U.S. patent application number 15/741030 was filed with the patent office on 2018-07-05 for cyclohexanone compositions and processes for making such compositions.
The applicant listed for this patent is ExxonMobil Chemical Patents Inc.. Invention is credited to Medrado M. Leal, Ashley J. Poucher, Jorg F.W. Weber.
Application Number | 20180186715 15/741030 |
Document ID | / |
Family ID | 56373110 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180186715 |
Kind Code |
A1 |
Poucher; Ashley J. ; et
al. |
July 5, 2018 |
Cyclohexanone Compositions and Processes for Making Such
Compositions
Abstract
Disclosed are novel cyclohexanone compositions, and processes
for making such cyclohexanone compositions, from a mixture
comprising phenol, cyclohexanone, and cyclohexylbenzene. Such
cyclohexanone compositions comprise at least 99 wt % cyclohexanone,
at most 0.15 wt % water, and at most 500 wppm combined of certain
cyclohexanone impurities selected from the group consisting of:
benzene, cyclohexene, pentanal, cyclopentanol, cyclohexanol, and
phenol.
Inventors: |
Poucher; Ashley J.;
(Houston, TX) ; Weber; Jorg F.W.; (Houston,
TX) ; Leal; Medrado M.; (El Lago, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Chemical Patents Inc. |
Baytown |
TX |
US |
|
|
Family ID: |
56373110 |
Appl. No.: |
15/741030 |
Filed: |
June 16, 2016 |
PCT Filed: |
June 16, 2016 |
PCT NO: |
PCT/US2016/037802 |
371 Date: |
December 29, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62198470 |
Jul 29, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 45/53 20130101;
C07C 2601/14 20170501; C07C 45/006 20130101; C07C 49/543 20130101;
C07C 45/82 20130101; C07C 45/53 20130101; C07C 49/403 20130101;
C07C 45/006 20130101; C07C 49/403 20130101; C07C 45/82 20130101;
C07C 49/403 20130101 |
International
Class: |
C07C 49/543 20060101
C07C049/543 |
Claims
1. A cyclohexanone composition comprising: (a) at least 99 wt %
cyclohexanone; (b) 0.15 wt % or less water; (c) 0 to 10 wppm
benzene; (d) 5 to 10 wppm cyclohexene; (e) 0 to 10 wppm pentanal;
(f) 0 to 50 wppm cyclopentanol; and (g) 10 wppm to 40 wppm
cyclohexanol; wherein the wt % and wppm are each based upon total
weight of the cyclohexanone composition.
2. The cyclohexanone composition of claim 12, comprising at least
99.9 wt % cyclohexanone and at most 0.05 wt % water, based upon the
total weight of the cyclohexanone composition.
3. The cyclohexanone composition of claim 1, comprising 1 wppm to
10 wppm pentanal, based upon the total weight of the cyclohexanone
composition.
4. The cyclohexanone composition of claim 3, comprising 10 wppm to
50 wppm cyclopentanol, based upon the total weight of the
cyclohexanone composition.
5. The cyclohexanone composition of claim 1, comprising 10 wppm to
50 wppm cyclopentanol, based upon the total weight of the
cyclohexanone composition.
6. The cyclohexanone composition of claim 1, comprising 10 wppm to
20 wppm cyclohexanol.
7. The cyclohexanone composition of claim 1, wherein the
cyclohexanone composition consists of: (a) at least 99 wt %
cyclohexanone; (b) 0.15 wt % or less water; (c) 0 to 10 wppm
benzene; (d) 5 to 10 wppm cyclohexene; (e) 0 to 10 wppm pentanal;
(f) 0 to 50 wppm cyclopentanol; and (g) 10 wppm to 40 wppm
cyclohexanol; wherein the wt % and wppm are each based upon total
weight of the cyclohexanone composition.
8. The cyclohexanone composition of claim 7, wherein the
cyclohexanone is present at 99.9 wt % or greater, and further
wherein the water is present at 0.05 wt % or less, based upon the
total weight of the cyclohexanone composition.
9. The cyclohexanone composition of claim 7, wherein the pentanal
is present within the range of 1 to 10 wppm, based upon the total
weight of the cyclohexanone composition.
10. The cyclohexanone composition of claim 7, wherein the
cyclopentanol is present within the range of 10 to 50 wppm, based
upon the total weight of the cyclohexanone composition.
11. The cyclohexanone composition of claim 7, wherein the
cyclohexanol is present within the range of 10 wppm to 20 wppm,
based upon the total weight of the cyclohexanone composition.
12. A cyclohexanone composition consisting of: (a) at least 99 wt %
cyclohexanone; (b) 0.15 wt % or less water; and (c) 500 wppm or
less combined of one or more cyclohexanone impurities; wherein the
cyclohexanone impurities comprise pentanal, cyclopentanol, or both;
and further wherein the wt % and wppm are each based upon total
weight of the cyclohexanone composition.
13. The cyclohexanone composition of claim 12, wherein the
cyclohexanone impurities comprise pentanal and cyclopentanol.
14. The cyclohexanone composition of claim 12, wherein the
cyclohexanone impurities further comprise one or more of: benzene,
cyclohexene, cyclohexanol, and phenol.
15. The cyclohexanone composition of claim 12, wherein the
cyclohexanone impurities consist of: cyclohexene, pentanal,
cyclopentanol, and cyclohexanol.
16. The cyclohexanone composition of claim 12, comprising at least
99.9 wt % cyclohexanone, at most 0.05 wt % water, and 200 wppm or
less combined of the one or more cyclohexanone impurities.
Description
PRIORITY CLAIM
[0001] This invention claims priority to and the benefit of U.S.
Ser. No. 62/198,470 filed Jul. 29, 2015, which is incorporated by
reference herein.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application is related to U.S. Provisional Application
Ser. No. 62/140,702 filed Mar. 31, 2015; U.S. Provisional
Application Ser. No. 62/057,919 filed Sep. 30, 2014; and European
Application No. 15151424.7 filed Jan. 16, 2015, the disclosures of
which are fully incorporated herein by their reference.
FIELD OF THE INVENTION
[0003] The present invention relates to processes for making
cyclohexanone. In particular, the present invention relates to
processes for making cyclohexanone by phenol hydrogenation. The
present invention is useful, e.g., in making cyclohexanone from
cyclohexylbenzene oxidation and cyclohexylbenzene hydroperoxide
cleavage.
BACKGROUND OF THE INVENTION
[0004] Cyclohexanone is an important material in the chemical
industry and is widely used in, for example, production of phenolic
resins, bisphenol A, .epsilon.-caprolactam, adipic acid, and
plasticizers. One method for making cyclohexanone is by
hydrogenating phenol.
[0005] Currently, a common route for the production of phenol is
the Hock process. This is a three-step process in which the first
step involves alkylation of benzene with propylene to produce
cumene, followed by oxidation of cumene to the corresponding
hydroperoxide, and then cleavage of the hydroperoxide to produce
equimolar amounts of phenol and acetone. The separated phenol
product can then be converted to cyclohexanone by a step of
hydrogenation.
[0006] It is known from, e.g., U.S. Pat. No. 6,037,513, that
cyclohexylbenzene can be produced by contacting benzene with
hydrogen in the presence of a bifunctional catalyst comprising a
molecular sieve of the MCM-22 type and at least one hydrogenation
metal selected from palladium, ruthenium, nickel, cobalt, and
mixtures thereof. This reference also discloses that the resultant
cyclohexylbenzene can be oxidized to the corresponding
hydroperoxide, which can then be cleaved to produce a cleavage
mixture of phenol and cyclohexanone, which, in turn, can be
separated to obtain pure, substantially equimolar phenol and
cyclohexanone products. This cyclohexylbenzene-based process for
co-producing phenol and cyclohexanone can be highly efficient in
making these two important industrial materials. Given the higher
commercial value of cyclohexanone than phenol, it is highly
desirable that in this process more cyclohexanone than phenol be
produced. While this can be achieved by subsequently hydrogenating
the pure phenol product produced in this process to convert a part
or all of the phenol to cyclohexanone, a more economical process
and system would be highly desirable.
[0007] One solution to making more cyclohexanone than phenol from
the above cyclohexylbenzene-based process is to hydrogenate a
mixture containing phenol and cyclohexanone obtained from the
cleavage mixture to convert at least a portion of the phenol
contained therein to cyclohexanone. However, because the
phenol/cyclohexanone mixture invariably contains non-negligible
amounts of (i) catalyst poison component(s) (such as S-containing
components) that can poison the hydrogenation catalyst, and (ii)
cyclohexylbenzene that can be converted into bicyclohexane in the
hydrogenation step, and because hydrogenation of the
phenol/cyclohexanone/cyclohexylbenzene mixture can also lead to the
formation of cyclohexanol, resulting in yield loss, this process is
not without challenge.
[0008] Some references of potential interest in this regard may
include: U.S. Pat. Nos. 3,076,810; 3,322,651; 4,021,490; 4,439,409;
4,826,667; 4,954,325; 5,064,507; 5,168,983; 5,236,575; 5,250,277;
5,362,697; 6,037,513; 6,077,498; 6,730,625; 6,756,030; 7,199,271;
7,579,506; 7,579,511; and 8,921,603. Other references of potential
interest include WIPO Publication Nos. WO 97/17290; WO 2009/128984;
WO 2009/131769; WO 2009/134514; WO 2010/098916; WO 2012/036820; WO
2012/036822; WO 2012/036823; WO 2012/036828; WO 2012/036830; and WO
2014/137624. Further references of potential interest include EP 0
293 032; EP 0 606 553; and EP 1 575 892.
SUMMARY OF INVENTION
[0009] As such, there is a need for an improved process for making
cyclohexanone from a mixture containing phenol, cyclohexanone,
cyclohexylbenzene, and catalyst poison component(s).
Advantageously, such improved processes as described herein produce
cyclohexanone compositions that are novel, useful and very
different from those typically produced by conventional methods
(e.g., the conventional production of cyclohexanone via
hydrogenation of high purity phenol, and/or the oxidation of
cyclohexanol, and the like).
[0010] In particular, the present invention in some embodiments
provides a cyclohexanone composition comprising:
[0011] (a) at least 99 wt % cyclohexanone, by total weight of the
composition;
[0012] (b) 0.15 wt % or less water; and
[0013] (c) at most 500 wppm combined of one or more cyclohexanone
impurities selected from the group consisting of: benzene,
cyclohexene, pentanal, cyclopentanol, cyclohexanol, and phenol.
[0014] In certain of these embodiments, the composition comprises
two or more; three or more; or four or more of the aforementioned
cyclohexanone impurities. Such compounds may, e.g., be trace
impurities resulting from the particular process by which the
cyclohexanone composition is produced. In particular embodiments,
the cyclohexanone composition may comprise at least 99.9 wt %
cyclohexanone. Such compositions further comprise at most 0.05 wt %
water, and 500 ppm or less combined of cyclohexanone
impurities.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic diagram showing a process/system for
making cyclohexanone from a first mixture comprising phenol,
cyclohexanone and cyclohexylbenzene including a first distillation
column T1, a hydrogenation reactor R1, and a cyclohexanone
purification column T2.
[0016] FIG. 2 is a schematic diagram showing a portion of a
process/system similar to the process/system shown in FIG. 1, but
comprising modified fluid communications between and/or within the
first distillation column T1 and the hydrogenation reactor R1.
[0017] FIG. 3 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 and 2, but
comprising modified fluid communications and/or heat transfer
arrangement between and/or within the first distillation column T1
and the cyclohexanone purification column T2.
[0018] FIG. 4 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 3, but
comprising a tubular heat exchanger-type hydrogenation reactor R1,
where the hydrogenation reaction occurs primarily in vapor
phase.
[0019] FIG. 5 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 4, but
comprising three hydrogenation reactors R3, R5, and R7 connected in
series, where the hydrogenation reaction occurs primarily in liquid
phase.
[0020] FIG. 6 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 5, but
comprising modified fluid communications between and/or within the
first distillation column T1 and the hydrogenation reactor R1.
[0021] FIG. 7 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 6, but
comprising an anterior sorbent bed SBa before the first
distillation column T1 configured for removing at least a portion
of catalyst poison components from the
phenol/cyclohexanone/cyclohexylbenzene feed fed to the first
distillation column T1 to reduce or prevent catalyst poisoning in
the hydrogenation reactor.
[0022] FIG. 8 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 7, comprising a
posterior sorbent bed SBp after the first distillation column T1
configured for removing at least a portion of the S-containing
components from the phenol/cyclohexanone/cyclohexylbenzene feed fed
to the hydrogenation reactor to reduce or prevent catalyst
poisoning in the hydrogenation reactor.
[0023] FIG. 9 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 to 8, comprising a
sorbent bed T6 after the cyclohexanone purification column T2,
configured to reduce amounts of impurities (e.g., catalyst poison
components) from the final cyclohexanone product.
DETAILED DESCRIPTION
[0024] Various specific embodiments, versions and examples of the
invention will now be described, including preferred embodiments
and definitions that are adopted herein for purposes of
understanding the claimed invention. While the following detailed
description gives specific preferred embodiments, those skilled in
the art will appreciate that these embodiments are exemplary only,
and that the invention may be practiced in other ways. For purposes
of determining infringement, the scope of the invention will refer
to any one or more of the appended claims, including their
equivalents, and elements or limitations that are equivalent to
those that are recited. Any reference to the "invention" may refer
to one or more, but not necessarily all, of the inventions defined
by the claims.
[0025] In the present disclosure, a process is described as
comprising at least one "step." It should be understood that each
step is an action or operation that may be carried out once or
multiple times in the process, in a continuous or discontinuous
fashion. Unless specified to the contrary or the context clearly
indicates otherwise, each step in a process may be conducted
sequentially in the order as they are listed, with or without
overlapping with one or more other step, or in any other order, as
the case may be. In addition, one or more or even all steps may be
conducted simultaneously with regard to the same or different batch
of material. For example, in a continuous process, while a first
step in a process is being conducted with respect to a raw material
just fed into the beginning of the process, a second step may be
carried out simultaneously with respect to an intermediate material
resulting from treating the raw materials fed into the process at
an earlier time in the first step. Preferably, the steps are
conducted in the order described.
[0026] Unless otherwise indicated, all numbers indicating
quantities in the present disclosure are to be understood as being
modified by the term "about" in all instances. It should also be
understood that the precise numerical values used in the
specification and claims constitute specific embodiments. Efforts
have been made to ensure the accuracy of the data in the examples.
However, it should be understood that any measured data inherently
contain a certain level of error due to the limitation of the
technique and equipment used for making the measurement.
[0027] As used herein, the indefinite article "a" or "an" shall
mean "at least one" unless specified to the contrary or the context
clearly indicates otherwise. Thus, embodiments comprising "a light
component" include embodiments where one, two or more light
components exist, unless specified to the contrary or the context
clearly indicates that only one light component exists.
[0028] A "complex" as used herein means a material formed by
identified components via chemical bonds, hydrogen bonds, and/or
physical forces.
[0029] An "operation temperature" of a distillation column means
the highest temperature liquid media inside the column is exposed
to during normal operation. Thus, the operation temperature of a
column is typically the temperature of the liquid media in the
reboiler, if the column is equipped with a reboiler.
[0030] The term "S-containing component" as used herein includes
all compounds comprising sulfur.
[0031] In the present application, sulfur concentration in a
material is expressed in terms of proportion (ppm, weight
percentages, and the like) of the weight of elemental sulfur
relative to the total weight of the material, even though the
sulfur may be present in various valencies other than zero.
Sulfuric acid concentration is expressed in terms of proportion
(ppm, weight percentages, and the like) of the weight of
H.sub.2SO.sub.4 relative to the total weight of the material, even
though the sulfuric acid may be present in the material in forms
other than H.sub.2SO.sub.4. Thus, the sulfuric acid concentration
is the total concentration of H.sub.2SO.sub.4, SO.sub.3,
HSO.sub.4.sup.-, and R--HSO.sub.4 in the material.
[0032] As used herein, "wt %" means percentage by weight, "vol %"
means percentage by volume, "mol %" means percentage by mole, "ppm"
means parts per million, and "ppm wt" and "wppm" are used
interchangeably to mean parts per million on a weight basis. All
"ppm" as used herein are ppm by weight unless specified otherwise.
All concentrations herein are expressed on the basis of the total
amount of the composition in question. Thus, the concentrations of
the various components of the first mixture are expressed based on
the total weight of the first mixture. All ranges expressed herein
should include both end points as two specific embodiments unless
specified or indicated to the contrary.
[0033] In the present disclosure, a location "in the vicinity of"
an end (top or bottom) of a column means a location within 10% of
the top or bottom, respectively, the % being based upon the total
height of the column. That is, a location "in the vicinity of the
bottom" of a column is within the bottom 10% of the column's
height, and a location "in the vicinity of the top" of a column is
within the top 10% of the column's height.
[0034] An "upper effluent" as used herein may be at the very top or
the side of a vessel such as a distillation column or a reactor,
with or without an additional effluent above it. Preferably, an
upper effluent is drawn at a location in the vicinity of the top of
the column. Preferably, an upper effluent is drawn at a location
above at least one feed. A "lower effluent" as used herein is at a
location lower than the upper effluent, which may be at the very
bottom or the side of a vessel, and if at the side, with or without
additional effluent below it. Preferably, a lower effluent is drawn
at a location in the vicinity of the bottom of the column.
Preferably, a lower effluent is drawn at a location below at least
one feed. As used herein, a "middle effluent" is an effluent
between an upper effluent and a lower effluent. The "same level" on
a distillation column means a continuous segment of the column with
a total height no more than 5% of the total height of the
column.
[0035] Nomenclature of elements and groups thereof used herein are
pursuant to the Periodic Table used by the International Union of
Pure and Applied Chemistry after 1988. An example of the Periodic
Table is shown in the inner page of the front cover of Advanced
Inorganic Chemistry, 6.sup.th Edition, by F. Albert Cotton et al.
(John Wiley & Sons, Inc., 1999).
[0036] As used herein, the term "methylcyclopentanone" includes
both isomers 2-methylcyclopentanone (CAS Registry No. 1120-72-5)
and 3-methylcyclopentanone (CAS Registry No. 1757-42-2), at any
proportion between them, unless it is clearly specified to mean
only one of these two isomers or the context clearly indicates that
is the case. It should be noted that under the conditions of the
various steps of the present processes, the two isomers may undergo
isomerization reactions to result in a ratio between them different
from that in the raw materials immediately before being charged
into a vessel such as a distillation column.
[0037] As used herein, the generic term "dicyclohexylbenzene"
("DiCHB") includes, in the aggregate, 1,2-dicyclohexylbenzene,
1,3-dicylohexylbenzene, and 1,4-dicyclohexylbenzene, unless clearly
specified to mean only one or two thereof. The term
cyclohexylbenzene, when used in the singular form, means mono
substituted cyclohexylbenzene. As used herein, the term "C12" means
compounds having 12 carbon atoms, and "C12+ components" means
compounds having at least 12 carbon atoms. Examples of C12+
components include, among others, cyclohexylbenzene, biphenyl,
bicyclohexane, methylcyclopentylbenzene, 1,2-biphenylbenzene,
1,3-biphenylbenzene, 1,4-biphenylbenzene, 1,2,3-triphenylbenzene,
1,2,4-triphenylbenzene, 1,3,5-triphenylbenzene, and corresponding
oxygenates such as alcohols, ketones, acids, and esters derived
from these compounds. As used herein, the term "C18" means
compounds having 18 carbon atoms, and the term "C18+ components"
means compounds having at least 18 carbon atoms. Examples of C18+
components include, among others, dicyclohexylbenzenes ("DiCHB,"
described above), tricyclohexylbenzenes ("TriCHB," including all
isomers thereof, including 1,2,3-tricyclohexylbenzene,
1,2,4-tricyclohexylbenzene, 1,3,5-tricyclohexylbenzene, and
mixtures of two or more thereof at any proportion). As used herein,
the term "C24" means compounds having 24 carbon atoms.
[0038] As used herein, the term "light component" means compound
having a normal boiling point (i.e., boiling point at a pressure of
101,325 Pa) lower than cyclohexanone. Examples of the light
component include, but are not limited to: (i)
methylcyclopentanone; (ii) water; (iii) hydrocarbons comprising 4,
5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms, including but not
limited to linear, branched linear, cyclic, substituted cyclic,
alkanes, alkenes, and dienes; (iv) oxygenates such as alcohols,
aldehydes, ketones, carboxylic acids, ethers, and the like, of
hydrocarbons; (v) N-containing compounds, such as amines, amides,
imides, NO.sub.2-substituted compounds, and the like; (vi)
S-containing compounds, such as sulfides, sulfites, sulfates,
sulfones, and the like. It has been found that S-containing
compounds, N-containing compounds, dienes, alkenes, cyclic alkenes,
and cyclic dienes, and carboxylic acids comprising 1, 2, 3, 4, 5,
6, 7, or 8 carbon atoms can be present in the phenol/cyclohexanone
mixture produced by hydroperoxide cleavage reactions described in
greater detail below, and they can be particularly detrimental to
the performance of the hydrogenation catalyst, leading to catalyst
poisoning and undesirable, premature catalyst performance
reduction.
[0039] The term "MCM-22 type material" (or "material of the MCM-22
type" or "molecular sieve of the MCM-22 type" or "MCM-22 type
zeolite"), as used herein, includes one or more of: [0040]
molecular sieves made from a common first degree crystalline
building block unit cell, which unit cell has the MWW framework
topology. A unit cell is a spatial arrangement of atoms which if
tiled in three-dimensional space describes the crystal structure.
Such crystal structures are discussed in the "Atlas of Zeolite
Framework Types," Fifth Edition, 2001, the entire content of which
is incorporated as reference; [0041] molecular sieves made from a
common second degree building block, being a 2-dimensional tiling
of such MWW framework topology unit cells, forming a monolayer of
one unit cell thickness, desirably one c-unit cell thickness;
[0042] molecular sieves made from common second degree building
blocks, being layers of one or more than one unit cell thickness,
wherein the layer of more than one unit cell thickness is made from
stacking, packing, or binding at least two monolayers of one unit
cell thickness. The stacking of such second degree building blocks
can be in a regular fashion, an irregular fashion, a random
fashion, or any combination thereof; and [0043] molecular sieves
made by any regular or random 2-dimensional or 3-dimensional
combination of unit cells having the MWW framework topology.
[0044] Molecular sieves of the MCM-22 type include those molecular
sieves having an X-ray diffraction pattern including d-spacing
maxima at 12.4.+-.0.25, 6.9.+-.0.15, 3.57.+-.0.07, and 3.42.+-.0.07
Angstrom. The X-ray diffraction data used to characterize the
material are obtained by standard techniques such as using the
K-alpha doublet of copper as incident radiation and a
diffractometer equipped with a scintillation counter and associated
computer as the collection system.
[0045] Materials of the MCM-22 type include MCM-22 (described in
U.S. Pat. No. 4,954,325), PSH-3 (described in U.S. Pat. No.
4,439,409), SSZ-25 (described in U.S. Pat. No. 4,826,667), ERB-1
(described in European Patent No. 0293032), ITQ-1 (described in
U.S. Pat. No. 6,077,498), ITQ-2 (described in International Patent
Publication No. WO 97/17290), MCM-36 (described in U.S. Pat. No.
5,250,277), MCM-49 (described in U.S. Pat. No. 5,236,575), MCM-56
(described in U.S. Pat. No. 5,362,697), and mixtures thereof. Other
molecular sieves, such as UZM-8 (described in U.S. Pat. No.
6,756,030), may be used alone or together with the MCM-22 type
molecular sieves as well for the purpose of the present disclosure.
Desirably, the molecular sieve used in the catalyst of the present
disclosure is selected from (a) MCM-49; (b) MCM-56; and (c)
isotypes of MCM-49 and MCM-56, such as ITQ-2.
[0046] The process and systems for making cyclohexanone disclosed
herein can be advantageously used for making cyclohexanone from any
feed mixture comprising phenol, cyclohexanone and
cyclohexylbenzene. While the feed may be derived from any process
or source, it is preferably obtained from the acid cleavage of a
mixture comprising cyclohexylbenzene hydroperoxide and
cyclohexylbenzene, which, in turn, is preferably obtained from
aerobic oxidation of cyclohexylbenzene, which, in turn, is
preferably obtained from benzene hydroalkylation. Steps of these
preferred processes are described in detail below.
Supply of Cyclohexylbenzene
[0047] The cyclohexylbenzene supplied to the oxidation step can be
produced and/or recycled as part of an integrated process for
producing phenol and cyclohexanone from benzene. In such an
integrated process, benzene is initially converted to
cyclohexylbenzene by any conventional technique, including
oxidative coupling of benzene to make biphenyl followed by
hydrogenation of the biphenyl. However, in practice, the
cyclohexylbenzene is desirably produced by contacting benzene with
hydrogen under hydroalkylation conditions in the presence of a
hydroalkylation catalyst whereby benzene undergoes the following
Reaction-1 to produce cyclohexylbenzene (CHB):
##STR00001##
[0048] Alternatively, cyclohexylbenzene can be produced by direct
alkylation of benzene with cyclohexene in the presence of a
solid-acid catalyst such as molecular sieves in the MCM-22 family
according to the following Reaction-2:
##STR00002##
[0049] Side reactions may occur in Reaction-1 or Reaction-2 to
produce some polyalkylated benzenes, such as dicyclohexylbenzenes
(DiCHB), tricyclohexylbenzenes (TriCHB), methylcyclopentylbenzene,
unreacted benzene, cyclohexane, bicyclohexane, biphenyl, and other
contaminants Thus, typically, after the reaction, the
hydroalkylation reaction product mixture is separated by
distillation to obtain a C6 fraction containing benzene,
cyclohexane, a C12 fraction containing cyclohexylbenzene and
methylcyclopentylbenzene, and a heavies fraction containing, e.g.,
C18s such as DiCHBs and C24s such as TriCHBs. The unreacted benzene
may be recovered by distillation and recycled to the
hydroalkylation or alkylation reactor. The cyclohexane may be sent
to a dehydrogenation reactor, with or without some of the residual
benzene, and with or without co-fed hydrogen, where it is converted
to benzene and hydrogen, which can be recycled to the
hydroalkylation/alkylation step. Depending on the quantity of the
heavies fraction, it may be desirable to either (a) transalkylate
the C18s such as DiCHB and C24s such as TriCHB with additional
benzene or (b) dealkylate the C18s and C24s to maximize the
production of the desired monoalkylated species.
[0050] Details of feed materials, catalyst used, reaction
conditions, and reaction product properties of benzene
hydroalkylation, and transalkylation and dealkylation can be found
in, e.g., the following copending, co-assigned patent applications:
U.S. Provisional Patent Application Ser. No. 61/972,877, entitled
"Process for Making Cyclohexylbenzene and/or Phenol and/or
Cyclohexanone;" and filed on Mar. 31, 2014; U.S. Provisional Patent
Application Ser. No. 62/037,794, entitled "Process and System for
Making Cyclohexanone," and filed on Aug. 15, 2014; U.S. Provisional
Patent Application Ser. No. 62/037,801, entitled "Process and
System for Making Cyclohexanone," and filed on Aug. 15, 2014; U.S.
Provisional Patent Application Ser. No. 62/037,814, entitled
"Process and System for Making Cyclohexanone," and filed on Aug.
15, 2014; U.S. Provisional Patent Application Ser. No. 62/037,824,
entitled "Process and System for Making Cyclohexanone," and filed
on Aug. 15, 2014; U.S. Provisional Patent Application Ser. No.
62/057,919, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014; U.S. Provisional Patent Application Ser. No.
62/057,947, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014; and U.S. Provisional Patent Application Ser. No.
62/057,980, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014, the contents of all of which are incorporated
herein by reference in their entirety.
Oxidation of Cyclohexylbenzene
[0051] In the oxidation step, at least a portion of the
cyclohexylbenzene contained in the oxidation feed is converted to
cyclohexyl-1-phenyl-1-hydroperoxide, the desired hydroperoxide,
according to the following Reaction-3:
##STR00003##
[0052] The cyclohexylbenzene freshly produced and/or recycled may
be purified before being fed to the oxidation step to remove at
least a portion of, among others, methylcyclopentylbenzene,
olefins, phenol, acid, and the like. Such purification may include,
e.g., distillation, hydrogenation, caustic wash, and the like.
[0053] In exemplary processes, the oxidation step may be
accomplished by contacting an oxygen-containing gas, such as air
and various derivatives of air, with the feed comprising
cyclohexylbenzene. For example, a stream of pure O.sub.2, O.sub.2
diluted by inert gas such as N.sub.2, pure air, or other
O.sub.2-containing mixtures can be pumped through the
cyclohexylbenzene-containing feed in an oxidation reactor to effect
the oxidation.
[0054] The oxidation may be conducted in the absence or presence of
a catalyst, such as a cyclic imide type catalyst (e.g.,
N-hydroxyphthalimide).
[0055] Details of the feed material, reaction conditions, reactors
used, catalyst used, product mixture composition and treatment, and
the like, of the oxidation step can be found in, e.g., the
following copending, co-assigned patent applications: U.S.
Provisional Patent Application Ser. No. 61/972,877, entitled
"Process for Making Cyclohexylbenzene and/or Phenol and/or
Cyclohexanone;" and filed on Mar. 31, 2014; U.S. Provisional Patent
Application Ser. No. 62/037,794, entitled "Process and System for
Making Cyclohexanone," and filed on Aug. 15, 2014; U.S. Provisional
Patent Application Ser. No. 62/037,801, entitled "Process and
System for Making Cyclohexanone," and filed on Aug. 15, 2014; U.S.
Provisional Patent Application Ser. No. 62/037,814, entitled
"Process and System for Making Cyclohexanone," and filed on Aug.
15, 2014; U.S. Provisional Patent Application Ser. No. 62/037,824,
entitled "Process and System for Making Cyclohexanone," and filed
on Aug. 15, 2014; U.S. Provisional Patent Application Ser. No.
62/057,919, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014; U.S. Provisional Patent Application Ser. No.
62/057,947, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014; and U.S. Provisional Patent Application Ser. No.
62/057,980, entitled "Process for Making Cyclohexanone," and filed
on Sep. 30, 2014, the contents of all of which are incorporated
herein by reference in their entirety.
Cleavage Reaction
[0056] In the cleavage reaction, at least a portion of the
cyclohexyl-1-phenyl-1-hydroperoxide decomposes in the presence of
an acid catalyst in high selectivity to cyclohexanone and phenol
according to the following desired Reaction-4:
##STR00004##
[0057] The cleavage product mixture may comprise the acid catalyst,
phenol, cyclohexanone, cyclohexylbenzene, and contaminants.
[0058] The acid catalyst can be at least partially soluble in the
cleavage reaction mixture, is stable at a temperature of at least
185.degree. C. and has a lower volatility (higher normal boiling
point) than cyclohexylbenzene.
[0059] Feed composition, reaction conditions, catalyst used,
product mixture composition and treatment thereof, and the like, of
this cleavage step can be found in, e.g., the following copending,
co-assigned patent applications: U.S. Provisional Patent
Application Ser. No. 61/972,877, entitled "Process for Making
Cyclohexylbenzene and/or Phenol and/or Cyclohexanone;" and filed on
Mar. 31, 2014; U.S. Provisional Patent Application Ser. No.
62/037,794, entitled "Process and System for Making Cyclohexanone,"
and filed on Aug. 15, 2014; U.S. Provisional Patent Application
Ser. No. 62/037,801, entitled "Process and System for Making
Cyclohexanone," and filed on Aug. 15, 2014; U.S. Provisional Patent
Application Ser. No. 62/037,814, entitled "Process and System for
Making Cyclohexanone," and filed on Aug. 15, 2014; U.S. Provisional
Patent Application Ser. No. 62/037,824, entitled "Process and
System for Making Cyclohexanone," and filed on Aug. 15, 2014; U.S.
Provisional Patent Application Ser. No. 62/057,919, entitled
"Process for Making Cyclohexanone," and filed on Sep. 30, 2014;
U.S. Provisional Patent Application Ser. No. 62/057,947, entitled
"Process for Making Cyclohexanone," and filed on Sep. 30, 2014; and
U.S. Provisional Patent Application Ser. No. 62/057,980, entitled
"Process for Making Cyclohexanone," and filed on Sep. 30, 2014, the
contents of all of which are incorporated herein by reference in
their entirety.
Separation and Purification
[0060] A portion of the neutralized cleavage reaction product can
then be separated by methods such as distillation. In one example,
in a first distillation column after the cleavage reactor, a
heavies fraction comprising heavies (such as amine sulfuric acid
complex, which can be regarded as an amine sulfate salt, if an
organic amine is used to neutralize at least a portion of the
sulfuric acid present in the cleavage reaction product before it is
fed into the first distillation column) is obtained at the bottom
of the column, a side fraction comprising cyclohexylbenzene is
obtained in the middle section, and an upper fraction comprising
cyclohexanone, phenol, methylcyclopentanone, and water is
obtained.
[0061] The separated cyclohexylbenzene fraction can then be treated
and/or purified before being delivered to the oxidation step. Since
the cyclohexylbenzene separated from the cleavage product mixture
may contain phenol and/or olefins such as cyclohexenylbenzenes, the
material may be subjected to treatment with an aqueous composition
comprising a base and/or a hydrogenation step as disclosed in, for
example, WO 2011/100013A1, the entire contents of which are
incorporated herein by reference.
[0062] In one example, the fraction comprising phenol,
cyclohexanone, and water can be further separated by simple
distillation to obtain an upper fraction comprising primarily
cyclohexanone and methylcyclopentanone and a lower fraction
comprising primarily phenol, and some cyclohexanone. Cyclohexanone
cannot be completely separated from phenol without using an
extractive solvent due to an azeotrope formed between these two.
Thus, the upper fraction can be further distillated in a separate
column to obtain a pure cyclohexanone product in the vicinity of
the bottom and an impurity fraction in the vicinity of the top
comprising primarily methylcyclopentanone, which can be further
purified, if needed, and then used as a useful industrial material.
The lower fraction can be further separated by a step of extractive
distillation using an extractive solvent (e.g., sulfolane, and
glycols such as ethylene glycol, propylene glycol, diethylene
glycol, triethylene glycol, and the like) described in, e.g.,
co-assigned, co-pending patent applications WO 2013/165656A1 and WO
2013/165659, the contents of which are incorporated herein by
reference in their entirety. An upper fraction comprising
cyclohexanone and a lower fraction comprising phenol and the
extractive solvent can be obtained. In a subsequent distillation
column, the lower fraction can then be separated to obtain an upper
fraction comprising a phenol product and a lower fraction
comprising the extractive solvent.
[0063] Where an acid, such as sulfuric acid, is used as the
catalyst in the cleavage step, and a liquid amine is used as the
neutralizing agent to neutralize at least a portion of the acid
before the cleavage product mixture is fed into the first
distillation column, the acid will react with the amine to form a
complex that is fed into the first distillation column as well. It
had been hoped that given the high boiling point of the complex, it
would stay in the bottom fraction of the first distillation column,
and therefore all sulfur would be removed completely from the
bottoms of the first distillation column. However, in a very
surprising manner, it has been found that sulfur was present in the
fraction comprising cyclohexanone and phenol exiting the first
distillation column.
[0064] Without intending to be bound by a particular theory, it is
believed that the complex between the acid catalyst and the organic
amine, if present in the feed to the first distillation column, can
decompose at least partially in the first distillation column, due
to the high operating temperature therein (i.e., the highest
temperature the liquid media is exposed to in the first
distillation column, typically in the vicinity of the bottom of the
column and/or in the reboiler) of at least 120.degree. C. (even
130.degree. C., 140.degree. C., 150.degree. C., 160.degree. C.,
170.degree. C., 180.degree. C., 190.degree. C., 200.degree. C.,
210.degree. C., 220.degree. C., 230.degree. C., 240.degree. C., or
even 250.degree. C.) is used, necessitated by the separation of
cyclohexylbenzene present therein at high concentrations (e.g., at
least 5 wt %, or 10 wt %, or 15 wt %, or 20 wt %, or 25 wt %, or 30
wt %, or 35 wt %, or 40 wt %, or 45 wt %, or even 50 wt %, based on
the total weight of the cleavage product mixture), which has a very
high normal boiling temperature (240.degree. C., compared to the
normal boiling temperature of cumene of 152.degree. C.). The
decomposition of the complex likely produces, among others,
SO.sub.3, which can easily travel upwards along the first
distillation column to upper locations, where it can recombine at
least partially with water to form H.sub.2SO.sub.4. This operation
temperature can be significantly higher than the distillation
temperature the mixture of cumene, phenol, and acetone is exposed
to in the first distillation column in the cumene process for
making phenol and acetone.
[0065] Thus, the presence of acid, especially strong acid such as
SO.sub.3, R--HSO.sub.4, and/or sulfuric acid in the first
distillation column, can catalyze many undesirable side reactions
between and among the many components present in the distillation
mixture, leading to the formation of byproducts (including
S-containing components) and/or premature malfunction of the
distillation column. Furthermore, at high operation temperature,
prolonged exposure to the acid can cause significant corrosion to
the column equipment. The acid species can also make their way into
the various fractions drawn from the different locations of the
first distillation column, causing different problems in subsequent
steps where the fractions are further processed. If the acid
species and/or S-containing component enter into a down-stream
hydrogenation reactor (described below) where phenol is
hydrogenated to make additional cyclohexanone, the hydrogenation
catalyst can be easily deactivated.
[0066] Therefore, treating the cleavage product mixture before it
enters into the first distillation column using a solid-phase basic
material according to the present invention is highly advantageous
and desirable. Doing so would reduce or eliminate the presence of
acid species in media inside the first distillation column, avoid
undesirable side reactions and byproducts formed as a result of
contact with the acid species, reduce corrosion of the first
distillation column caused by the acid species and the associated
repair and premature replacement, and prevent undesirable side
reactions and byproduct formation in subsequent steps.
[0067] Such basic materials useful for treatment according to such
embodiments, advantageously in solid-phase under the operation
conditions, can be selected from (i) oxides of alkali metals,
alkaline earth metals, and zinc; (ii) hydroxides of alkali metals,
alkaline earth metals, and zinc; (iii) carbonates of alkali metals,
alkaline earth metals, and zinc; (iv) bicarbonates of alkali
metals, alkaline earth metals, and zinc; (v) complexes of two or
more of (i), (ii), (iii), and (iv); (vi) solid amines; (vii)
ion-exchange resins; and (viii) mixtures and combinations of two or
more of (i), (ii), (iii), (iv), (v), (vi), and (vii). Oxides,
hydroxides, carbonates and bicarbonates of alkali and alkaline
earth metals and zinc can react with acid to form salts thereof,
which preferably, are also in solid-phase under the operation
conditions. Preferably, an ion exchange resin is used. Such ion
exchange resin preferably comprise groups on the surface thereof
capable of adsorbing and/or binding with protons, SO.sub.3,
HSO.sub.4.sup.-, H.sub.2SO.sub.4, complexes of sulfuric acid, and
the like. The ion exchange resin can comprise a strong and/or a
weak base resin. Weak base resins primarily function as acid
adsorbers. These resins are capable of sorbing strong acids with a
high capacity. Strong base anion resins can comprise quarternized
amine-based products capable of sorbing both strong and weak acids.
Commercial examples of basic ion exchange resins useful in the
present invention include but are not limited to: Amberlyst.RTM.
A21 and Amberlyst.RTM. A26 basic ion exchange resins available from
Dow Chemical Company. Amberlyst.RTM. A26 is an example of a strong
base, type 1, anionic, macroreticular polymeric resin. According to
Dow Chemical Company, the resin is based on crosslinked styrene
divinylbenzene copolymer, containing quaternary ammonium groups.
A26 is generally considered to be a stronger base resin than
A21.
[0068] After treatment using a solid-phase base and/or ion exchange
resin, both total acid concentration and acid precursor
concentration in the feed supplied to the first distillation column
can be exceedingly low (e.g., 50 ppm or less, such as less than or
equal to 20, 15, 10, 5, or 1 ppm). Accordingly, the first
distillation column can be operated at a high operation
temperature, such as temperatures higher than the disassociation
temperatures of complex materials formed between the acid catalyst
used in the cleavage step, such as sulfuric acid, and the following
organic amines: (i) pentane-1,5-diamine; (ii)
1-methylhexane-1,5-diamine; (iii) hexane-1,6-diamine; (iv)
2-methylpentane-1,5-diamine; (v) ethylene diamine; (vi) propylene
diamine; (vii) diethylene triamine; and (viii) triethylene
tetramine, without the concern of issues associated with acid
produced from thermal dissociation thereof under such high
operation temperature.
Separation and Hydrogenation
[0069] At least a portion, preferably the entirety, of the
neutralized cleavage effluent (cleavage reaction product), may be
separated and a phenol-containing fraction thereof can be
hydrogenated to convert a portion of the phenol to cyclohexanone in
accordance with the present invention.
[0070] It has been found that hydrogenation catalyst used for
hydrogenating phenol to make additional quantities of phenol is
highly susceptible to poisoning by S-containing components and/or
acids in the feed to the hydrogenation reactor, as well as to other
catalyst poison components that may be present in the neutralized
cleavage effluent. As such, it is highly desirable that acids
and/or S-containing components, as well as other catalyst poison
components, are removed from the stream prior to being fed into the
hydrogenation reactor.
[0071] Examples of the separation and hydrogenation process and/or
system are illustrated in the attached drawings and described in
detail below. It should be understood that process and/or systems
shown in the schematic, not-to-scale drawings are only for the
purpose of illustrating the general material and/or heat flows and
general operating principles. To simplify illustration and
description, some routine components, such as pumps, valves,
reboilers, pressure regulators, heat exchangers, recycling loops,
condensers, separation drums, sensors, rectifiers, fillers,
distributors, stirrers, motors, and the like, are not shown in the
drawings or described herein. One having ordinary skill in the art,
in light of the teachings herein, can add those components where
appropriate.
[0072] FIGS. 1, 2, 3, 4, 5, 6, and 9 illustrate processes and
systems that do not include an anterior or posterior sorbent bed
before or after the first distillation column for separating
cyclohexanone from phenol for the purpose of poison removal from
the hydrogenation feed. Nonetheless, because these drawings show
systems and processes on which the present invention is based, they
are included and described herein.
[0073] FIG. 1 is a schematic diagram showing a process/system 101
for making cyclohexanone from a mixture comprising phenol,
cyclohexanone and cyclohexylbenzene including a first distillation
column T1 (i.e., the first distillation column), a hydrogenation
reactor R1, and a cyclohexanone purification column T2 (i.e., the
second distillation column). Feed 103 from storage S1, comprising
phenol, cyclohexanone, and cyclohexylbenzene, is fed into the first
distillation column T1.
[0074] Feed 103 can be produced by any method. A preferred method
is by cleaving a cyclohexylbenzene hydroperoxide in the presence of
an acid catalyst such as sulfuric acid and cyclohexylbenzene as
described above. Feed 103 may further comprise impurities other
than cyclohexylbenzene such as: hydrogenation catalyst poisons;
light components (defined above) such as water,
methylcyclopentanone, pentanal, hexanal, benzoic acid, and the
like, and heavy components such as methylcyclopentylbenzene,
bicyclohexane, sulfate of an organic amine (such as
1,6-hexamethylenediame, 2-methyl-1,5-pentamethylenediamine,
ethylenediamine, propylenediamine, diethylenetriamine, and the
like) produced by injecting the amine into the cleavage mixture to
neutralize the liquid acid catalyst used. Feed 103 may further
comprise olefins heavier than cyclohexanone such as
phenylcyclohexene isomers, hydroxylcyclohexanone, cyclohexenone,
and the like. The cyclohexylbenzene hydroperoxide may be produced
by aerobic oxidation of cyclohexylbenzene in the presence of a
catalyst such as NHPI as described above. The cyclohexylbenzene may
be produced by hydroalkylation of benzene in the presence of a
hydrogenation/alkylation bi-functional catalyst as described
above.
[0075] Thus, feed 103 (the first mixture) may comprise, based on
the total weight thereof: [0076] 10 wt % to 90 wt % (such as about
20 wt % to about 30 wt %, or 20 wt % to about 40 wt %)
cyclohexanone; [0077] 10 wt % to 90 wt % (such as about 20 wt % to
about 30 wt %, or 20 wt % to about 40 wt %) phenol (further, the
ratio of wt % cyclohexanone to wt % phenol in the feed is
preferably from 0.5 to 1.5); [0078] 0.001 wt % to 90 wt %
(preferably 20 wt % to 70 wt %, such as 30 wt % to 60 wt %)
cyclohexylbenzene; [0079] 0.001 wt % to 1 wt % bicyclohexane; and
[0080] light components (e.g., benzoic acid, and other carboxylic
acids comprising 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms),
S-containing compounds, and N-containing compounds each at a
concentration ranging from about 0.1 ppm to 10,000 ppm, preferably
1 to 5000 ppm.
[0081] From the first distillation column T1, a first upper
effluent 105 comprising a portion of the cyclohexanone and a
portion of light components such as water, methylcyclopentanone,
and the like, is produced in the vicinity of the top of the column
T1. Effluent 105 may comprise, based on the total weight thereof:
[0082] 60 wt % to 99.9 wt %, preferably 75 wt % to 95 wt % or 99.9
wt %, cyclohexanone; [0083] 0 wt % to 1 wt % of each of phenol,
cyclohexylbenzene, and bicyclohexane; [0084] 0.001 wt % to 10 wt %
(preferably 0.1 to 5.0 wt %) cyclohexanol; and [0085] light
components at a total concentration of 0.001 wt % to 5.0 wt %
(preferably 0.001 wt % to 1.0 wt %).
[0086] The first upper effluent 105 is then sent to a cyclohexanone
purification column T2, from which a third upper effluent 121
comprising light components such as water, methylcyclopentanone,
and the like, is produced at a location in the vicinity of the top
of column T2 and then delivered to storage S5. A second upper
effluent 123 comprising essentially pure cyclohexanone is produced
and sent to storage S7. In the vicinity of the bottom of column T2,
a second lower effluent 125 is produced and delivered to storage
S9. The second lower effluent can be, e.g., a KA oil comprising
both cyclohexanone and cyclohexanol. Thus, the second upper
effluent 123 may comprise, based on the total weight thereof, 95 to
99.9999 wt % (such as 95 wt % to 99.9 wt %) cyclohexanone. The
second lower effluent 125 may comprise, based on the total weight
thereof: 10 wt % to 80 wt % cyclohexanol; and 10 wt % to 80 wt %
(such as 10 wt % to 40 wt %) cyclohexanone.
[0087] The first middle effluent 107 produced from the first
distillation column T1 comprises phenol at a concentration higher
than in feed 103 and higher than in the first upper effluent 105,
cyclohexanone at a concentration lower than in both feed 103 and
the first upper effluent 105, cyclohexylbenzene at a concentration
desirably lower than in feed 103 and higher than in the first upper
effluent 105, and one or more of other impurities such as
bicyclohexane and cyclohexenone. Thus, effluent 107 may comprise,
based on total weight thereof: [0088] 1 wt % to 50 wt % (such as 5
wt % to 30 wt %) cyclohexanone; [0089] 10 wt % to 80 wt % (such as
20 wt % to 80 wt %) phenol, further wherein the weight ratio of
phenol to cyclohexanone is preferably within the range from 1.0 to
3.0, more preferably from 2.0 to 3.0; [0090] 0.001 wt % to 30 wt %
(such as 0.001 wt % to 10 wt %) cyclohexylbenzene; [0091] 0.001 wt
% to 30 wt % (such as 0.001 wt % to 25 wt %) bicyclohexane; [0092]
0.01 wt % to 30 wt % (such as 0.01 wt % to 5 wt %) cyclohexanol;
and [0093] light components (e.g., benzoic acid, and other organic
acid comprising 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms),
S-containing compounds, and N-containing compounds each at a
concentration of 0 wppm to 5000 wppm, preferably 0 wppm to 1000
wppm, such as 1 ppm to 1000 ppm.
[0094] Preferably, effluent 107 is essentially free of catalyst
poison components, including S-containing components, that may
poison the hydrogenation catalyst used in the hydrogenation
reactor(s) R1. However, depending on the quality of feed 103,
effluent 107 may comprise catalyst poison components (such as
S-containing components) at concentrations capable of leading to
poisoning of the hydrogenation catalyst, as discussed above. In
such case, embodiments according to the processes and systems
illustrated in FIGS. 7 and 8 and described in detail below may be
advantageously used to reduce the catalyst poison components
(including S-containing components) from effluent 107 before it is
fed into the hydrogenation reactor as the whole or a portion of the
hydrogenation feed.
[0095] Otherwise, effluent 107, if containing catalyst poison
components at acceptably low concentration(s), can be directly
delivered to a hydrogenation reactor R1, where the effluent 107 is
mixed with a hydrogen gas feed 112 comprising fresh make-up
hydrogen stream 111 from storage S3 and recycle hydrogen 117. The
phenol contained in feed 107 and hydrogen reacts with each other in
the presence of a catalyst bed 113 inside reactor R1 to produce
cyclohexanone. Some of the cyclohexanone inside the reactor R1
reacts with hydrogen in the presence of the catalyst bed 113 as
well to produce cyclohexanol. In the exemplary process shown in
FIG. 1, surplus hydrogen is fed into reactor R1. It is contemplated
that a second phenol-containing stream (not shown), separate from
and independent of effluent 107, may be fed into the hydrogenation
reactor R1. Such additional feed can advantageously contain 50 wt %
to 100 wt % phenol. Preferably, the second phenol-containing stream
comprises substantially pure phenol produced by any process, such
as the conventional cumene process, coal-based processes, and the
like.
[0096] The total hydrogenation feed, including stream 107 and
optional additional streams, delivered to the hydrogenation reactor
R1, if blended together before being fed into R1, may have an
overall composition comprising, based on the total weight of the
hydrogen feed stream 107 and optional additional streams: [0097]
0.1 to 50 wt % cyclohexanone (such as 0.1 to 50 wt %, more
particularly 10 wt % to 50 wt %, even more particularly 20 wt % to
45 wt %); [0098] 10 to 99 wt % phenol (such as 30 to 95, or 40 to
85 wt %); and [0099] 0.001 to 30 wt % of each of cyclohexylbenzene
and bicyclohexane (such as 0.1 wt % to 25 wt %, preferably 1 wt %
to 20 wt % each).
[0100] In the hydrogenation reaction zone, the following reactions
can take place, resulting in an increase of concentrations of
cyclohexanone, cyclohexanol, and bicyclohexane, and a decrease of
concentrations of phenol, cyclohexanone, and cyclohexylbenzene:
##STR00005##
[0101] Cyclohexanone may hydrogenate to make cyclohexanol in the
hydrogenation reactor R1. Because the net effect of the reaction is
an overall increase of cyclohexanone concentration, this reaction
is not included in the above paragraph. Nonetheless, cyclohexanone
can engage in competition against phenol for hydrogen, which should
be reduced or inhibited.
[0102] The total amount of hydrogen, including fresh, make-up
hydrogen and recycled hydrogen, fed into the reactor R1, and the
total amount of phenol fed into the hydrogenation reaction zone
desirably exhibit a hydrogen to phenol molar ratio falling within
the range of 1:1 to 10:1, preferably within the range of 1:1 to
5:1. While a higher R(H2/phol) ratio can result in higher overall
conversion of phenol, it tends to result in higher conversion of
cyclohexanone, higher selectivity of phenol to cyclohexanol, and
higher conversion of cyclohexylbenzene, as well. Therefore, it is
generally desirable that in the hydrogenation reactor R1, the
reaction conditions, including but not limited to temperature,
pressure, and R(H2/phol) ratio, and catalysts, are chosen such that
the overall conversion of phenol is not too high.
[0103] The hydrogenation reactions take place in the presence of a
hydrogenation catalyst. The hydrogenation catalyst may comprise a
hydrogenation metal performing a hydrogenation function supported
on a support material. The hydrogenation metal can be, e.g., Fe,
Co, Ni, Ru, Rh, Pd, Ag, Re, Os, Ir, and Pt, and mixtures and
combinations of one or more thereof. The support material can be
advantageously an inorganic material, such as oxides, glasses,
ceramics, molecular sieves, and the like. For example, the support
material can be activated carbon, Al.sub.2O.sub.3, Ga.sub.2O.sub.3,
SiO.sub.2, GeO.sub.2, SnO, SnO.sub.2, TiO.sub.2, ZrO.sub.2,
Sc.sub.2O.sub.3, Y.sub.2O.sub.3, alkali metal oxides, alkaline
earth metal oxides, and mixtures, combinations, complexes, and
compounds thereof. The concentration of the hydrogenation metal can
be, e.g., in a range from Cm1 wt % to Cm2 wt %, based on the total
weight of the catalyst, where Cm1 and Cm2 can be, independently:
0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5,
4.0, 4.5, 5.0, as long as Cm1<Cm2.
[0104] Without intending to be bound by any particular theory, it
is believed that the above hydrogenation reactions occur quickly in
the presence of the hydrogenation metal. Therefore, it is highly
desirable that the hydrogenation metal is preferentially
distributed in the outer rim of the catalyst particles, i.e., the
concentration of the hydrogenation metal in the catalyst particle
surface layer is higher than in the core thereof. Such rimmed
catalyst can reduce the overall hydrogenation metal loading,
reducing cost thereof, especially if the hydrogenation metal
comprises a precious metal such as Pt, Pd, Ir, Rh, and the like.
The low concentration of hydrogenation metal in the core of the
catalyst particle also leads to a lower chance of hydrogenation of
cyclohexanone, which may diffuse from the surface to the core of
the catalyst particles, resulting in higher selectivity of
cyclohexanone in the overall process.
[0105] Certain light components, such as organic acids (e.g.,
formic acid, acetic acid, propanoic acid, linear, linear branched
and cyclic carboxylic acids comprising 5, 6, 7, or 8 carbon atoms
such as benzoic acid), N-containing compounds (e.g., amines,
imides, amides, NO.sub.2-substituted organic compounds), and
S-containing compounds (e.g., sulfides, sulfites, sulfates,
sulfones, SO.sub.3, SO.sub.2), if contained in the reaction mixture
in the hydrogenation reactor and allowed to contact the
hydrogenation metal under the hydrogenation reaction conditions,
poisoning of the hydrogenation catalyst can occur, leading to
reduction of performance or premature failure of the catalyst. To
avoid catalyst poisoning, it is highly desirable that the
hydrogenation feed comprises such catalyst poison components at low
concentrations described above.
[0106] It is believed that the catalyst surface can have different
degrees of adsorption affinity to the different components in the
reaction media such as phenol, cyclohexanone, cyclohexanol,
cyclohexenone, cyclohexylbenzene, and bicyclohexane. It is highly
desired that the catalyst surface has higher adsorption affinity to
phenol than to cyclohexanone and cyclohexylbenzene. Such higher
phenol adsorption affinity will give phenol competitive advantages
in the reactions, resulting in higher selectivity to cyclohexanone,
lower selectivity of cyclohexanol, and lower conversion of
cyclohexylbenzene, which are all desired in a process designed for
making cyclohexanone. In addition, in order to favor the conversion
of phenol to cyclohexanone over the conversion of cyclohexylbenzene
to bicyclohexane and the conversion of cyclohexanone to
cyclohexanol, it is highly desired that the phenol concentration in
the reaction medium in the hydrogenation reactor R1 is relatively
high, so that phenol molecules occupy most of the active catalyst
surface area. Therefore, it is desired that the overall conversion
of phenol in the reactor R1 is relatively low.
[0107] As such, it is desired that in the hydrogenation reactor R1,
any one or more of the following conditions is met: [0108] (i)
30%.ltoreq.conversion of phenol.ltoreq.95%; [0109] (ii)
0.1%.ltoreq.conversion of cyclohexylbenzene.ltoreq.20%; [0110]
(iii) 80%.ltoreq.selectivity of phenol to cyclohexanone
conversion.ltoreq.99.9%; and [0111] (iv) 0.1%.ltoreq.selectivity of
phenol to cyclohexanol conversion.ltoreq.20%.
[0112] The feed(s) to the hydrogenation reactor R1 may further
comprise 0.01 wt % to 5 wt % cyclohexenone. It is highly desired
that the conversion of cyclohexenone in the reactor R1 is within
the range from 85 to 100%. Thus, a great majority of the
cyclohexenone contained in the feed(s) is converted into
cyclohexanone in the hydrogenation reactor R1.
[0113] At the bottom of reactor R1, a hydrogenation reaction
product stream 115 comprising phenol at a concentration lower than
in stream 107, cyclohexanone at a concentration higher than in
stream 107, cyclohexylbenzene, bicyclohexane, and surplus hydrogen
is taken. Stream 115 may comprise, based on the total weight
thereof: [0114] 20 wt % to 90 wt % (such as 30 wt % or 50 wt % to
90 wt %) Cyclohexanone; [0115] 1 wt % to 50 wt % (such as 1 wt % to
15 or 20 wt %) Phenol; [0116] 0.001 wt % to 30 wt % (such as 0.001
wt % to 15 wt % or 20 wt %) cyclohexylbenzene; [0117] 0.001 wt % to
30 wt % (such as 0.001 wt % to 10 wt % or 15 wt %) bicyclohexane;
and [0118] 0.01 wt % to 10 wt % (such as 0.01 wt % to 5 wt %)
cyclohexanol.
[0119] Stream 115 is then delivered to a separation drum D1, where
a vapor phase comprising a majority of the surplus hydrogen and a
liquid phase is obtained. The vapor phase can be recycled as stream
117 to reactor R1 as part of the hydrogen supply, and the liquid
phase 119 is recycled to the first distillation column T1 at one or
more side locations on column T1, at least one of which is above
the location where the first middle effluent 107 is taken, but
below the location where the first upper effluent 105 is taken.
[0120] The first bottom effluent 109 obtained from the first
distillation column T1 comprises primarily heavy components such as
cyclohexylbenzene, bicyclohexane, amine salts mentioned above,
C18+, C12 oxygenates, and C18+ oxygenates. This fraction is
delivered to a heavies distillation column T3 (the third
distillation column), from which a fourth upper effluent 127
desirably comprising cyclohexylbenzene at a concentration higher
than C31 80% and a lower effluent 129 are produced. Effluent 127
may be delivered to storage S11 and effluent 129 to storage S13.
Effluent 127 may further comprise olefins, primarily
phenylcyclohexene isomers, at a non-negligible amount. It may be
desirable to subject effluent 127 to hydrogenation to reduce olefin
concentrations, and subsequently recycle the hydrogenated effluent
127 to an earlier step such as cyclohexylbenzene oxidation to
convert at least a portion of it to cyclohexylbenzene
hydroperoxide, such that the overall yield of the process is
improved.
[0121] FIG. 2 is a schematic diagram showing a portion of a
process/system similar to the process/system shown in FIG. 1, but
comprising modified fluid communications between and/or within the
first distillation column T1 and the hydrogenation reactor R1. In
this figure, the hydrogenation reaction product 115 comprises
residual hydrogen, as in the example shown in FIG. 1. Effluent 115
is first delivered into separation drum D1, where a hydrogen-rich
vapor stream 117a is obtained, compressed by a compressor 118, and
then delivered to reactor R1 as a stream 117b together with fresh,
make-up hydrogen stream 111 into reactor R1. A liquid stream 119 is
obtained from separation drum D1, then divided into multiple
streams (two recycle streams 119a and 119b shown in FIG. 2),
recycled to two different locations on the side of column T1, one
below the location where the first middle effluent 107 is taken
(shown at approximately the same level as feed 103), and the other
above the location where the first middle effluent 107 is drawn.
This modified recycle fluid communication between the hydrogenation
reactor R1 and the first distillation column T1 compared to FIG. 1
has surprising advantages. It was found that where the recycle
liquid stream 119 is fed to one location only, such as at a
location above the first middle effluent 107, bicyclohexane is
continuously produced in reactor R1 from the cyclohexylbenzene in
stream 107, and then steadily accumulates in column T1 to such high
concentration that a separate phase can form, interfering with
effective product separation in column T1. On the other hand, where
the recycle stream 119 is recycled back to column T1 at multiple
locations on T1 (as shown in FIG. 2), the probability of forming a
separate bicyclohexane phase inside T1 is drastically reduced or
eliminated. Such a configuration, then, may substantially reduce
the presence of impurities such as bicyclohexane in the final
cyclohexanone product.
[0122] FIG. 3 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1 and 2 comprising
modified fluid communications and/or heat transfer arrangement
between and/or within the first distillation column T1 and the
cyclohexanone purification column T2. In this figure, the
hydrogenation reactor R1 and its peripheral equipment are not
shown. In this figure, the first middle effluent 107 drawn from
column T1 is divided into multiple streams (two streams 107a and
107b shown), one of which (107a) is delivered to the hydrogenation
reactor R1 (not shown) as hydrogenation feed, and the other (107b)
to a heat exchanger 131 in fluid and thermal communication with the
cyclohexanone purification column T2. In this figure, the bottom
stream 125 (e.g., comprising a mixture of cyclohexanone and
cyclohexanol) from column T2 is divided into three streams: stream
135 which passes through heat exchanger 131 and is heated by stream
107b; stream 139 which is heated by a heat exchanger 141 and then
recycled to column T2; and stream 145, which is delivered to
storage S9 via pump 147. Stream 107b becomes a cooler stream 133
after passing through heat exchanger 131, and is then subsequently
recycled to first distillation column T1 at one or more locations,
at least one of which is located above the location where the first
middle effluent 107 is drawn. A heat management scheme as
illustrated in FIG. 3 can significantly improve the energy
efficiency of the overall process and system.
[0123] FIG. 4 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1-3, but comprising
a tubular heat exchanger-type hydrogenation reactor. This figure
illustrates an example where the hydrogenation reactor R1 operates
under hydrogenation conditions such that a majority of the phenol
and/or cyclohexylbenzene present in the reaction media inside the
reactor R1 are in vapor phase. In this figure, the first middle
effluent 107 taken from the first distillation column T1 is first
combined with hydrogen feeds (including fresh make-up hydrogen
stream 111 and recycle hydrogen stream 117b), heated by a heat
exchanger 153 and then delivered to a tubular heat-exchanger type
hydrogenation reaction R1 having hydrogenation catalyst installed
inside the tubes 157. A stream of cooling media 159 such as cold
water supplied from storage S11 passes through the shell of the
exchanger/reactor R1 and exits the reactor R1 as a warm stream 161
and is then delivered to storage S13, thereby a significant amount
of heat released from phenol hydrogenation reaction is carried
away, maintaining the temperature inside the reactor R1 in a range
from 140.degree. C. to 300.degree. C. (preferably about 220.degree.
C. to about 260.degree. C., such as about 240.degree. C.), and an
absolute pressure inside the reactor R1 in a range from 100 kPa to
400 kPa (preferably about 180 kPa to about 220 kPa, such as about
200 kPa). Alternatively, the cooling medium may comprise at least a
portion of the hydrogenation feed in liquid phase, such that at
least a portion of the feed is vaporized, and at least a portion of
the vapor feed is then fed to the hydrogenation reactor R1.
[0124] Because heat transfer of a vapor phase is not as efficient
as a liquid phase, and the phenol hydrogenation reaction is highly
exothermic, it is highly desired that heat transfer is carefully
managed in such vapor phase hydrogenation reactor. Other types of
reactors suitable for a liquid phase reaction can be used as well.
For example, fixed-bed reactors configured to have intercooling
capability and/or quenching options, so that the heat generated in
the reaction can be taken away sufficiently quickly to maintain the
reaction media in a desirable temperature range.
[0125] FIG. 5 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1-4, but comprising
three fixed bed hydrogenation reactors R3, R5, and R7 connected in
series. This figure illustrates an example where the hydrogenation
reactors operate under hydrogenation conditions such that a
majority of the phenol and/or cyclohexylbenzene present in the
reaction media inside the reactors R3, R5, and R7 are in liquid
phase. In this figure, the first middle effluent 107 taken from the
first distillation column T1 is first combined with hydrogen feeds
(including fresh make-up hydrogen stream 111 and recycle hydrogen
stream 117b) to form a feed stream 151, then heated by a heat
exchanger 153, and then delivered as stream 155 to a first
hydrogenation reactor R3 having a catalyst bed 167 inside. A
portion of the phenol is converted to cyclohexanone in reactor R3,
releasing a moderate amount of heat raising the temperature of the
reaction media. Effluent 169 exiting reactor R3 is then cooled down
by heat exchanger 171, and then delivered into a second fixed bed
reactor R5 having a catalyst bed 175 inside. A portion of the
phenol contained in the reaction media is converted to
cyclohexanone in reactor R5, releasing a moderate amount of heat
raising the temperature inside the reactor R5. Effluent 177 exiting
reactor R5 is then cooled down by heat exchanger 179, and then
delivered to a third fixed bed hydrogenation reactor R7 having a
catalyst bed 183 inside. A portion of the phenol contained in the
reaction media is converted to cyclohexanone in reactor R7,
releasing a moderate amount of heat raising the temperature inside
the reactor R7. Effluent 185 exiting reactor R7 is then cooled down
by heat exchanger 187, and delivered to drum D1, where a vapor
phase 117a and a liquid phase 119 are obtained. By using multiple
reactors in the hydrogenation reaction zone, and the use of heat
exchangers between adjacent reactors and after each reactor,
temperatures inside the reactors R3, R5, and R7 are each
independently maintained in a range from 140.degree. C. to
300.degree. C. (preferably about 220.degree. C. to about
260.degree. C., such as about 240.degree. C.), and the absolute
pressures inside reactors R3, R5, and R7 are each independently
maintained in a range from 375 kPa to 1200 kPa (preferably about
1000 to about 1200 kPa, such as about 1134 kPa). In general, higher
temperature favors the production of cyclohexanol over
cyclohexanone. Thus, it is highly desirable that the hydrogenation
is conducted at a temperature no higher than 220.degree. C.
[0126] FIG. 6 is a schematic diagram showing a portion of a
process/system similar to the process/system shown in FIGS. 1-5,
but comprising modified fluid communications between and/or within
the first distillation column T1 and the hydrogenation reactor R1.
In this figure, two middle effluents, including a first middle
effluent 107a and a second middle effluent 107b, are drawn from the
side of the first distillation column T1. The two effluents 107a
and 107b have differing compositions, and are combined to form a
feed 107, which is then combined with hydrogen feed streams 111 and
117b and delivered to the hydrogenation reactor(s). Drawing two
middle effluents with different compositions at different locations
have unexpected technical advantages. It was found that if only one
middle effluent is drawn from a single location on column T1,
certain undesirable components, such as hydroxycyclohexanone(s),
can accumulate in column T1. It is believed that
hydroxycyclohexanone(s) can undergo dehydration to form
cyclohexenone, which can cause fouling inside column T1. By drawing
middle effluents at different height locations on the column, one
can effectively reduce the accumulation of such undesirable
components and the probability of fouling inside the column.
[0127] FIG. 7 is a schematic diagram showing a portion of an
exemplary process/system of the present disclosure similar to those
shown in FIGS. 1-6, but comprising an anterior sorbent bed SBa
before the first distillation column T1 configured for removing at
least a portion of the S-containing components and/or the light
components (especially catalyst poison components) from a crude
feed (crude mixture) to reduce or prevent catalyst poisoning in the
hydrogenation reactor. A preferred anterior sorbent bed SBa
according to some embodiments comprises an Amberlyst.RTM. A21
sorbent bed, although other sorbent beds (e.g., a stronger basic
ion exchange resin such as Amberlyst.RTM. A26) could be used in
addition or instead. A crude mixture feed stream 102 is first
passed through the sorbent bed SBa, in which a basic solid-phase
sorbent material described above is installed. Alternatively, where
the total concentration of catalyst poison components (e.g., the
S-containing components and other light components capable of
poisoning the hydrogenation catalyst) in the crude mixture stream
102 is exceedingly high, an anterior distillation column (not
shown) may be used before the anterior sorbent bed SBa, so as to
remove a portion of the catalyst poison components from the first
mixture fed into the first distillation column Instead or in
addition, one or more additional anterior sorbent beds (also not
shown in FIG. 7) may be utilized, any one or more of which may be
the same or different from the anterior sorbent bed SBa. For
instance, a suitable additional anterior sorbent bed could comprise
a nickel sorbent, an ion exchange resin, and/or an activated carbon
bed. Such sorbents may remove one or more S-containing components,
and/or other catalyst poison components, and/or color bodies (i.e.,
impurities that impart some coloration to the feed stream 102).
Desirably, upon treatment by the anterior sorbent bed SBa (and/or
the optional anterior distillation column, and/or any one or more
additional anterior sorbent beds), concentrations of catalyst
poison components capable of poisoning the hydrogenation catalyst
is reduced significantly in effluent 107 compared to in feed 102.
Thus, in the embodiment shown in FIG. 7, the ratio of concentration
of catalyst poison components in the effluent 107 to the
concentration of said components in the feed 102 is within the
range of about 0.001 to 0.5, preferably about 0.001 to about 0.1,
such as 0.001 to 0.1. For instance, the ratio of concentration of
sulfuric acid in feed 102 to concentration of sulfuric acid in
effluent 107 is preferably within the range of about 0.001 to about
0.1, such as 0.001 to 0.1.
[0128] FIG. 8 shows an alternative to the configuration of FIG. 7.
In this figure, instead of placing an anterior sorbent bed SBa
before the first distillation column T1, a posterior sorbent bed
SBp is placed behind column T1, which receives the first middle
effluent 107 as a feed, produces a treated stream 195 depleted or
low in S-containing components and/or any one or more other
catalyst poison components such as light acids. A preferred
posterior sorbent bed SBp comprises an Amberlyst.RTM. A26 ion
exchange resin, referenced previously, although other sorbent beds,
such as other ion exchange resins (e.g., Amberlyst.RTM. A21) may be
used. The treated stream 195 is then delivered to the hydrogenation
reactor as a portion or all of the hydrogenation feed 151 together
with hydrogen feeds 111 and 117b. Alternatively, where the total
concentration of the catalyst poison components (such as the
S-containing components and/or other poisons) in the first middle
effluent 107 is exceedingly high (and/or where concentrations of
other impurities with different volatilities than phenol and
cyclohexanone in the first middle effluent 107 are exceedingly
high) a posterior distillation column (not shown) may be installed
before or after (that is, upstream of or downstream of,
respectively) the sorbent bed SBp, and effluent 107 may be treated
by both the posterior distillation column and the posterior sorbent
bed SBp before being fed to the hydrogenation reactor R1 as at
least a portion of the hydrogenation feed. Such a posterior
distillation column may be used to remove either light or heavy
components relative to the phenol and cyclohexanone in the first
middle effluent 107.
[0129] Further, other treatment options may be present instead of
or in addition to the posterior distillation column (also not
shown). For example, one or more additional posterior sorbent beds
may be utilized, any one or more of which may be the same or
different from the posterior sorbent bed SBp. Preferably, at least
one additional posterior sorbent bed is different from the
posterior sorbent bed SBp. For instance, a particularly suitable
additional posterior sorbent bed comprises a nickel sorbent. Such a
sorbent may remove S-containing components and/or other catalyst
poison components from the effluent 107. It may also remove color
bodies (e.g., trace byproducts that impart some degree of
coloration to the effluent 107). Alternatively or in addition, at
least one additional posterior sorbent bed may comprise an
activated carbon sorbent. Desirably, upon treatment by one or more
of (i) the posterior sorbent bed SBp, (ii) the posterior
distillation column, and (iii) one or more additional posterior
sorbent beds, concentrations of S-containing components capable of
poisoning the hydrogenation catalyst are reduced significantly in
the hydrogenation feed compared to in effluent 107. Preferably,
concentrations of any other impurities, including other catalyst
poison components and/or impurities having different volatilities
from phenol and cyclohexanone, are also reduced. For instance, in
the embodiment shown in FIG. 8 (employing a posterior sorbent bed
SBp), the ratio of concentration of catalyst poison components
(including S-containing components and other light components
capable of poisoning the hydrogenation catalyst) in the effluent
107 to the concentration of said components in the hydrogenation
feed is within the range of about 0.001 to 0.5, preferably about
0.001 to about 0.1, such as 0.001 to 0.1. For instance, the ratio
of concentration of sulfuric acid in the hydrogenation feed to
concentration of sulfuric acid in effluent 107 is preferably within
the range of about 0.001 to about 0.1, such as 0.001 to 0.1.
[0130] If necessary, in some embodiments, both (i) the anterior
treatment mechanism described in connection with FIG. 7 (e.g., one
or both of the anterior distillation column and the anterior
sorbent) and (ii) the posterior treatment mechanism described in
connection with FIG. 8 (e.g., one or more of the posterior
distillation column, the posterior sorbent bed, and the one or more
additional posterior sorbent beds) may be used to prevent catalyst
poison components (including the S-containing components) from
entering into the hydrogenation reactor(s) at an unacceptably high
concentration. The anterior and posterior sorbents, and/or the
optional additional posterior sorbent(s), can be the same or
different, and may each independently be selected from: massive
nickel, activated carbon, ion exchange resins (such as strong and
weak anion resins which are usually amine based), clay, kaolin,
silica sorbents, alumina sorbents, molecular sieves, (i) oxides of
alkali metals, alkaline earth metals, and zinc; (ii) hydroxides of
alkali metals, alkaline earth metals, and zinc; (iii) carbonates of
alkali metals, alkaline earth metals, and zinc; (iv) bicarbonates
of alkali metals, alkaline earth metals, and zinc; (v) complexes of
two or more of (i), (ii), (iii), and (iv); (vi) solid amines; (vii)
ion-exchange resins; and (viii) mixtures and combinations of two or
more of (i), (ii), (iii), (iv), (v), (vi), and (vii). The sorbents
may remove impurities such as catalyst poison components (including
the S-containing components) by physical absorption or adsorption,
extraction, and/or chemical reactions. Massive nickel is
particularly useful for removing S-containing and N-containing
poison components. However, a basic, solid-phase sorbent material
such as those described above is preferable for removing sulfuric
acid. A basic ion exchange resin is particularly preferable for
removing acid species and/or S-containing species.
[0131] FIG. 9 is a schematic diagram showing a portion of a
process/system similar to those shown in FIGS. 1-8 comprising a
side stripper column T6 after the cyclohexanone purification column
T2, configured to reduce amounts of light components from the final
cyclohexanone product. In this figure, the first upper effluent 105
comprising primarily cyclohexanone and light components obtained
from the first distillation column T1 and from the upper anterior
stripper effluent, if any, is delivered to cyclohexanone
purification column T2, where three effluents are obtained: a
second upper effluent 121 rich in light components such as water
and methylcyclopentanone and depleted in cyclohexanone and
cyclohexanol, a second middle effluent 123 rich in cyclohexanone
and depleted in light components and cyclohexanol, and a second
lower effluent 125 rich in cyclohexanol. Effluent 121 is first
cooled down by a heat exchanger 197, then delivered to a separation
drum D2 to obtain a liquid phase 199, which is recycled to column
T2, and a vapor phase 201, which is cooled again by a heat
exchanger 203, and delivered to another separation drum D3 to
obtain a liquid phase which is partly recycled as stream 205 to
drum D2, and partly delivered to storage S5, and a vapor phase 206
which can be purged. Effluent 123 is delivered to a side stripper
T6 where the following streams are produced: a substantially pure
cyclohexanone stream 211 in the vicinity of the bottom thereof,
which is delivered to a storage S7; and a light component stream
209, which is recycled to the column T2 at a location above
123.
[0132] Additional post-hydrogenation treatment (e.g., of a phenol
hydrogenation reaction effluent such as effluent 127 of FIG. 1) is
also contemplated in some embodiments. For instance, similar to the
embodiment of FIG. 9 (comprising further treatment by distillation
and/or stripping of cyclohexanone from first distillation column
T1), the product effluent from phenol hydrogenation (e.g.,
hydrogenation from reactor R1) may be subjected to one or more
distillation procedures. Such additional distillation could take
place in additional distillation columns, or could be effected by
providing at least a portion of such phenol hydrogenation effluent
to one or more of the first distillation column T1 or the
cyclohexanone purification column T2 of the various embodiments
just described. However, in any post-treatment of the
cyclohexanone, particularly of a stream comprising the phenol
hydrogenation reaction effluent, the stream should preferably not
be subjected to temperatures in excess of 280.degree. F.
(137.8.degree. C.), as it has been found that subjecting a phenol
hydrogenation effluent to such temperatures may substantially
increase the amount of cyclohexene present in the final product.
Preferably, the product of any phenol hydrogenation is not
subjected to temperatures in excess of 250.degree. F.
(121.1.degree. C.), most preferably not in excess of 235.degree. F.
(112.8.degree. C.), so as to minimize or avoid the formation of
additional cyclohexene that could be present in the final product
cyclohexanone composition. This includes operation of a
distillation column such that temperature at or below the
withdrawal point of a cyclohexanone-containing stream is in excess
of the aforementioned temperatures, and further includes operation
of a reboiler associated with any such distillation column, through
which a product stream or a portion of a product stream may
pass.
Cyclohexanone Compositions
[0133] In various embodiments, the methods and/or systems described
herein create compositions that are rich in cyclohexanone (also
referred to as cyclohexanone compositions).
[0134] Preferably, the cyclohexanone composition comprises at least
99 wt % cyclohexanone, based on the total weight of the
cyclohexanone composition. More preferably, the cyclohexanone
composition comprises at least 99.9 wt %, such as at least 99.94 wt
%, 99.95, or even 99.99 wt % cyclohexanone.
[0135] The cyclohexanone composition may further comprise one or
more cyclohexanone impurities selected from the following
compounds: benzene, cyclohexene, pentanal, cyclopentanol,
cyclohexanol, and phenol. As used herein, a "cyclohexanone
impurity" is any compound other than cyclohexanone or water, which
is typically acceptable in commercially available cyclohexanone
compositions in small amounts. In the present invention, water is
advantageously present in the cyclohexanone composition in amounts
of 0.15 wt % or less, such as 0.1 wt % or less, or 0.05 wt % or
less, based on total weight of the cyclohexanone composition.
Preferably, the total amount of cyclohexanone impurities is 500
wppm or less, more preferably 200 wppm or less, most preferably 150
wppm or less, or even 100 wppm or less, each wppm being based upon
the total weight of the cyclohexanone composition.
[0136] The cyclohexanone composition may comprise any one or more,
two or more, three or more, or four or more of such cyclohexanone
impurities. In particular embodiments, the cyclohexanone
composition comprises one or both of pentanal and cyclopentanol.
Compositions of such embodiments may also or instead comprise one
or both of cyclohexene and cyclohexanol. The combined amount of
cyclohexanone impurities in such embodiments is 200 wppm or less,
preferably 100 wppm or less.
[0137] In certain embodiments, the cyclohexanone composition may
consist of cyclohexanone, 0.15 wt % or less (preferably 0.1 wt % or
less, most preferably 0.05 wt % or less) water, and 500 wppm or
less (preferably 200 wppm or less, most preferably 100 wppm or
less) of one or more cyclohexanone impurities. The cyclohexanone
impurities in such embodiments are preferably selected from the
group consisting of: benzene, cyclohexene, pentanal, cyclopentanol,
cyclohexanol, and phenol. In certain embodiments, the cyclohexanone
impurities are selected from the group consisting of: cyclohexene,
pentanal, cyclopentanol, and cyclohexanol. Such compositions may
consist of any one, two, three, or four of the foregoing
impurities. In particular embodiments, the impurities consist of
cyclohexene, pentanal, cyclopentanol, and cyclohexanol. In yet
further particular embodiments, the impurities consist of (i)
cyclohexene, (ii) cyclopentanol or pentanal, and (iii)
cyclohexanol.
[0138] With respect to each aforementioned cyclohexanone impurity
in the cyclohexanone compositions of various embodiments: [0139]
Benzene may be present in an amount ranging from 0 to 20 wppm. For
instance, benzene may be present at 0 wppm to 5 wppm, preferably 0
wppm to 2.5 wppm. [0140] Cyclohexene may be present in an amount
ranging from 0 to 20 wppm. For instance, cyclohexene may be present
at 0 wppm to 15 wppm, such as 2.5 wppm to 15, or 5 wppm to 10 wppm.
[0141] Pentanal may be present in an amount ranging from 0 to 20
wppm, provided the high end of the range is greater than the low
end. For instance, pentanal may be present at 0 wppm to 10 wppm,
such as 1 wppm to 10 wppm, potentially 3 wppm to 7 wppm. [0142]
Cyclopentanol may be present in an amount ranging from 0 to 80
wppm. For instance, cyclopentanol may be present at 10 wppm to 50
wppm, such as 15 to 40 wppm, or 20 to 35 wppm. [0143] Cyclohexanol
may be present in an amount ranging from 0 to 80 wppm. For
instance, cyclohexanol may be present at 0 wppm to 40 wppm, such as
10 wppm to 40 wppm, for instance 12 wppm to 30 wppm, or 10 wppm to
20 wppm.
[0144] In various embodiments, any one or more of these
cyclohexanone impurities may have been generated in situ during a
process for making cyclohexanone (i.e., they were not added from an
external source). For instance, any one or more of the
cyclohexanone impurities may have been formed during the phenol
hydrogenation reaction. This is particularly likely for
cyclohexanone impurities such as cyclohexanol, cyclohexene, and
water. Additionally, any trace amount of unreacted phenol left over
from the hydrogenation reaction may remain as a cyclohexanone
impurity in some embodiments. Furthermore, in certain embodiments,
at least a portion of the cyclohexene may have been produced at
least in part during distillation or other treatment of all or part
of the phenol hydrogenation reaction effluent (i.e., the products
of hydrogenation of the hydrogenation feed comprising cyclohexanone
and phenol, such as takes place in R1 of FIG. 1). As already noted,
however, such amounts of cyclohexene may be minimized by avoiding
subjecting said all or part of the phenol hydrogenation reaction
effluent to temperatures in excess of 280.degree. F., preferably
avoiding temperatures in excess of 250.degree. F., most preferably
avoiding temperatures in excess of 235.degree. F.
[0145] Further, in various embodiments, all or at least part of the
pentanal and/or cyclopentanol may be formed either before or after
(i.e., upstream or downstream of, respectively) hydrogenation of
the hydrogenation feed comprising cyclohexanone and phenol. For
instance, in some embodiments in accordance with FIGS. 1, 7, and/or
8, pentanal and/or cyclopentanol may be formed in the first
distillation column T1. In yet other embodiments in accordance with
FIGS. 7 and/or 8, pentanal and/or cyclopentanol may be formed in a
posterior distillation column and/or an anterior distillation
column used to pre-treat hydrogenation reaction feed. In yet
further embodiments, pentanal and/or cyclopentanol may be formed in
any distillation column or other treatment to which all or a
portion of the phenol hydrogenation reaction effluent is
subjected.
Uses of Cyclohexanone and Phenol
[0146] The cyclohexanone composition produced through the processes
disclosed herein may be used, for example, as an industrial
solvent, as an activator in oxidation reactions and in the
production of adipic acid, cyclohexanone resins, cyclohexanone
oxime, caprolactam, and nylons, such as nylon-6 and nylon-6,6.
Thus, further embodiments may include caprolactam produced using a
cyclohexanone composition according to any of the aforementioned
embodiments. Likewise, further embodiments may include nylon
produced using a cyclohexanone composition according to any of the
aforementioned embodiments. Similarly, methods according to some
embodiments may include producing one or both of caprolactam and
nylon using a cyclohexanone composition according to any of the
aforementioned embodiments.
[0147] The phenol produced through the processes disclosed herein
may be used, for example, to produce phenolic resins, bisphenol A,
.epsilon.-caprolactam, adipic acid, and/or plasticizers.
[0148] While the present invention has been described and
illustrated by reference to particular embodiments, those of
ordinary skill in the art will appreciate that the invention lends
itself to variations not necessarily illustrated herein. For this
reason, then, reference should be made solely to the appended
claims for purposes of determining the true scope of the present
invention.
[0149] The contents of all references cited herein are incorporated
by reference in their entirety.
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