g of
SnCl.sub.4.5H.sub.2O, and 1.16 g of Bi(NO.sub.3).sub.3.5H.sub.2O.
Mixture B was prepared similarly to Example 1 using 159.334 g of
ammonium heptamolybdate (AHM) and using 70.4 g of silica sol (40 wt
% silica). The subsequent steps of mixing, precipitation,
filtering, drying and calcination are the same as Example 1. The
catalyst was tested W/F=0.025 (gs)/ml and a feed composition of
NH.sub.3 (9.2 vol. %), CH.sub.3OH (8.0 vol. %), O.sub.2 (12 vol. %)
and balanced with helium at various temperatures. The results
showed 71.9% CH.sub.3OH conversion and 67.5% HCN yield at
400.degree. C. Additional results are shown in FIGS. 4A and 4B.
Example 11 (E11,
FeMo.sub.2.17Bi.sub.0.13Cr.sub.0.07Sb.sub.0.53Sn.sub.0.48Si.sub.22.65O.su-
b.x)
[0255] Mixture A was prepared similarly to Example 1 using 3000 ml
of deionized water and 76.0 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 5.60
g of Cr(NO.sub.3).sub.3.9H.sub.2O, 29.0 g of SnCl.sub.4.5H.sub.2O,
22.3 g of SbCl.sub.3, and a mixture of 11.6 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 100 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Ammonium heptamolybdate (AHM)
is not added to Mixture B. The Mixture B was prepared by stirring
4000 ml of deionized water and then adding with 640 g of silica sol
(40 wt % silica). After the mixing and precipitation, the
precipitate slurry was filtered to get a total of 1950.4 g of wet
precipitate. Approximately 79.52 g of the wet precipitate was added
with 2.766 g of molybdenum trioxide and mixed for 1 hour. The
subsequent steps of drying and calcination were the same as Example
10. The catalyst was tested under the same conditions as those in
Example 10. The results showed 76.4% CH.sub.3OH conversion and
65.7% HCN yield at 400.degree. C. Additional results are shown in
FIGS. 4A and 4B.
Example 12 (E12,
FeMo.sub.2.81Bi.sub.0.13Cr.sub.0.07Sb.sub.0.76Sn.sub.1.12Ce.sub.0.76Zr.su-
b.3.11Si.sub.14.95O.sub.x)
[0256] Mixture A was prepared using 200 ml of deionized water and
7.64 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.56 g of
Cr(NO.sub.3).sub.3.9H.sub.2O, 7.4 g of SnCl.sub.4.5H.sub.2O, 3.27 g
of SbCl.sub.3, and a mixture of 1.16 g of
Bi(NO.sub.3).sub.3.5H.sub.2O and 10 ml of 50/50 mixture of
HNO.sub.3 (70%) and deionized water. Mixture B was prepared using
400 ml of deionized water, 11.3 g of ceria doped zirconium
hydroxide (25.5% CeO.sub.2) and 42.25 g of silica sol (40 wt %
silica). After the mixing and precipitation, the precipitate slurry
was filtered to get a total of 102 g of wet precipitate.
Approximately 54.59 g of the wet precipitate was added with 4.71 g
of molybdic acid and mixed for 1 hour. The subsequent steps of
drying and calcination were the same as in Example 1. The catalyst
was tested at the conditions listed in Examples 19, 20, and 21.
Example 13 (Temperature Optimization Study of E1 Catalyst)
[0257] E1 catalyst was tested at 350.degree. C., 375.degree. C.,
400.degree. C., 425.degree. C., 450.degree. C., 475.degree. C. and
500.degree. C. and W/F=0.05 (gs)/ml with a feed composition
comprising NH.sub.3 (7 vol. %), CH.sub.3OH (6.9 vol. %), and
O.sub.2 (13 vol. %) balanced with helium. The test results are
shown in FIG. 5. The results showed that CH.sub.3OH conversion
increased with temperature and HCN selectivity unexpectedly
increased with temperature between 350.degree. C. and 400.degree.
C. and started to decrease with temperatures above 400.degree. C.
The maximum yield of HCN is unexpectedly achieved at 425.degree.
C.
Example 14 (CH.sub.3OH and NH.sub.3 Use Efficiencies of E1
Catalyst)
[0258] E1 catalyst was tested at a temperature from 350.degree. C.
to 450.degree. C. and W/F=0.097 (gs)/ml. The feed composition was
NH.sub.3 (7 vol. %), CH.sub.3OH (6.9 vol. %), O.sub.2 (13 vol. %)
and balanced with helium. The test results are shown in FIGS. 6A
and 6B. The results also show a linear correlation between
CH.sub.3OH and NH.sub.3 conversion. Their usages are beyond 95% at
temperature at and above 425.degree. C.
Example 15 (E15, Coating E10 Catalyst onto a Monolith)
[0259] A standard 230 cpsi monolith of 6''.times.6'' was core
drilled into 1.5''.times.6'' pieces. As described, approximately
1.32 kg of the E10 catalyst powder was added with 3.98 kg deionized
water and ball-milled for 24 hrs to make slurry having solids
content about 25% by weight. After each dip-coating, the excess
liquid was removed by an air knife at 20 psi. The coated monolith
was dried at 150.degree. C. for 1 hr and finally calcined at
550.degree. C. for 3 hrs to get sample. The above dip-coating and
drying steps were repeated twice to eventually obtain a target
catalyst loading of about 0.11 g/cc of monolith volume.
Example 16 (Simulated AN Reactor Effluent Test in Fixed-Bed
Monolith Reactor)
[0260] A monolith coated per the process described in Example 15
was tested in a simulated AN reactor effluent containing 1%
CH.sub.3OH, 1% NH.sub.3, 3% AN, 4% O.sub.2 and the remainder
N.sub.2. The feed to this catalytic monolith reactor was set at
351.degree. C. and 20 psig and a superficial space velocity of 4.1
s.sup.-1 was maintained. Under these conditions, a 99.8% CH.sub.3OH
conversion and 97.1% NH.sub.3 conversion was achieved along with,
88.6% HCN yield and negligible AN burning.
Example 17 (NH.sub.3 Destruction in the Absence of CH.sub.3OH in
Fixed-Bed Monolith Reactor)
[0261] The monolith and the test conditions in Example 16 were
repeated, except at 405.degree. C. inlet and without the CH.sub.3OH
in the feed. The feed composition for this test was 1% NH.sub.3, 4%
AN, 4% O.sub.2 and balanced with N.sub.2 at 377, 405, and
430.degree. C. and 19.4 psig. Under these conditions, NH.sub.3
conversions of 78% at 377.degree. C. and 100% at 405 and
430.degree. C. are achieved with negligible AN burning. Neither
significant nor detectable amount of NO.sub.x and N.sub.2O is
produced. Most of the NH.sub.3 was expected to be oxidized to
N.sub.2 and water. The results are listed in Table 3.
TABLE-US-00003 TABLE 3 Ammonia destruction in AN/O.sub.2 and in
O.sub.2 flow balanced with N.sub.2 Temper- ature NH.sub.3 AN Test
Feed (.degree. C.) conversion burning Example 1% NH.sub.3, 4% AN,
4% O.sub.2 377 78% negligible 17 Example 1% NH.sub.3, 4% AN, 4%
O.sub.2 405 100% negligible 17 Example 1% NH.sub.3, 4% AN, 4%
O.sub.2 430 100% negligible 17 Example 1% NH.sub.3, 4% O.sub.2 398
100% Not 18 applicable
Example 18 (NH.sub.3 Destruction in O.sub.2 in Fixed-Bed Monolith
Reactor)
[0262] The monolith and the test conditions in Example 17 were
repeated, except at a 398.degree. C. inlet and without the AN in
the feed. The feed composition for this test was 1% NH.sub.3, 4%
O.sub.2 and balanced with N.sub.2 at 398.degree. C. and 19.6 psig.
Under these conditions, a 100% NH.sub.3 conversion was achieved.
Neither significant nor detectable amounts of NO.sub.x and N.sub.2O
were produced. Most of the NH.sub.3 was expected to be oxidized to
N.sub.2 and water. The results are listed in Table 3.
Example 19 (Simulated AN Reactor Effluent Test in Packed Fixed-Bed
Reactor)
[0263] E10 catalyst was tested at 450.degree. C. and W/F=0.025
(gs)/ml. The tests were done with and without the presence of AN in
the feed. The E10 was a calcined powder sample and not coated
and/or applied on any other supports or carriers. The reactor feed
and effluent compositions are listed in Table 4. There was only a
slight change of CO and CO.sub.2 concentrations in the effluent
when AN was added to the reactor feed, indicating that AN was
practically not oxidized in the process according to the current
invention.
TABLE-US-00004 TABLE 4 Testing results of simulated AN reactor
effluent in packed fixed-bed reactor Feed and/or effluent product,
% CH.sub.3OH HCN HCN CO.sub.2 NH.sub.3 CH.sub.3OH O.sub.2 HCN CO AN
Conversion Selectivity Yield Feed 7.0 6.9 17.9 -- -- -- Effluent
0.18 1.37 0.03 8.41 6.37 0.10 0.00 99.58% 95.80% 95.40% Feed 7.0
6.9 17.9 0.79 -- -- -- Effluent 0.20 2.09 0.02 10.48 5.14 0.05 0.79
99.56% 95.24% 94.82%
Example 20 (Unexpected High Activity and Selectivity on E12)
[0264] E12 catalyst was tested at a temperature from 325.degree. C.
to 450.degree. C., W/F=0.0083 (gs)/ml, and a feed composition of
NH.sub.3 (2.8 vol. %), CH.sub.3OH (1.49 vol. %), O.sub.2 (4.97 vol.
%), AN (2.18 vol. %) balanced with helium. The results are shown in
FIG. 7. The CH.sub.3OH conversion and HCN yield increase with
increasing reaction temperature. About 90% HCN selectivity and
yield were achieved at 400.degree. C. and >97% at 450.degree.
C.
Example 21 (HCN Production from Propionitrile (PN) Ammoxidation on
E12)
[0265] E12 catalyst was tested at temperatures ranging from 350 to
475.degree. C., W/F=0.2 (gs)/ml, and a feed composition of O.sub.2
(10.1 vol. %), NH.sub.3 (6.10 vol. %), propionitrile (PN) (4.1 vol.
%) balanced with helium. PN conversion is calculated using the
following formula
X.sub.PN=(1-[PN].sub.OUT/[PN].sub.IN)*100%
where [PN].sub.IN is the concentration of PN in the feed in vol. %,
and [PN].sub.OUT is the concentration of PN in the effluent in vol.
%. Selectivity to HCN is calculated using the following formula
S.sub.HCN=[HCN].sub.OUT/([CO].sub.OUT+[CO2].sub.OUT+[HCN].sub.OUT+2*[PN]-
.sub.OUT)*100%
where [CO].sub.OUT, [CO2].sub.OUT, [HCN].sub.OUT and [PN].sub.OUT
are concentrations (vol. %) in the reactor effluent. The results of
the tests are shown in FIG. 8.
Example 22 (HCN and ACN Production from EtOH Ammoxidation)
[0266] E12 catalyst was tested at temperatures ranging from 350 to
500.degree. C. at W/F=0.2 (gs)/ml. The composition of the feed was
O.sub.2 (9.6 vol. %), NH.sub.3 (6.17 vol. %), EtOH (7 vol. %). EtOH
conversion was calculated using the following formula
X.sub.EtOH=(1-[EtOH].sub.OUT/[EtOH].sub.IN)*100%
where [EtOH].sub.IN is the concentration of EtOH in the feed in
vol. %, and [EtOH].sub.OUT is the concentration of EtOH in the
effluent in vol. %. Selectivity to HCN and ACN is calculated using
the following formulas
S.sub.HCN=([HCN].sub.OUT/([CO].sub.OUT+[CO2].sub.OUT+[HCN].sub.OUT+2*[AC-
N].sub.OUT))*100%
S.sub.ACN=([ACN].sub.OUT/([EtOH].sub.IN-[EtOH].sub.OUT)*100%
where [CO].sub.OUT, [CO2].sub.OUT, [HCN].sub.OUT and [ACN].sub.OUT
are concentrations (vol. %) in the reactor effluent. The results of
the tests are shown in FIG. 9. The results showed that EtOH is
being converted to HCN and ACN.
Example 23 (HCN and ACN Production from Acetone Ammoxidation)
[0267] E12 catalyst was tested at temperatures ranging from 350 to
475.degree. C. at W/F=0.2 (gs)/ml. The composition of the feed was
O.sub.2 (9.6 vol. %), NH.sub.3 (6.10 vol. %), and acetone (5.1 vol.
%). Acetone conversion was calculated using the following
formula
X.sub.Acetone=(1-[Acetone].sub.OUT/[Acetone].sub.IN)*100%
where [Acetone].sub.IN is the concentration of Acetone in the feed
in vol. %, and [Acetone].sub.OUT is the concentration of Acetone in
the effluent in vol. %. Selectivity to HCN and ACN is calculated
using the following formulas
S.sub.HCN=([HCN].sub.OUT/([CO].sub.OUT+[CO2].sub.OUT+[HCN].sub.OUT+2*[AC-
N].sub.OUT))*100%
S.sub.ACN=2*[ACN].sub.OUT/([CO].sub.OUT+[CO2].sub.OUT+[HCN].sub.OUT+2*[A-
CN].sub.OUT)*100%
where [CO].sub.OUT, [CO2].sub.OUT, [HCN].sub.OUT and [ACN].sub.OUT
are concentrations (vol. %) in the reactor effluent; ACN stands for
acetonitrile. No products other than CO, CO.sub.2, ACN and HCN were
observed. The results of the tests are shown in FIG. 10. The
results showed that acetone is being converted to HCN and ACN.
Results
[0268] The catalyst compositions of the present invention
effectively convert unconverted NH.sub.3 and O.sub.2 present in a
simulated AN reactor effluent stream to value-added product HCN,
which is illustrated in FIG. 1 as in-line processing of the
invention, and eliminate the need for the conventional process of
NH.sub.3 removal via acid neutralization. As described herein, the
catalyst compositions and the ammoxidation process of the present
invention can also be used to increase HCN and nitrile products,
such as ACN in the AN reactor effluent via the introduction of
alcohols such as EtOH and/or nitriles and/or ketones
ammoxidation.
[0269] As can be seen from FIG. 3 and Table 1, the novel catalyst
compositions of the present invention exhibit higher CH.sub.3OH and
NH.sub.3 conversions, and HCN selectivity and yield under
CH.sub.3OH ammoxidation conditions compared to similar comparative
catalyst compositions. A continued DOE approach or similar
methodology as shown in FIG. 2 beyond the elemental composition
ranges listed in Table 5 of the conducted DOE studies or any
additional modifications and variations to the composition in Table
5 could be made thereto without departing from the scope of the
present invention. FIGS. 4A and 4B show comparable CH.sub.3OH
conversions and HCN yields at both high and low Mo/Fe molar ratios,
indicating the molybdenum usage from various source compounds may
be further optimized and/or varied to achieve improved
performance.
TABLE-US-00005 TABLE 5 Elemental composition ranges of DOE studies
Element Minimum at Fe = 1 Maximum at Fe = 1 Mo 2.17 47.97 Bi 0.127
0.127 Cr 0.074 0.074 Fe 1 1 Ni 0 2.89 Cu 0 2.89 Zn 0 2.89 Co 0 2.89
Mn 0 0.26 Sn 0 1.22 Sb 0 0.76 Gd 0 2.00 Mg 0 1.17 Re 0 0.26 Ce 0
2.81 Ru 0 1.00 Ti 0 14.64 Zr 0 6.39 Al 0 12.73 Si 0 47.22
[0270] Table 2 illustrates that an unsupported catalyst provides
high HCN yield and supports incorporation such as TiO.sub.2 and
high surface area SiO.sub.2 into the catalyst to further increase
CH.sub.3OH conversion and HCN yield. Therefore, the catalysts of
the present invention can perform with or without a support. If
needed, suitable supports include, but are not limited to, silica,
zirconia, titania, alumina and mixtures thereof.
[0271] An optimization study is illustrated in FIG. 5 in which
CH.sub.3OH conversion increases with increasing temperature but HCN
selectivity remains almost unchanged from 350 to 425.degree. C. A
maximum yield of HCN is unexpectedly achieved at 425.degree. C.
Similarly, other reaction conditions, such as pressure, space
velocity, linear velocity, and residence time can also be optimized
to achieve higher product yields from ammoxidation processing of
alcohols and/or nitriles to HCN, ACN, and/or to corresponding
nitriles employing the catalyst compositions of the present
invention.
[0272] The CH.sub.3OH and NH.sub.3 usage efficiencies as shown in
in FIG. 6 clearly indicate a linear correlation between CH.sub.3OH
conversion and NH.sub.3 conversion, nearly a 1:1 reaction
efficiency. In addition to observed high HCN selectivity, low
energy consumption (due to hot effluent transferring heat to the
process in the invention), and ammonia sulfate waste avoidance, the
catalyst compositions of the present invention promote a high
material usage efficiency, low energy and an environmentally benign
ammoxidation process.
[0273] Table 3 indicates that AN burnings are negligible in the
fixed-bed catalytic monolith reactor using the catalyst of the
present invention. AN burning or destruction is not desirable in
the CH.sub.3OH ammoxidation process of the present invention as
described above. The results clearly indicate that an AN product
present in the AN production reactor effluent was not destroyed,
burned, and/or damaged in the subsequent CH.sub.3OH ammoxidation
process of the present invention. Additionally, NH.sub.3 present in
the NH.sub.3/AN/O.sub.2/N.sub.2 feed is fully (100%) converted to
N.sub.2 at 405.degree. C. and 430.degree. C. in the absence of
CH.sub.3OH. These interesting results indicate that the catalysts
of the present invention can completely oxidize NH.sub.3 to N.sub.2
without burning AN present in the feed. Practically speaking, the
catalysts of the present invention can convert unconverted NH.sub.3
in the AN reactor effluent to N.sub.2 without burning AN present in
the feed, thus avoiding the unconverted NH.sub.3 neutralization by
acid and subsequent separation and disposal as conventionally
practiced. Furthermore, NH.sub.3 present in the
NH.sub.3/O.sub.2/N.sub.2 feed is also fully (100%) converted to
N.sub.2 at 398.degree. C. in the absence of CH.sub.3OH and AN.
These results suggest that the catalyst compositions of the present
invention can also completely and selectively oxidize NH.sub.3 to
only N.sub.2 in O.sub.2/N.sub.2, an oxygen-rich environment. As
such, the catalysts of the present invention can also be employed
in the removal of NH.sub.3 from industrial effluents such as mobile
exhaust sources (including automobiles and trucks) and stationary
exhaust sources (including power plants) at a significantly lower
cost than existing noble metal catalysts, such as Pt-based
catalysts. In addition to negligible AN burning using the
catalyst-coated monolith as shown in Table 3, the results of using
catalyst powder, illustrated in Table 4 not only confirm the lack
of detectable amounts of AN burning but also reveal that the
CH.sub.3OH conversion and HCN selectivity and yield are almost
unchanged and/or not impacted by AN present in the feed.
[0274] The results shown in FIG. 7 depict high CH.sub.3OH
conversion and unexpectedly high (close to 100%) HCN selectivity at
any temperature between 325.degree. C. to 450.degree. C. This
observation illustrates the fact that high catalyst activity and
high HCN selectivity is unexpected and could not have been
predicted by those skilled in the art. As shown in FIGS. 8-10, the
HCN and HCN/ACN can be produced from propionitrile (PN), EtOH, and
acetone ammoxidation, respectively, using the catalysts of the
present invention. The HCN selectivity from PN and the HCN/ACN
selectivity from EtOH and acetone ammoxidation are acceptable but
can be further increased via optimization of the catalyst
compositions and the testing conditions. The relative amounts of
HCN and ACN can be controlled by the process of the present
invention as shown in FIG. 1 via using a mixture of alcohols with
varying ratios of CH.sub.3OH to EtOH. An increase in HCN and ACN
production during the production of AN can be achieved using
alcohol mixtures. In further similarly conducted tests, the
ammoxidation of alcohols and/or nitriles and/or ketones to HCN
and/or to corresponding nitriles can be achieved using the catalyst
compositions and/or processes of the present invention.
[0275] In addition to unconverted NH.sub.3 and/or O.sub.2 present
in an effluent stream of a primary AN reactor, there are also
additional components, such as PN, ACN, acrolein, and
methacrylonitrile, present as process by-products. AN burning is
negligible in multiple exemplary embodiments. PN reacted with
NH.sub.3 in Example 21 to produce HCN suggests that additional
components in the reactor effluent are capable of reacting with
unconverted NH.sub.3 and/or O.sub.2 to produce additional HCN
and/or nitriles in the presence of the catalyst compositions of the
present invention in the secondary reactor outside the primary AN
reactor. These additional organic compound components, present as
by-products from primary ammoxidation reactor effluent, can also be
provided independently. Additional organic compound components
include propane present as an impurity of a propylene feed or as a
co-feed with propylene to a primary AN reactor. This unconverted
propane and/or propylene can react with unconverted NH.sub.3 and/or
O.sub.2 to produce additional HCN and AN in the presence of the
catalyst compositions of the present invention and/or suitable
ammoxidation catalysts in the secondary reactor outside the primary
AN reactor. These additional components present in an unconverted
feed such as propylene/propane and isobutylene/isobutane from a
primary ammoxidation reactor effluent can also be provided
independently. Therefore, when CH.sub.3OH is injected into the
secondary reactor outside the primary ammoxidation reactor, the
unconverted NH.sub.3 and/or O.sub.2 react with both the injected
CH.sub.3OH and with any additional organic compound components
present in the ammoxidation reactor effluent (or provided
independently) to produce additional HCN and nitriles. When an
alcohol or alcohol-containing mixture, a nitrile or
nitrile-containing mixture, a ketone or ketone-containing mixture,
an aldehyde or aldehyde-containing mixture, a carboxylic acid or
carboxylic acid-containing mixture, an ester or ester-containing
mixture, an ether or ether-containing mixture, their derivatives,
or mixtures thereof is injected into the secondary reactor, the
unconverted NH.sub.3 and/or O.sub.2 present in an effluent stream
of the primary ammoxidation reactor react with both (i) injected
organic compound components and (ii) any additional organic
compound components (such as unconverted alkanes, alkenes,
aromatics, alcohols, aldehydes, their derivatives, including
nitriles and/or mixtures thereof) present in the reactor effluent
(or provided independently) to produce additional HCN and
nitriles.
[0276] Although the present invention has been disclosed in terms
of selected embodiments, it will be apparent to one of ordinary
skill in the art that changes and modifications may be made to the
invention without departing from its spirit or scope as set forth
herein. All patents and other publications referred to herein are
incorporated by reference in their entireties.
* * * * *