U.S. patent application number 09/964750 was filed with the patent office on 2002-12-19 for method for preparing aromatic carboxylic acids from alkylaromatics by liquie-phase oxidation.
This patent application is currently assigned to KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY, KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. Invention is credited to Jun, Ki-Won, Kim, Young-Ho, Park, Sang-Eon, Raju, David B., Yoo, Jin S..
Application Number | 20020193631 09/964750 |
Document ID | / |
Family ID | 19707674 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020193631 |
Kind Code |
A1 |
Park, Sang-Eon ; et
al. |
December 19, 2002 |
METHOD FOR PREPARING AROMATIC CARBOXYLIC ACIDS FROM ALKYLAROMATICS
BY LIQUIE-PHASE OXIDATION
Abstract
The present invention relates to a method for preparing aromatic
carboxylic acid from alkylaromatics by liquid-phase oxidation. More
particularly, the present invention relates to a method for
preparing aromatic carboxylic acid from alkylaromatics by oxidation
in acetic acid as solvent with oxygen-containing gas in the
presence of cobalt/manganese/bromine complex catalyst, wherein
nickel and carbon dioxide in an appropriate amount are added to
increase an activity of cobalt/manganese/bromine complex catalyst.
Especially nickel has a synergistic effect with carbon dioxide and
maximize the formation of the desired product having the
corresponding carboxylic groups to the number of alkyl groups in a
reactant.
Inventors: |
Park, Sang-Eon; (Joong-ku,
KR) ; Yoo, Jin S.; (Flossmoor, IL) ; Jun,
Ki-Won; (Yusung-ku, KR) ; Raju, David B.;
(Yusung-ku, KR) ; Kim, Young-Ho; (Youngdong-kun,
KR) |
Correspondence
Address: |
Finnegan, Henderson, Farabow
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Assignee: |
KOREA INSTITUTE OF SCIENCE AND
TECHNOLOGY
|
Family ID: |
19707674 |
Appl. No.: |
09/964750 |
Filed: |
September 28, 2001 |
Current U.S.
Class: |
562/416 |
Current CPC
Class: |
C07C 51/265 20130101;
C07C 51/265 20130101; C07C 63/16 20130101; C07C 51/265 20130101;
C07C 63/333 20130101; C07C 51/265 20130101; C07C 63/36 20130101;
C07C 51/265 20130101; C07C 63/06 20130101; C07C 51/265 20130101;
C07C 63/40 20130101; C07C 51/265 20130101; C07C 63/24 20130101;
C07C 51/265 20130101; C07C 63/307 20130101; C07C 51/265 20130101;
C07C 63/26 20130101; C07C 51/265 20130101; C07C 63/38 20130101 |
Class at
Publication: |
562/416 |
International
Class: |
C07C 051/255 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2001 |
KR |
2001-17072 |
Claims
What is claimed is:
1. A process for preparing aromatic carboxylic acids by
liquid-phase oxidation with oxygen-containing gas of alkylaromatics
and its partial oxidized intermediates in the presence of
cobalt/manganese/bromine complex catalyst and in acetic acid as the
solvent, is characterized by addition of nickel and carbon
dioxide.
2. The process for preparing aromatic carboxylic acids according to
claim 1, wherein the atomic weight ratio of said nickel/manganese
is in the range of 0.01 to 1.
3. The process for preparing aromatic carboxylic acids according to
claim 1, wherein the applied amount of said oxygen is in the range
of 2 to 75% (v/v) relative to the total gas amount.
4. The process for preparing aromatic carboxylic acids according to
claim 1, wherein the applied amount of said carbon dioxide is in
the range of 1 to 90% (v/v) relative to the total gas amount.
5. The process for preparing aromatic carboxylic acids according to
claim 1, wherein said alkylaromatic is selected from the group
consisting of toluene, o-xylene, m-xylene, p-xylene,
pseudocumene(1,2,4-trimethylbenzen- e),
mesitylene(1,3,5-trimethylbenzene),
durene(2,3,5,6-tetramethylnaphthal- ene), methylnaphthalene,
2,6-dimethylnaphthalene and 4,4'-dimethylbiphenyl.
6. The process for preparing aromatic carboxylic acids according to
claim 1, wherein said aromatic carboxylic acid is selected from the
group consisting of benzoic acid, phthalic acid, isophthalic acid,
terephthalic acid, trimellitic acid, trimesic acid, pyromellitic
acid, carboxylnaphthalic acid, 2,6-dicarboxynaphthalic acid and
4,4'-dicarboxybiphenylic acid.
7. The process for preparing aromatic carboxylic acids according to
claim 1, wherein said carbon dioxide is periodically or continually
applied in vapor- or liquid-phase.
8. The process for preparing aromatic carboxylic acids according to
claim 7, wherein said carbon dioxide is recycled after mixing with
fresh gas or reaction waste containing remained oxygen and carbon
dioxide, when it is applied in vapor-phase.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a method for preparing
aromatic carboxylic acids from alkylaromatics by liquid-phase
oxidation. More particularly, the present invention relates to a
method for preparing aromatic carboxylic acids from alkylaromatics
by oxidation in acetic acid as solvent with oxygen-containing gas
in the presence of cobalt/manganese/bromine complex catalyst,
wherein nickel and carbon dioxide are added in an appropriate
amount to increase an activity of cobalt/manganese/bromine complex
catalyst. Especially nickel has a synergistic effect with carbon
dioxide and maximize the formation of the desired product having
the corresponding carboxylic groups to the number of alkyl groups
in a reactant.
[0002] The first liquid-phase oxidation in place of vapor-phase
oxidation used in a preparation of aromatic carboxylic acid was
introduced in U.S. Pat. No. 2,245,528 to perform at 100-320.degree.
C. under the pressure to keep a saturated fatty acid solvent in
liquid state and in the presence of metal catalyst having several
valances. An activity was the most with cobalt among metals and
accelerated by adding ketones or aldehydes. However, this method
converts only one alkyl group of mono-, di-, or trimethyl benzene
to benzene monocarboxylic acids such as benzoic acid, toluic acid,
and dimethyl benzoic acid.
[0003] Other liquid-phase oxidations of alkyl aromatics at an
elevated temperature and pressure and in the presence of catalyst
have been disclosed to convert all the alkyl groups to the
corresponding carboxylic acids. Used catalysts are combinations of
bromine and transition metals, especially use of
cobalt/manganese/bromine complex catalyst in the oxidation of
p-xylene to terephthalic acid (U.S. Pat. No. 2,833,816). Further,
preparations of benzene di or tricarboxylic acid from di or
trimethyl benzene such as p-xylene, m-xylene or pseudocumene
(1,2,4-trimethyl benzene) by oxidation have been developed and
widely commercially applied (U.S. Pat. Nos. 5,041,633 and
5,081,290). The prepared aromatic carboxylic acids after purified
have been using as raw materials to produce polyesters, fibers,
films and the like.
[0004] However, the use of cobalt/manganese/bromine complex
catalyst has some drawbacks in side-reactions, expensive cost,
difficulties in treatment and sedimentation. Since reduced reaction
time to produce aromatic carboxylic acids will ensure an
improvement of productivity and manufacturing cost, development of
efficient catalysts and processes has been constantly progressing.
Even now, there is no better catalyst than cobalt/manganese/bromine
complex catalyst.
[0005] Development has been continued to improve an activity of a
catalyst by adding other components. Nickel has been used in
liquid-phase oxidation of dimethyl benzene or pseurocumene with
molecular oxygen but cobalt was not added (U.S. Pat. No.
4,786,753). Nickel has been also used in liquid-phase oxidation of
p-xylene with peroxide in the presence of cobalt/manganese/bromine
complex catalyst (KR Patent 2000-41505) but the activity was worse
than that of cobalt/manganese/bromine complex catalyst.
[0006] On the other hand, since liquid-phase oxidation of alkyl
aromatics in the presence of a stoichiometric excess of oxygen- or
highly pure oxygen-containing gas is susceptible to explosion for
formation of flammable gas, carbon dioxide is used to reduce a risk
of flammability or explosion. It is further known that it does not
affect the activity of the reaction (U.S. Pat. No. 5,693,856 and EP
Patent 0785183 A2). Recently carbon dioxide has been used with
cobalt/manganese/bromine complex catalyst (KR Patent Publication
2000-67444) and additionally with alkali metal or alkali earth
metal (KR Patent Publication 2000-41507) to improve the reaction
efficiency in the preparation of aromatic carboxylic acid via
liquid-phase oxidation. However, the development of metal or
non-metal component to be combined optimally with carbon dioxide is
highly demanded to improve the reaction efficiency largely.
SUMMARY OF THE INVENTION
[0007] The present invention has been completed with the
development of optimal combination of carbon dioxide and nickel,
which exhibits synergistic effect, in the preparation of aromatic
carboxylic acids by liquid-phase oxidation in the presence of
cobalt/manganese/bromine complex catalyst to remarkably improve
reaction efficiency due to increase in the reaction rate of the
oxidation.
[0008] An object of the present invention is to provide a method
for preparing aromatic carboxylic acids, which is highly efficient
in the presence of commercial cobalt/manganese/bromine complex
catalyst with carbon dioxide and nickel.
DETAILED DESCRIPTION OF THE INVENTION
[0009] In the preparation of aromatic carboxylic acids by
liquid-phase oxidation of alkylaromatics and partially oxidized
intermediates with oxygen-containing gas in the presence of
cobalt/manganese/bromine complex catalyst and in acetic acid as the
solvent, the present invention is characterized in that nickel and
carbon dioxide are used in the preparation of aromatic carboxylic
acids. Especially, nickel and carbon dioxide enhance each other's
promotional effect, showing namely synergistic effect.
[0010] The present invention is described in detail as set forth
hereunder.
[0011] The present invention uses an appropriate amount of carbon
dioxide and nickel in the conventional liquid-phase oxidization of
alkylaromatics which is performed by using oxygen-containing gas in
the presence of cobalt/manganese/bromine complex catalyst and in
acetic acid as the solvent to produce aromatic carboxylic acids,
thus provides some advantages in that the reaction efficiency with
increases in the reaction rate and reaction temperament is highly
improved, and the selectivity toward the product polycarboxylic
acids is largely increased due to a sharp decrease in the formation
of partial oxidized intermediates.
[0012] The present invention is described in more detail in
accordance with addition components and reaction conditions as set
forth hereunder. The addition components are alkylaromatics,
oxygen-containing gas, cobalt/manganese/bromine complex catalyst,
and reaction activators of nickel and carbon dioxide.
[0013] The alkylaromatics are the aromatic compounds having at
least one alkyl group. Examples are toluene, o-xylene, m-xylene,
p-xylene, pseudocumene(1,2,4-trimethylbenzene),
mesitylene(1,3,5-trimethylbenzene),
durene(2,3,5,6-tetramethylnaphthalene), methylnaphthalene,
2,6-dimethylnaphthalene, 4,4'-dimethylbiphenyl and an intermediate
thereof. These alkylaromatic compounds are converted to the
corresponding aromatic carboxylic acids, benzoic acid, phthalic
acid, isophthalic acid, terephthalic acid, trimellitic acid,
trimesic acid, pyromellitic acid, carboxylnaphthalic acid,
2,6-dicarboxynaphthalic acid and 4,4'-dicarboxybiphenylic acid.
[0014] It is prefer to use manganese/cobalt in the atomic weight
ratio range of 0.1-5, preferably 0.5-3 in cobalt/manganese/bromine
complex catalyst. It is further prefer to use
bromine/(manganese+cobalt) in the atomic weight ratio range of
0.1-5, preferably 0.5-2. Cobalt is used 50-10,000 ppm relative to
the total amount of reactants, preferably 100-1,000 ppm. Any
bromine compound such as HBr, Br.sub.2, tetrabromoethane and benzyl
bromide may be used as a source of bromine. As sources of manganese
and cobalt, any compound being soluble in a used solvent may be
possible (e.g. acetates, carbonates, acetate tetrahydrates and
bromides). It is prefer to have the atomic weight ratio of
nickel/manganese in the range of 0.01-1. If the weight ratio is
higher which means more amount of nickel than preferred is used,
the other catalyst compounds could not act as the catalyst.
[0015] Reaction gas used in the present invention is an oxygen or a
mixture gas of oxygen and inert gas such as nitrogen. Amount of
oxygen is in the range of 2-75% (v/v) to the total gas amount.
Carbon dioxide is also used to activate the reaction efficiency in
the range of 1-90% (v/v) to the total gas amount, preferably 10-85%
(v/v). If the amount of carbon dioxide is used less than 1% (v/v),
it is impossible to obtain the desired effect. On the other hand,
if it is used more than 90% (v/v), it is impossible to perform
smooth oxidation due to low concentration of oxygen. The carbon
dioxide is applied periodically or continually in the vapor or
liquid reaction medium. When it is applied into the vapor reaction
medium, it is recycled after mixing with fresh gas or reaction
waste containing remained oxygen and carbon dioxide.
[0016] Aromatic carboxylic acids of the present invention are
prepared by batch or continuous process. Preferred temperature is
in the range of 100-255.degree. C., more preferably 170-210.degree.
C. If the temperature is lower than 100.degree. C., the reaction
rate is too slow to be practical. On the other hand, if is higher
than 255.degree. C., it is not economical due to side reactions.
Reaction pressure is used to keep alkylaromatic compounds, its
intermediates, and solvent in partially liquid state and preferably
1-35 atm of gauge pressure, more preferably 8-30 atm.
[0017] Now, the invention is described in more detail with
reference to the following Examples, to which, however, the
invention is not restricted without departing from the spirit and
scope thereof.
[0018] Example 1 and Comparative Examples 1 to 7 are the
preparation of terephthalic acid by oxidation of p-xylene. Reaction
efficiencies and yields of terephthalic acid and partially oxidized
intermediate (p-toluic acid) are compared.
EXAMPLE 1
[0019] p-Xylene, acetic acid and catalyst were placed in 150 ml of
titan pressure reactor. Total amount of reactants was 30.42 g and
the ratio of p-xylene and acetic acid was 17:83. Each amount was
899 ppm for cobalt, 1170 ppm for manganese and 2990 ppm for bromine
in cobalt/manganese/bromine complex catalyst based to the total
weight of reactants. Cobalt bromide was used for sources of cobalt
and bromine. Manganese acetate tetrahydrate was used as a source of
manganese. 163 ppm of nickel was used based on the total weight of
reactants and nickel acetate tetrahydrate was used as a source of
nickel. The reaction mixture was stirred under nitrogen atmosphere
and heated to 170.degree. C. 50% of nitrogen gas and 33.3% of
carbon dioxide gas were applied and 16.7% of oxygen gas was then
applied instantaneously into the reaction mixture. The pressure was
applied to be total gauge pressure of 12 and fresh oxygen was
continually applied for consumed amount. The reaction mixture was
reacted for 180 min and then cooled. The oxide product was
collected and dried. The reaction condition, consumed amount of
oxygen, and yield of each terephthalic acid and p-toluic acid were
summarized in Table 1. When Example 1 was compared to Comparative
Example 3 wherein carbon dioxide and nickel were not used, the
reaction efficiency of Example 1 was improved 16.9% and the
formation of the desired product terephthalic acid was remarkably
increased. Further when Example 1 was compared to Comparative
Example 1 wherein only carbon dioxide was used, the reaction
efficiency was similar by using nickel but the selectivity toward
the formation of terephthalic acid was much higher than that of
Comparative Example 1. When Example 1 was compared to Comparative
Examples 1 and 2, in which either carbon dioxide or nickel was
added, and Comparative Example 3, in which either carbon dioxide or
nickel was not added, the increment of the yield of terephthalic
acid in Example 1 is much higher than the sum of each increment of
Comparative Examples 1 and 2, clearly exhibiting a synergistic
effect.
Comparative Example 1
[0020] The reaction was performed in the same manner as Example 1
but without addition of nickel. The reaction condition, consumed
amount of oxygen, and yield of each terephthalic acid and p-toluic
acid were summarized in Table 1. When Comparative Example 1 was
compared to Comparative Example 3 wherein carbon dioxide and nickel
were not used, the reaction efficiency of Comparative Example 1 was
improved 16.8% and the formation of the desired product
terephthalic acid was also increased.
Comparative Example 2
[0021] The reaction was performed in the same manner as Example 1
but without addition of carbon dioxide. The reaction condition,
consumed amount of oxygen, and yield of each terephthalic acid and
p-toluic acid were summarized in Table 1. When Comparative Example
2 was compared to Comparative Example 3 wherein carbon dioxide and
nickel were not used, the reaction efficiency of Comparative
Example 2 was similar but the formation of the desired product
terephthalic acid was increased.
Comparative Example 3
[0022] The reaction was performed in the same manner as Example 1
but without addition of carbon dioxide and nickel. Therefore 83.3%
of nitrogen and 16.7% of oxygen were applied into the reaction
mixture. The reaction condition, consumed amount of oxygen, and
yield of each terephthalic acid and p-toluic acid were summarized
in Table 1. Both reaction efficiency and formation of the desired
product terephthalic acid was considerably low.
Comparative Example 4
[0023] The reaction was performed in the same manner as Example 1
except that the reaction was performed for 120 min instead of 180
min. The reaction condition, consumed amount of oxygen, and yield
of each terephthalic acid and p-toluic acid were summarized in
Table 1. When Comparative Example 4 was compared to Comparative
Example 5 wherein only carbon dioxide was not used, the reaction
efficiency was increased 46.5% and the formation of the desired
product terephthalic acid was also increased.
Comparative Example 5
[0024] The reaction was performed in the same manner as Example 4
but without addition of carbon dioxide and nickel. Therefore 83.3%
of nitrogen and 16.7% of oxygen were applied into the reaction
mixture. The reaction condition, consumed amount of oxygen, and
yield of each terephthalic acid and p-toluic acid were summarized
in Table 1. Both reaction efficiency and formation of the desired
product terephthalic acid was considerably low.
Comparative Example 6
[0025] The reaction was performed in the same manner as Example 1
except that the reaction was performed for 60 min instead of 180
min. The reaction condition, consumed amount of oxygen, and yield
of each terephthalic acid and p-toluic acid were summarized in
Table 1. When Comparative Example 6 was compared to Comparative
Example 7 wherein only carbon dioxide was not used, the reaction
efficiency was increased 11.7% and the formation of the desired
product terephthalic acid was also increased.
Comparative Example 7
[0026] The reaction was performed in the same manner as Example 6
but without addition of carbon dioxide and nickel. Therefore 83.3%
of nitrogen and 16.7% of oxygen were applied into the reaction
mixture. The reaction condition, consumed amount of oxygen, and
yield of each terephthalic acid and p-toluic acid were summarized
in Table 1. Both reaction efficiency and formation of the desired
product terephthalic acid was considerably low.
1 TABLE 1 Consumed Yield (mole %) Temp. Time CO.sub.2 Nickel Oxygen
Terephthalic p-toluic Category (.degree. C.) (min) (%) (ppm)
(mmol)* acid acid Ex. 1 170 180 33.3 163 97.5 56.2 31.2 Comp. 1 170
180 33.3 0 97.4 34.8 36.9 Ex. 2 170 180 0 163 83.7 25.2 40.9 3 170
180 0 0 83.4 17.7 47.9 4 170 120 33.3 0 67.7 19.4 28.2 5 170 120 0
0 46.2 3.1 31.0 6 170 60 33.3 0 42.8 2.2 28.4 7 170 60 0 0 38.3 0.4
23.3 Theoretical oxygen equivalent: 145.8 mmol
[0027] In Example 2 and Comparative Examples 8 to 10 preparing
terephthalic acid from p-xylene, the reaction time was compared to
consume the same amount of oxygen.
EXAMPLE 2
[0028] The reaction was performed in the same manner as Example 1
except that a reaction temperature was 190.degree. C. and a gauge
pressure was 20 atm. 25% of oxygen, 30% of carbon dioxide and 45%
of nitrogen were applied. When 85% of theoretical oxygen equivalent
was consumed, the reaction was completed. The reaction time was 54
min which was decreased of 50% compared with that of Comparative
Example 10 wherein carbon dioxide and nickel were not used. The
amount of consumed oxygen was measured over the reaction time
wherein a consuming rate of oxygen was rapidly increased in the
initial stage. The formation of terephthalic acid was high. That
is, when carbon dioxide and nickel were used, both the reaction
efficiency and the formation of terephthalic acid were improved due
to reduced formation of side product.
Comparative Example 8
[0029] The reaction was performed in the same manner as Example 2
but without addition of nickel. The time to consume 85% of
theoretical oxygen equivalent was 84 min. The reaction time was
decreased, and the consuming rate of oxygen and the formation of
terephthalic acid were increased compared with those of Comparative
Example 10 wherein carbon dioxide and nickel were not used.
Comparative Example 9
[0030] The reaction was performed in the same manner as Example 2
but without addition of carbon dioxide. The time to consume 85% of
theoretical oxygen equivalent was 90 min. The reaction time was
decreased, and the consuming rate of oxygen and the formation of
terephthalic acid were increased compared with those of Comparative
Example 10 wherein carbon dioxide and nickel were not used.
Comparative Example 10
[0031] The reaction was performed in the same manner as Example 2
but without addition of carbon dioxide and nickel. Therefore, 25%
of oxygen and 75% of nitrogen were applied into the reaction
mixture. The time to consume 85% of theoretical oxygen equivalent
was 110 min. The formation of terephthalic acid was the lowest
compared with other Example 2 and Comparative Examples 8 and 9.
2 TABLE 2 Consumed oxygen Yield (mol%) Temp Time CO.sub.2 Nickel
(mmol)** Terephthalic p-toluic Category (.degree. C.) (min)* (%)
(ppm) 15 min 30 min 45 min acid acid Ex. 2 190 54 30.0 163 37 8 80
6 109 1 86.3 0 8 Comp. 8 190 84 30.0 0 35 1 68.1 91 1 85.4 0 0 Ex.
9 190 90 0 163 35.8 69 0 96 3 84.7 0 3 10 190 110 0 0 20.5 53.3 77
4 82.7 3 8 *Time to consume 85% of theoretical oxygen equivalent
where the reaction was completed) **Theoretical oxygen equivalent.
145.8 mmol
[0032] In Example 3 and Comparative Examples 11-13 preparing
terephthalic acid from m-xylene, yield and reactivity were
compared.
EXAMPLE 3
[0033] The reaction was performed in the same manner as Example 2
except that m-xylene was used and reaction was performed for 60
min. 98.9 mmol of oxygen was consumed for 60 min. The reaction
efficiency was increased 4.1% and formation of isophthalic acid was
also increased compared with Comparative Example 13 wherein carbon
dioxide and nickel were not used.
Comparative Example 11
[0034] The reaction was performed in the same manner as Example 3
but without addition of nickel. 95.7 mmol of oxygen was consumed
for 60 min. Both reaction efficiency and formation of isophthalic
acid were increased compared with Comparative Example 13 wherein
carbon dioxide and nickel were not used.
Comparative Example 12
[0035] The reaction was performed in the same manner as Example 3
but without addition of carbon dioxide and nickel. 95.4 mmol of
oxygen was consumed for 60 min. Both reaction efficiency and
formation of isophthalic acid were slightly increased compared with
Comparative Example 13 wherein carbon dioxide and nickel were not
used.
Comparative Example 13
[0036] The reaction was performed in the same manner as Example 2
but without addition of nickel. Therefore, 25% of oxygen and 75% of
nitrogen were applied into the reaction mixture. 95.0 mmol of
oxygen was consumed for 60 min. Both reaction efficiency and
formation of isophthalic acid were the lowest compared with other
Example 3 and Comparative Examples 11 and 12.
3 TABLE 3 Consumed Yield (mole %) Temp. Time CO.sub.2 Nickel Oxygen
Terephthalic p-toluic Category (.degree. C.) (min) (%) (ppm)
(mmol)** acid acid Ex. 3 190 60 30.0 163 98.9 54.9 21.4 Comp. 11
190 60 30.0 0 95.7 53.0 17.2 Ex. 12 190 60 0 163 95.4 51.1 17.3 13
190 60 0 0 95.0 50.4 10.4 **Theoretical oxygen equivalent 145.8
mmol
[0037] As described above, it was noted that in the preparation of
aromatic carboxylic acids from alkylaromatics by oxidation in
acetic acid as solvent with oxygen-containing gas in the presence
of cobalt/manganese/bromine complex catalyst, the use of nickel and
carbon dioxide in an appropriate amount increases an activity of
cobalt/manganese/bromine complex catalyst. Especially nickel has a
synergistic effect with carbon dioxide and maximize the formation
of the desired product having the corresponding carboxylic groups
to the number of alkyl groups in a reactant.
* * * * *