U.S. patent application number 13/875358 was filed with the patent office on 2013-09-19 for catalyst for producing n-substituted carbamates, and the preparation and application of the same.
This patent application is currently assigned to Bayer MaterialScience AG. The applicant listed for this patent is Maoquing Kang, Stephan Klein, Hongchao Li, Qifeng Li, Xinkui Wang, Stefan Wershofen. Invention is credited to Maoquing Kang, Stephan Klein, Hongchao Li, Qifeng Li, Xinkui Wang, Stefan Wershofen.
Application Number | 20130244867 13/875358 |
Document ID | / |
Family ID | 43049464 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130244867 |
Kind Code |
A1 |
Wershofen; Stefan ; et
al. |
September 19, 2013 |
CATALYST FOR PRODUCING N-SUBSTITUTED CARBAMATES, AND THE
PREPARATION AND APPLICATION OF THE SAME
Abstract
The present invention relates to a novel catalyst for producing
N-substituted carbamates, the preparation of the catalyst and an
improved method for producing N-substituted carbamates from these
novel catalysts. The active component of the catalyst is a
heteropoly acid and the catalyst support comprises a metal oxide or
a metalloid oxide. The catalyst can be used to promote the reaction
of carbamate and amine, thereby generating N-substituted carbamates
with high yield. In the presence of the catalyst, the reaction
conditions are relatively mild, the catalytic activity and
selectivity of the reaction are high, and the reaction time is
relatively short. Furthermore, the catalyst can be conveniently
separated from the reaction system and recycled, therefore, the
catalyst can be used to facilitate the further scale-up test and
commercial application.
Inventors: |
Wershofen; Stefan;
(Monchengladbach, DE) ; Klein; Stephan; (Shanghai,
CN) ; Li; Hongchao; (Pudong, CN) ; Wang;
Xinkui; (Shanxi, CN) ; Li; Qifeng; (Taiyuan,
CN) ; Kang; Maoquing; (Shanxi, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wershofen; Stefan
Klein; Stephan
Li; Hongchao
Wang; Xinkui
Li; Qifeng
Kang; Maoquing |
Monchengladbach
Shanghai
Pudong
Shanxi
Taiyuan
Shanxi |
|
DE
CN
CN
CN
CN
CN |
|
|
Assignee: |
Bayer MaterialScience AG
|
Family ID: |
43049464 |
Appl. No.: |
13/875358 |
Filed: |
May 2, 2013 |
Current U.S.
Class: |
502/210 ;
502/300; 502/353; 502/355 |
Current CPC
Class: |
C07C 269/06 20130101;
B01J 37/0201 20130101; B01J 23/22 20130101; B01J 35/1019 20130101;
B01J 35/1042 20130101; B01J 27/188 20130101; B01J 27/199 20130101;
B01J 21/04 20130101; B01J 35/1014 20130101; B01J 35/1038 20130101;
C07C 271/28 20130101; Y02P 20/584 20151101; C07C 269/06
20130101 |
Class at
Publication: |
502/210 ;
502/300; 502/355; 502/353 |
International
Class: |
B01J 27/199 20060101
B01J027/199; B01J 27/188 20060101 B01J027/188 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 2009 |
CN |
200910051496.4 |
Claims
1-12. (canceled)
13. A catalyst for preparing a N-substituted carbamate, wherein the
active component of the catalyst comprises a heteropoly acid and
the component of the catalyst support comprise a metal oxide or
metalloid oxide.
14. The catalyst of claim 13, wherein the heteropoly acid is a
Keggin type heteropoly acid.
15. The catalyst of claim 14, wherein the heteropoly acid is
selected from the group consisting of
H.sub.3PW.sub.12O.sub.40.nH.sub.2O,
H.sub.3PMo.sub.12O.sub.40.nH.sub.2O,
H.sub.4SiW.sub.12O.sub.40.nH.sub.2O and
H.sub.4SiMo.sub.12O.sub.40.nH.sub.2O.
16. The catalyst of claim 13, wherein the catalyst support
component comprising a metal oxide or a metalloid oxide is selected
from the group consisting of zirconium oxide, titanium oxide, zinc
oxide, silicon oxide, magnesium oxide, calcium oxide, tin oxide,
barium oxide, cerium oxide, lanthanum oxide, vanadium pentoxide,
aluminium oxide and mixtures thereof.
17. The catalyst of claim 16, wherein the metal oxide is selected
from the group consisting of a vanadium pentoxide, an aluminium
oxide and mixtures thereof.
18. The catalyst of claim 13, wherein the load of the active
component of the catalyst is from 0.1 to 20 wt. %, based on 100 wt.
% of the catalyst support.
19. A method for preparing the catalyst of claim 13, comprising (1)
impregnating (i) a catalyst support into (ii) a heteropoly acid
solution comprising one or more heteropoly acids to form a catalyst
precursor, and (2) calcinating said catalyst precursor at a
temperature of from 150 to 1000.degree. C. to obtain a
catalyst.
20. The method of claim 19, wherein said heteropoly acid is
selected from the group consisting of
H.sub.3PW.sub.12O.sub.40.nH.sub.2O, H.sub.3PMo.sub.12O.sub.40.
nH.sub.2O, H.sub.4SiW.sub.12O.sub.40.nH.sub.2O and
H.sub.4SiMo.sub.12O.sub.40.nH.sub.2O.
21. The method of claim 19, wherein said metal oxide or said
metalloid oxide is selected from the group consisting of zirconium
oxide, titanium oxide, zinc oxide, silicon oxide, magnesium oxide,
calcium oxide, tin oxide, barium oxide, cerium oxide, lanthanum
oxide, vanadium pentoxide, aluminium oxide and mixtures
thereof.
22. The method of claim 21, wherein said metal oxide is selected
from the group consisting of a vanadium pentoxide, an aluminium
oxide and mixtures thereof.
23. The method of claim 19, wherein the load of the active
component of the catalyst is from 0.1 to 20 wt. %, based on 100 wt.
% of the catalyst support.
24. The method of claim 19, additionally comprising a drying step
after (1) said impregnating step and before (2) said calcinating
step, wherein the temperature of the drying step is less than or
equal to 140.degree. C.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] The present patent application claims the right of priority
under 35 U.S.C. .sctn.119 (a)-(d) of Chinese Patent Application No.
200910051496.4, filed May 19, 2009.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to N-substituted carbamates,
and particularly to a catalyst for preparing these N-substituted
carbamates. This invention also relates to the novel catalyst, to
the preparation of the catalyst, and to the use thereof.
[0003] N-substituted carbamates represent a class of important
organic intermediates, which can be used for the manufacture of
agrochemicals, dyes, pharmaceuticals, ureas, and isocyanates.
Furthermore, they can also be applied as protective groups of
amides in various organic syntheses.
[0004] The synthesis of N-substituted carbamates has received
considerable attention due to their wide applications. For example,
U.S. Pat. No. 3,763,217 and U.S. Pat. No. 4,268,683 disclose the
synthesis of N-substituted carbamates by reacting aromatic amines
with organic carbonates in the presence of AlCl.sub.3, FeCl.sub.3,
UO.sub.2(NO).sub.2, zinc acetate, zinc propionate, or zinc
naphthenate as a catalyst, respectively. This method has low
selectivity for the desired products. Moreover, the catalyst
activity is restricted by the aromatic amines. Both DE 2943480 and
U.S. Pat. No. 4,381,403 disclose that homogeneous ZnCl.sub.2 or
tertiary amine can be used as a catalyst in the synthesis of
N-substituted carbamates by reacting carbamates and amines.
However, these catalysts are difficult to separate and recover from
the reaction mixtures. Thus, these catalyst can not be conveniently
recycled.
[0005] From the perspective of commercial application, it is
necessary to develop a new catalyst for preparing N-substituted
carbamates. The catalyst should not only be capable of preparing
the targeted products in high yields, but should also be convenient
to separate from the product and recycled.
SUMMARY OF THE INVENTION
[0006] One aspect of the present invention is to provide a method
for preparing N-substituted carbamates. In accordance with the
present invention, this method comprises reacting a carbamate with
an amine in the presence of a catalyst to form an N-substituted
carbamate, wherein the catalyst comprises a heteropoly acid as
active component and a metal oxide or a metalloid oxide as catalyst
support.
[0007] Another aspect of the present invention is to provide a
novel catalyst which is suitable for preparing N-substituted
carbamates. In accordance with the present invention, the catalyst
comprises an active component and a catalyst support component. The
active component of the catalyst is a heteropoly acid, and the
component of the catalyst support is a metal oxide or a metalloid
oxide.
[0008] The third aspect of the present invention is to provide a
method for preparing this catalyst. According to the present
invention, the method comprises (1) impregnating a catalyst support
into a heteropoly acid solution comprising one or more heteropoly
acids to form a catalyst precursor, and (2) calcinating the
catalyst precursor to obtain a catalyst, wherein the calcination
temperature ranges from 150 to 1000.degree. C.
[0009] In accordance with the present invention, N-substituted
carbamates can be prepared with high yield by reacting
N-unsttbstituted carbamates with amines in the presence of the
catalyst provided here. The reaction system can be easily scaled
up, due to the fact that the reaction conditions are relatively
mild, and the activity and selectivity of the catalyst are high,
and the reaction time is rather short. Furthermore, the catalyst
can be easily separated from the reaction system and recycled.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Heteropoly acids (HPAs) are commonly regarded as attractive
catalytic materials and are applied to a variety of reactions such
as, for example, dehydration, cyclization, esterification, and so
on. However, homogeneous HPAs are difficult to separate and recover
from the reaction mixture. Therefore, HPAs can not be conveniently
recycled.
[0011] The present invention provides a new catalyst comprising an
active component and a catalyst support component, with the active
component comprising a h.eteropoly acid, and the catalyst support
component comprising a metal oxide or a metalloid oxide. It has
been found that in the presence of such catalyst, carbamates react
with amines to form N-substituted carbamates in high yield. In
addition, the catalyst can be separated from the reaction system
and recycled easily. This makes commercial scale-up and application
commercially feasible.
[0012] A preferred embodiment of the catalyst is hat the catalyst
support component comprises vanadium pentoxide (V.sub.2O.sub.5). It
has been found that there is a synergistic action between
V.sub.2O.sub.5 as the catalyst support component, and Keggin type
HPAs as the active component of the catalyst, which further enhance
the selectivity and increase the yield of the reaction.
Catalyst for Preparing N-Substituted Carbamates
[0013] The active component of the catalyst of the present
invention is a Heteropoly acid (HPAs), preferably a Keggin type
Heteropoly acids (HPAs). More preferred Keggin type Heteropoly
acids include tungstophoric acid
(H.sub.3PW.sub.12O.sub.40.nH.sub.2O), molybdophosphoric acid
(H.sub.3PMo.sub.12O.sub.4.nH.sub.2O), tungstosilicic acid
(H.sub.4SiW.sub.12O.sub.40nH.sub.2O), molybdosilicic acid
(H.sub.4SiMo.sub.12O.sub.40.nH.sub.2O), or their mixtures. It is
most preferred that the Keggin type Heteropoly acid be selected
from the group consisting of tungstophosphoric acid
(H.sub.3PW.sub.12O.sub.40.nH.sub.2O), molybdophosphoric acid
(H.sub.3PMo.sub.12O.sub.40.nH.sub.2O) and mixtures thereof.
[0014] The catalyst of this invention also requires a catalyst
support component. This catalyst support component is a metal oxide
or a metalloid oxide. Preferably, the metal oxide or metalloid
oxide is selected from the group consisting of zirconia, titania,
zinc oxide, silica, magnesia, calcium oxide, stannic oxide, barium
oxide, cerium oxide, lanthanum oxide, vanadium pentoxide, alumina
and mixtures thereof. More preferably, the catalyst support
component is selected from the group consisting of vanadium
pentoxide, alumina and mixtures thereof Vanadium pentoxide is a
most preferred catalyst support component.
[0015] The average diameter of the catalyst support is preferably
(but not limited to) 0.1 to 4 mm, more preferably 0.5 to 3 mm, and
most preferably 1 to 2 mm.
[0016] The pore volume of the catalyst support is preferably (but
not limited to) 0.01 to 10 cm.sup.3/g, more preferably 0.1 to 1
cm.sup.3/g, most preferably 0.2 to 0.8 cm.sup.3/g, and most
particularly preferably 0.4 to 0.6 cm.sup.3/g.
[0017] The BET surface area of the catalyst support is preferably
(but not limited to) less than or equal to 300 m.sup.2/g, more
preferably from 1 to 250 m.sup.2/g, most preferably from 5 to 100
m.sup.2/g, and most particularly preferably from 10 to 60
m.sup.2/g.
[0018] There are no special limitations with regard to the shape of
the catalyst. For example, the shape of the catalyst can be
spherical, cylindrical or irregular. The loading of the active
component can be preferably (but is not limited to) from 0.1 to 20%
by weight, more preferably from 1 to 10% by weight, and most
preferably from 4 to 7% by weight, based on 100% by weight of the
catalyst support.
Preparation of the Catalyst:
[0019] The method for preparing the catalyst comprises the steps of
impregnating and cal.cinating, etc. The method can additionally
include a drying step for the catalyst precursor after the
impregnating step and before the calcinating step. The temperature
of the drying step can be from (but is not limited to) less than or
equal to 140.degree. C., and more preferably from 90 to 120.degree.
C., The time of the drying step can be, but is not limited to, less
than or equal to 24 hours, more preferably less than or equal to 15
hours, and most preferably from 5 to 12 hours. There is no special
limitation with regard to the pressure in the drying step, however,
drying preferably occurs at 1 atm. The atmosphere of the drying
step can be selected from (but is not limited to) preferably air,
oxygen, nitrogen, etc. More preferably the atmosphere of the drying
step is air and/or oxygen, and is most preferably air.
[0020] In the impregnating step, one heteropoly acid or a mixture
of two or more heteropoly acids is dissolved in a solvent to form a
heteropoly acid solution. The heteropoly acid can be selected from
(but is not limited to) preferably tungstophosphoric acid
(H.sub.3PW.sub.12O.sub.40.nH.sub.2O) molybdophosphoric acid
(H.sub.3PMo.sub.12O.sub.40.nH.sub.2O), tungstosilicic acid
(H.sub.4SiW.sub.12O.sub.40.nH.sub.2O), molybdosilicic acid
(H.sub.4SiMo.sub.12O.sub.40.nH.sub.2O), or their mixtures; and most
preferably tungstophosphoric acid
(H.sub.3PW.sub.12O.sub.40.nH.sub.2O), molybdophosphoric acid
(H.sub.3PMo.sub.12O.sub.40.nH.sub.2O), or their mixtures. The
solvent can be selected from, but is not limited to, water, an
aqueous solvent, a non-aqueous solvent, or any mixture of the
aforementioned solvents. Suitable non-aqueous solvent can be
selected from, preferably, ethers, alcohols, ketones, nitriles or
amides; more preferably, diethyl ether, methanol, ethanol,
propanol, butyl alcohol, acetone, butanonc, acetonitrile, dimethyl
sulfone, dimethyl sulfoxide or dimethylformamide.
[0021] The pH value of the aqueous solution comprising the
precursor of the catalytically active component can be adjusted
through the addition of hydrated or non-hydrated acids. The
hydrated or non-hydrated acids can be selected from, but are not
limited to, HCl, HNO.sub.3, H.sub.2SO.sub.4, H.sub.3PO.sub.4 or
CH.sub.3COOH.
[0022] The catalyst precursor is obtained by impregnating a
catalyst support into a solution containing the heteropoly acids.
The component of the catalyst support is a metal oxide or a
metalloid oxide. The metal oxide or metalloid oxide acids can be
selected from, but is not limited to, preferably zirconia, titania,
zinc oxide, silica, magnesia, calcium oxide, stannic oxide, barium
oxide, cerium oxide, lanthanum oxide, vanadium pentoxide, alumina,
or their mixtures. More preferably, the metal oxide or metalloid
oxide acids are selected from vanadium pentoxide, alumina, or their
mixtures. Vanadium pentoxide is the most preferred metal oxide or
metalloid oxide acid.
[0023] There is no special limitation with regard to the
temperature of the impregnating step. Preferably impregnating
occurs at room temperature. The time of the impregnating step is
typically less than or equal to 20 hours, and preferably from 1 to
4 hours.
[0024] In the calcination step, the calcination temperature should
be high enough to result in the transformation of the catalyst
precursor to the catalyst. The calcination temperature can be from
preferably 200 to 1000.degree. C., more preferably from 300 to
700.degree. C. There is no special limitations with regard to the
calcination time. Preferably the time ranges from 1 to 20 hours,
and more preferably from 2 to 10 hours. The calcination step can be
carried out either in an inert atmosphere or in an oxidizing
atmosphere. The inert atmosphere can be selected from preferably
(hut is not limited to) a nitrogen gas, a noble gas, a
non-oxidizing gas, a non-reducing gas or a mixture of two or more
of the aforesaid gases. Nitrogen is more preferred as the inert
gas. The oxidizing atmosphere can be selected from preferably (but
is not limited to) oxygen gas or an oxygen containing gas, and more
preferably is an oxygen containing gas. The oxidizing atmosphere is
most preferably air. A mixture of air and nitrogen can be applied
as well.
Preparation of N-Substituted Carbamates (R'(NH--CO--OR).sub.n) in
the Presence of Said Catalyst:
[0025] One aspect of the present invention provides a method for
preparing N-substituted carbamates which correspond to the general
formula:
R'(NH--CO--OR).sub.n
[0026] This process comprises (1) reacting (a) one or more
N-unsubstantiated carbamates (H.sub.2N--CO--OR), with (b) one or
more amines, in the presence of (c) the novel catalyst described
herein. The reaction equation is:
nH.sub.2N--CO--OR+R'NH.sub.2).sub.n.fwdarw.R'(NH--CO--OR).sub.n+nNH.sub.-
3
[0027] The N-unsubstituted carbamates (H.sub.2N--CO--OR) can be
obtained via known synthetic routes such as the reaction between
urea and conesponding compound containing a hydroxyl group.
[0028] For the N-unsubstituted carbamates (H.sub.2N--CO--OR), R can
be selected from preferably, but is not limited to, [0029] a) a
branched or unbranched, substituted or unsubstituted aliphatic
group, which optionally contains one or more atoms different from C
and H; [0030] b) a branched or unbranched, substituted or
unsubstituted cycloaliphatic group, which optionally contains one
or more atoms different from C and H; [0031] c) a branched or
unbranched, substituted or unsubstituted araliphatic group, which
optionally contains one or more atoms different from C and H; or
[0032] d) a substituted or unsubstituted aromatic group, Which
optionally contains one or more atoms different from C and H.
[0033] In accordance with the above description, the atoms which
are different from C (carbon) and H (hydrogen) can preferably be
selected from the group consisting of, preferably, N, O, S. P, Si,
F, Cl, Br and I.
[0034] The branched or unbranched, substituted or unsubstituted
aliphatic group which optionally contains one or more atoms
different from C and H can preferably be selected from, for
example, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl,
tert-butyl, pentyl and its isomers, hexyl and its isomers,
2-methoxy-1-ethyl, 2-ethoxy-1-ethyl, 2-hydroxy-1-ethyl,
1-hydroxy-2-propyl, 2-hydroxy-1-propyl, 4-hydroxy-1-butyl, their
higher homologues or their isomers, their corresponding halogenated
groups. The halogenated groups can be selected from preferably, for
example, 2,2,2-triflouroethyl and
1,1,1,3,3,3-hexafluoro-2-propyl.
[0035] The branched or unbranched, substituted or unsubstituted
cycloaliphatic group which optionally contains one or more atoms
different from C and H can preferably be selected from, for
example, but is not limited to, cyclopentyl and cyclohexyl.
[0036] The branched or unbranched, substituted or unsubstituted
araliphatic group which optionally contains one or more atoms
different from C and H can preferably be selected from, for
example, but is not limited to, benzyl, 1-phenyl ethyl and 2-phenyl
ethyl.
[0037] The substituted or unsubstituted aromatic group wWhich
optionally contains one or more atoms different from C and H can
preferably be selected from, for example, but is not limited to,
phenyl, hydroxyphenyl or its isomers, methoxyphenyl or its isomers,
methylphenyl or its isomers, nitrophenyl or its isomers,
chlorophenyl or its isomers, fluorophenyl or its isomers,
bromophenyl or its isomers, iodophenyl or its isomers.
[0038] Suitable amines to be used in forming the N-substituted
carbamates can be selected from, for example, but are not limited
to, primary arnines and secondary amines. Primary amines are
preferred.
[0039] The primary amines can be characterized by the general
formula:
R'(NH.sub.2).sub.n,
[0040] wherein: [0041] n is 1, 2, or any integer more than 2;
[0042] R' can be selected from the following groups.
[0043] In accordance with the present invention, R is selected from
the groups: [0044] a) a branched or =branched, substituted or
unsubstituted aliphatic group which optionally contains one or more
atoms different from C and H; [0045] a branched or unbranched,
substituted or unsubstituted cycloaliphatic group which optionally
contains one or more atoms different from C and H; [0046] c) a
branched or unbranched, substituted or unsubstituted araliphatic
group which optionally contains one or more atoms different from C
and H; and [0047] d) a substituted or unsubstituted aromatic group
which optionally contains one or more atoms different from C and
H.
[0048] The above described R groups are not intended to be
limiting.
[0049] The branched or unbranched, substituted or =substituted
aliphatic primary amines which optionally contain one or more atoms
different from C and H can preferably be selected from, for
example, but are not limited to, methylamine, ethylamine,
propylamine or its isomers, butylamine or its isomers, pentylamine
or its isomers as well as their higher homologues, ethylene
diamine, 1,2-diaminopropane, .alpha.,.omega.-diaminoalkanes or its
isomers, substituted .alpha.,.omega.-diaminoalkanes or its isomers.
The .alpha.,.omega.-diaminoalkanes can be selected from preferably,
but are not limited to, 1,3-diaminopropane, 1,4-diaminobutane,
1,5-diaminopentane and 1,6 diaminohexane.
[0050] The branched or unhranched, substituted or unsubstituted
cycloaliphatic primary amines which optionally contains one or more
atoms different from C and H can preferably be selected from, for
example, but are not limited to, cyclohexylamine, cyclohexylainines
with substituted cycloaliphatic ring, diaminocyclohexane or its
isomers, diaminocyclohexanes with substituted cycloaliphatic ring,
isophorone diamine, 4,4'-diamino dicyclohexylmethane or its
isomers, 2,4'-diamino dicyclohexylmethane or its isomers,
2,2'-diamino dicyclohexylmethane or its isomers.
[0051] The branched or unbranched, substituted or unsubstituted
araliphatic primary amines which optionally contains one or more
atoms different from C and H can preferably be selected from, for
example, but are not limited to, benzylamine, 2-phenylethylamine,
1-phenylethylamine, o-xylylene diamine m-xylylene diamine,
p-xylylene diamine.
[0052] The substituted or unsubstituted aromatic primary amines
which optionally contains one or more atoms different from C and H
can preferably be selected from, for example, but are not limited
to, aniline, methoxyaniline or its isomers, toluidine or its
isomers, nitroaniline or its isomers, fluoroaniline or its isomers,
chloroaniline or its isomers, bromoaniline or its isomers,
iodoaniline or its isomers, o-phenylene diamine, m-phenylene
diamine, p-phenylene diamine, aromatic ring substituted phenylene
diamines, diaminotoluenes or its isomers, diamino diphenylmethane
or its isomers or homologues, naphthalene diamines or its isomers.
The aromatic ring substituted phenylene diamines can preferably be
selected from, for example, but are not limited to, tetramethyl
phenylene diamine. The diaminotoluenes or its isomers can
preferably be selected from, for example, but are not limited to,
2,4-diaminotoluene or 2,6-diaminotoluene. The isomer of diamino
diphenylmethane can preferably be selected from, for example, but
is not limited to, 4,4'-diamino diphenylmethane, 2,4'-diamino
diphenylmethane and 2,2'-diamino diphenylmethane. The isomer of
naphthalene diamines can preferably be selected from, for example,
but is not limited to, 1,4-naphthaline diamine, 1,5-naphthaline
diamine and 1,8-naphthaline diamine.
[0053] The substituted or unsubstituted aromatic primary amines
which optionally contains one or more atoms different from C and H
can also include a mixture of amines obtained by the condensation
reaction of aniline and formaldehyde, and the mixture comprises
diamino diphenylmethane or its isomers, polyfunctional amines of
the diphenylmethane series or its isomers or their higher
homologues,
[0054] In the present invention, the reaction can be run by using a
single amine, or a mixture of two or more of the aforementioned
amines.
[0055] In the present invention, the amounts of the raw materials
can be employed in such way that at least 1 mole of carbamate
(H.sub.2N--CO--OR) is employed for each mole of amino groups coming
from the primary amine R'(--NH.sub.2).sub.n; preferably from 1 to
30 moles of carbamate (H.sub.2N--CO--OR) are employed for each mole
of amino groups coming from the primary amine R'(--NH.sub.2).sub.n;
more preferably from 1- to 15 moles of carbamate (H.sub.2N--CO--OR)
are employed for each mole of amino groups coming from the primary
amine R'(--NH.sub.2).sub.n; and most preferably from 4 to 10 moles
of carbamate (H.sub.2N--CO--OR) are employed for each mole of amino
groups coming from the primary amine R'(--NH.sub.2).sub.n.
[0056] In the present invention, the process can be run either with
or without an additional solvent. In the latter case, the excess of
carbamate (H.sub.2N--CO--OR) serves as solvent.
[0057] When the reaction is conducted in the presence of additional
solvent, the additional solvent can be a single solvent or a
mixture of two or more solvents. The additional solvent can
preferably be selected from, for example, but is not limited to,
aliphatic or aromatic hydrocarbons or their halogenated
derivatives, polar solvents, and R--OH solvents. The aliphatic or
aromatic hydrocarbons or their halogenated derivatives can
preferably be selected from, for example, but are not limited to,
benzene, toluene, xylene or its isomers, ethylbenzene,
chlorobenzene, dichlorobenzene or its isomers. The polar solvents
can preferably be selected from, for example, but are not limited
to, acetone, butanone, dimethylformamide, dimethyl sulfone,
dimethyl sulfoxide, 1-octyl-3-methylimidazolium tetrafluoroborate
([C4-mim]BF.sub.4), 1-butyl-3-methylimidazolium tetrafluoroborate
([C4-mim]BF.sub.4), 1-butyl-3-methyl-imidazolium
tetrafluorophosphate ([bmim]BF.sub.4) or
1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]BF.sub.6).
The R--OH solvents having the same R. group as in the carbamates
(H.sub.2N--CO--OR) as reactant not only can facilitate the
reaction, but also can depress side-reactions and enhance product
selectivity. In the course of the process, a variety of
intermediates and/or byproducts can be formed, e.g. substituted
ureas based on the primary amines. The byproducts can be converted
partially or completely to carbamates by alcoholysis with the
hydroxyl component of R--OH. Generally, the molar ratio between
hydroxyl groups originating from the R--OH and amino groups
originating from the primary amine can preferably be selected from,
for example, but is not limited to, 1 to 100, more preferably 1 to
50, most preferably 1 to 10, and most particularly preferably 2 to
8.
[0058] The amount of catalyst employed is not critical, but shall
be sufficient to provide appropriate reaction rates. Preferably,
the amount of catalyst applied can preferably be selected from, for
example, but is not limited to, 20 parts by weight, more preferably
from 0.1 to 15 parts by weight, particularly preferably from 1 to
10 parts by weight, and most preferably from 3 to 8 parts by
weight, based on 100 parts by weight of the amine.
[0059] The reaction temperature can preferably be selected from,
for example, but is not limited to, greater than or equal to
100.degree. C., more preferably 100 to 300.degree. C., particularly
preferably 120 to 220.degree. C., and most preferably 140 to
200.degree. C. If the reaction temperature is too low, the reaction
rate might be reduced too much. If the reaction temperature is too
high, the risk of unwanted side reaction significantly reducing
yield and/or selectivity will increase.
[0060] The reaction time depends on other reaction conditions and
can be determined in orienting experiments. The reaction time is
preferably less than or equal to 24 hours, more preferably less
than or equal to 15 hours; further more preferably less than or
equal to 10 hours, particularly preferably from 2 to 10 hours, and
most preferably from 3 to 8 hours.
[0061] The reaction pressure is the autogenous pressure developing
at the chosen reaction temperature. Alternatively, the reaction
pressure can also be modified by adding a gas inert under the
reaction conditions, which can be selected from, but is not limited
to, a nitrogen gas, a noble gas, carbon dioxide, or mixtures of the
aforesaid gases. The reaction pressure can preferably be selected
from, for example, but is not limited to, 1 to 50 atm, more
preferably 1 to 30 atm, and most preferably 5 to 25 atm.
[0062] In the present invention, the catalyst can he employed in
fixed bed, fluidized bed or slurry reactor.
[0063] The reaction can be carried out continuously,
semi-continuously or batch-wise. The order of the addition of the
raw materials and/or of the catalyst to the reactor is not
critical, and the best way and/or most advantageous order to add
the material and catalyst can be determined in orienting
experiments. Furthermore, the ammonia formed during the reaction
can be removed from the reactor by appropriate means continuously
or intermittently to shift the reaction equilibrium to the product
side.
[0064] Appropriate reactors can preferably be selected from, for
example, but are not limited to, stirred reactors and tubular
reactors. The tubular reactors can preferably be selected from, for
example, but are not limited to, tubular reactors with or without
inserts, tubular reactors with or without mixing elements, tubular
reactors with or without redispersing elements, tubular reactors
with a combination of two or more members of the group including
inserts, mixing elements and redispersing elements.
[0065] In the reaction process, the starting materials,
intermediates, solvents and/or catalysts can be recovered and/or
recycled to any appropriate step of the reaction process.
[0066] After the reaction is finished, the reaction product can be
removed from the reactor. The process of work-up and/or product
isolation can be achieved by means of any appropriate
technique/means/process step. The appropriate
technique/means/process step can be selected from, but is not
limited to, distillation, crystallization, filtration,
sedimentation, decantation, centrifugation, extraction, membrane
separation, or other means, or a combination of two or more of the
aforesaid techniques/means.
[0067] In the process of the reaction or after the reaction is
finished, the catalyst can be recovered and/or recycled by means of
any appropriate technique/means/process step. The appropriate
technique/means/process step can preferably be selected from, for
example, but is not limited to, distillation, crystallization,
filtration, sedimentation, decantation, centrifugation, extraction,
membrane separation, or other means or by a combination of two or
more of the aforesaid techniques/means.
[0068] The catalyst can be recycled either without any further
treatment or after an appropriate reconditioning or treatment step,
including, but not limited to, separating the catalyst, washing the
catalyst thoroughly with an appropriate solvent, drying, or a
combination of two or more of the aforesaid techniques/means.
Drying can be performed in virtue of various manners such as, for
example, but not limited to, vacuum drying, microwave drying,
ultrasonic drying, supercritical fluid drying or a combination of
two or more of the aforesaid techniques/means.
EXAMPLES
[0069] The synthesis reactions were carried out in a stainless
steel autoclave with inner volume of 100 cm.sup.3. The starting
materials and catalyst were charged into the reactor. By flushing
the reactor with N.sub.2, the air in the autoclave was replaced.
Thereafter, the reactor was heated to the desired temperature for a
defined period of time as indicated in the examples. At the end of
the reaction, the resultant products were analyzed either by gas
chromatography (GC) or by liquid chromatography (LC), depending on
the choice of the starting material, the identification of the
products was performed by "liquid chromatography-mass spectrometry"
(LC-MS). Yields of products were calculated based on the weight of
aromatic amine used.
Preparation of Catalyst:
Example 1
[0070] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD (X-Ray Diffraction). The BET surface area of the
V.sub.2O.sub.5 was about 40 m.sup.2/g, and the pore volume of the
V.sub.2O.sub.5 was 0.4 cm.sup.3/g.
[0071] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 5 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5. After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere. After drying, the catalyst precursor was
calcinated at 450.degree. C. for 4 hours. The resulting catalyst
was named catalyst A.
Example 2
[0072] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD. The BET surface area of the V.sub.2O.sub.5 was
about 40 m.sup.2/g, and the pore volume of the V.sub.2O.sub.5 was
0.4 cm.sup.3/g.
[0073] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 1 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5. After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere, and then calcinated at 450.degree. C. for
4 hours. The resulting catalyst was named catalyst B.
Example 3
[0074] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD. The BET surface area of the V.sub.2O.sub.5 was
about 40 m.sup.2/g, and the pore volume of the V.sub.2O.sub.5 was
0.4 cm.sup.3/g.
[0075] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 15 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5 After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere. The dried catalyst precursor was then
calcinated at 450.degree. C. for 4 hours. The resulting catalyst
was named catalyst C.
Example 4
[0076] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD. The BET surface area of the V.sub.2O.sub.5 was
about 40 m.sup.2/g, and the pore volume of the V.sub.2O.sub.5 was
0.4 cm.sup.3/g.
[0077] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 5 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5. After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere, thereafter, calcined at 250.degree. C. for
4 hours. The resulting catalyst was named catalyst D.
Example 5
[0078] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD. The BET surface area of the V.sub.2O.sub.5 was
about 40 m.sup.2/g, and the pore volume of the V.sub.2O.sub.5 was
0.4 cm.sup.3/g.
[0079] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 5 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5. After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere, and thereafter, calcinated at 650.degree.
C. for 4 hours. The resulting catalyst was named catalyst E.
Example 6
[0080] V.sub.2O.sub.5 of analytically pure grade was used as a
catalyst support. Phase composition of the V.sub.2O.sub.5 was
confirmed by XRD. The BET surface area of the V.sub.2O.sub.5 was
about 40 m.sup.2/g, and the pore volume of the V.sub.2O.sub.5 was
0.4 cm.sup.3/g.
[0081] The catalyst was prepared by impregnating V.sub.2O.sub.5
into a solution containing 5 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the V.sub.2O.sub.5. After being impregnated for 4 hours, the
obtained catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere, thereafter, calcinated at 450.degree. C.
for 2 hours. The resulting catalyst was named catalyst F.
Example 7
[0082] .gamma.-Alumina of analytically pure grade was used as a
catalyst support. Phase composition of the .gamma.-Alumina was
confirmed by XRD. The BET surface area of the .gamma.-Alumina was
about 230 m.sup.2/g, and the pore volume of the .gamma.-Alumina was
0.65 cm.sup.3/g.
[0083] The catalyst was prepared by impregnating .gamma.-Alumina
into a solution containing 5 wt % H.sub.3PW.sub.12O.sub.40. The
volume of the impregnation solution corresponded to the volume of
the .delta.-Alumina. After being impregnated for 4 hours, the
resultant catalyst precursor was dried at 120.degree. C. for 12
hours in air atmosphere, thereafter, calcinated at 450.degree. C.
for 2 hours. The resulting catalyst was named catalyst G.
Preparation of N-Substituted Carbamates (R'(NH--CO--OR).sub.n):
Example 8
[0084] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0085] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 91.8%, 88.3% and 81.1%,
respectively.
Example 9
[0086] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst B (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0087] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 91.0%, 85.7% and 78.0%,
respectively.
Example 10
[0088] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst C (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0089] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 90.3%, 86.9% and 78.5%,
respectively.
Example 11
[0090] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst D (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0091] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 85.4%, 78.5% and 67.0%,
respectively.
Example 12
[0092] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst E (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0093] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 82.5%, 81.5% and 67.1%,
respectively.
Example 13
[0094] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst F (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0095] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 88.2%, 80.2% and 70.7%,
respectively.
Example 14
[0096] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0097] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor.
[0098] In order to check the reusability of the catalyst, the
reaction step as described above was repeated five times.
Therefore, after each run the catalyst A was separated from the
reaction mixture by filtration, washed with methanol, dried at
120.degree. C. for 12 hours and charged back into the reactor for
the next run. After completion of the 5 repeated runs, the yield of
O-methyl N-phenyl carbamate (MPC) was analyzed by gas
chromatography. The aniline conversion, MPC selectivity and MPC
yield were 88.5%, 82.7% and 73.2%, respectively.
Example 15
[0099] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.30 g catalyst A (3.16 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0100] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 85.7%, 82.4% and 70.6%,
respectively.
Example 16
[0101] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.90 g catalyst A (9.48 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0102] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 92.3%, 89.1% and 82.2%,
respectively.
Example 17
[0103] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0104] The reaction was performed at 140.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 60.1%, 72.4% and 43.5%,
respectively.
Example 18
[0105] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0106] The reaction was performed at 180.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 83.8%, 77.3% and 64.8%,
respectively.
Example 19
[0107] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0108] The reaction was performed at 160.degree. C. for 2 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 80.6%, 78.5% and 63.3%,
respectively.
Example 20
[0109] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0110] The reaction was performed at 160.degree. C. for 6 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 92.5%, 85.4% and 79.0%,
respectively.
Example 21
[0111] 9.50 g aniline, 60.00 g methyl carbamate, 3.25 g methanol
(molar ratio of aniline., methyl carbamate and methanol was 1:8:1),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0112] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 95.3%, 83.6% and 79.7%,
respectively.
Example 22
[0113] 9.50 g aniline, 60.00 g methyl carbamate, 32.50 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:10),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0114] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 82.4%, 92.4% and 76.1%,
respectively.
Example 23
[0115] 9.50 g aniline, 15.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:2:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0116] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 66.5%, 70.8% and 47.1%,
respectively.
Example 24
[0117] 9.50 g aniline, 75.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:10:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0118] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 92.6%, 89.1% and 82.5%,
respectively.
Example 25
[0119] 9.50 g aniline, 71.27 g ethyl carbamate, 23.04 g ethanol
(molar ratio of aniline, ethyl carbamate and ethanol was 1:8:5),
and 0.60 g catalyst A (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0120] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-ethyl N-phenyl carbamate (EPC) was
analyzed by gas chromatography. The aniline conversion, EPC
selectivity and EPC yield were 82.6%, 79.3% and 65.5%,
respectively.
Example 26
[0121] 9.50 g aniline, 93.72 g n-butyl carbamate, 37.06 g n-butanol
(molar ratio of aniline, n-butyl carbamate and n-butanol was
1:8:5), and 0.60 g catalyst A (6.32 parts by weight, based on 100
parts by weight of aniline) were charged into the reactor.
[0122] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-n-butyl N-phenyl carbamate (BPC) was
analyzed by gas chromatography. The aniline conversion, BPC
selectivity and BPC yield were 50.1%, 75.0% and 37.6%,
respectively.
Example 27
[0123] 12.22 g 2,4-toluene diamine, 60.00 g methyl carbamate, 16.25
g methanol (molar ratio of 2,4-toluene diamine, methyl carbamate
and methanol was 1:8:5), and 0.60 g catalyst A (6.32 parts by
weight, based on 100 parts by weight of aniline were charged into
the reactor.
[0124] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of corresponding biscarbamate was analyzed
by gas chromatography. The toluene diamine conversion, selectivity
and yield of the corresponding biscarbamate were 40.1%, 76.6% and
30.7%, respectively.
Example 28
[0125] 9.50 g aniline, 60.00 g methyl carbamate, 16.25 g methanol
(molar ratio of aniline, methyl carbamate and methanol was 1:8:5),
and 0.60 g catalyst G (6.32 parts by weight, based on 100 parts by
weight of aniline) were charged into the reactor.
[0126] The reaction was performed at 160.degree. C. for 4 hours
under autogenous pressure. The ammonia formed during the reaction
was continuously removed from the reactor. After the completion of
the reaction, the yield of O-methyl N-phenyl carbamate (MPC) was
analyzed by gas chromatography. The aniline conversion, MPC
selectivity and MPC yield were 74.3%, 72.5% and 53.9%,
respectively.
[0127] Although the present invention is illustrated through
Examples, it is not limited by these Examples in any way. Without
departing from the spirit and scope of this invention, those
skilled in the art can make any modifications and alternatives. And
the protection of this invention is based on the scope defined by
the claims of this application.
* * * * *