# Patent

## Title
Process for producing organic carboxylic acid amides

## Abstract

The present invention relates to a process for producing organic carboxylic acid amides by nitrile hydrolysis of a nitrile compound at certain temperature and pressure in the presence of a catalyst to produce an organic carboxylic acid amide.

## Background
FIELD OF THE INVENTION
The present invention relates to a process for producing organic carboxylic acid amides by nitrile hydrolysis of a nitrile compound at a certain temperature in the presence of a catalyst to produce an organic carboxylic acid amide. In particular, the present invention relates to a process for producing α-hydroxyl carboxylic acid amides from α-hydroxyl nitrile compounds.
BACKGROUND TO THE INVENTION
Amide compounds have active chemical properties and are involved in various chemical reactions. They are important intermediates in the production of nitriles, amines, etc. and have many industrial uses. For example, acetamide and dimethylformide, which have high dielectric constants, are excellent solvents for many organic and inorganic substances and are widely used in various industries. Acetanilide is an intermediate in the production of sulfonamide medicines, urea is an important raw material for nitrogenous fertilizers and synthetic resins, and caprolactam is the monomer for synthesizing nylon 6.
Most amide compounds are obtained by heating to hydrolyze nitrile compounds in an acidic or basic aqueous solution. However, because amide compounds will continue hydrolyzing to carboxylic acid compounds, the selectivity of this process is not high. Recently, the use of solid acidic materials as a catalyst to solve the drawbacks of the prior art has been extensively discussed and studied, and many catalysts in different forms were successively developed and applied to the selective hydrolysis of nitrile compounds. The catalytic system for use in the hydrolysis of nitrile compounds includes various transition metal catalysts, including copper catalyst [Chem. Soc. Jpn., 44 (1971) 1440] [Bull. Chem. Soc. Jpn., 47 (1974) 1948], palladium catalyst [J. Mol. Catal., 12 (1981) 103], rhodium catalyst [J. Org. Chem., 57 (1992) 2521], platinum catalyst [J. Am. Chem. Soc., 95 (1973) 3030], cobalt catalyst [J. AM. Chem. Soc., 115 (1993) 3618], and nickel catalyst [Bull. Chem. Soc. Jpn., 47 (1974) 1948], which were successively reported to have certain activities when used in the selective hydrolysis of nitrile compounds. However, the aforementioned metal catalysts all cannot be used in industrial processes due to the complex catalytic system and severe reaction conditions.
Currently, manganese dioxide catalyst is the most-reported catalyst for the hydrolysis of nitrile compounds. It has a good catalytic activity for hydrolysis with respect to organic nitrile compounds, of which 6-type manganese dioxide has a higher reaction activity due to its higher surface area [J. Catal., 84 (1983) 267]. The use of manganese dioxide in the hydrolysis of 2-hydroxyisobutyronitrile into α-hydroxyisobutyramide was firstly disclosed in DE 2,131,813. U.S. Pat. No. 4,018,829 discloses the reduction of a heptavalent manganese compound into tetravalent δ-manganese dioxide in a basic environment in a manner of controlling the environmental acidity/basicity, and the use of δ-manganese dioxide as a catalyst for the hydrolysis of 2-hydroxyisobutyronitrile. JP 63-57534 and 63-57535 disclose the use of manganese dioxide in which zinc is incorporated or the use of manganese dioxide obtained by reducing potassium permanganate with a HCl solution, as a catalyst for the hydrolysis of 2-hydroxyisobutyronitrile. It seems that manganese dioxide has been successfully used in the hydrolysis of 2-hydroxyisobutyronitrile and has effectively eliminated the drawbacks of the prior art; however, because the catalytic activity of manganese dioxide is not high, a large amount of catalyst must be used in the process to achieve the desired production of α-hydroxyisobutyramdde. Further, because the reaction activity of manganese dioxide starts to decrease greatly within a very short time, there are also extensive researches and developments on long-life manganese dioxide with high catalytic activity at present. Related researches indicated that the catalytic activity of manganese dioxide is highly related to the preparation method and pretreatment temperature [Bull. Chem. Soc. Jpn., 59 (1986) 2983]. U.S. Pat. No. 4,950,801 discloses that a manganese dioxide catalyst having a large specific surface area, low crystallinity and an amorphous or a nearly amorphous state can be prepared in an acidic environment by introducing at least one kind of Groups IA and IIA metals into manganese dioxide. The modified manganese dioxide catalyst has a higher hydrolysis catalytic activity and a prolonged catalyst life. U.S. Pat. No. 4,987,256 proposes the simultaneous use of manganese (II) and manganese (VII) in a reduction-oxidation reaction to obtain manganese dioxide. The properties of manganese dioxide obtained by this process can be controlled more easily. Also, in the production of manganese dioxide, the sulfates of zirconium, vanadium or zinc are added, whereby the metal zirconium, vanadium or zinc is incorporated into manganese dioxide to improve the activity and life of the catalyst. U.S. Pat. No. 5,087,750 discloses an industrial process for producing α-hydroxyisobutyric acid amide using a fixed bed catalyst in a tubular reactor, which is more suitable for continuous operation, and also proposes that the addition of oxidizing agent in the reactant feed can facilitate prolonging the service lifetime of the manganese dioxide catalyst and increasing the yield of α-hydroxyisobutyric acid amide. U.S. Pat. No. 5,463,123 proposes that the pretreatment of the manganese dioxide catalyst and reducing agent before packing the catalyst in a reactor can suppress the clogging of the by-product oxamide in the catalyst bed during the process, whereby the stability of the catalyst is increased.
Promoting the catalytic activity of manganese dioxide, increasing the stability of the catalyst and prolonging the reaction lifetime of manganese dioxide are key points of the study on modification of the manganese dioxide catalyst. The aforementioned patents all either require using specific preparation processes and/or adding specific promoters to prepare a manganese dioxide catalyst in a specific form, or carrying out a pretreatment of the catalyst before its taking part in the reaction, and adding oxidizing agents during the process, which all result in increasing the complexity of catalyst preparation and reaction operation. In view of the drawbacks of the prior art, the present invention aims to develop a manganese dioxide catalyst that is easily produced, has a high stability and can achieve a commercial level effect within a shorter reaction time.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a process for producing organic carboxylic acid amides from nitrile compounds under a relatively mild reaction condition.
Another object of the present invention is to provide a manganese dioxide catalyst that is easily produced, has a high stability and can achieve a commercial level effect within a shorter reaction time.
According to the present invention, a catalyst comprising a metal oxide and a manganese dioxide active component supported on the metal oxide is used in the hydrolysis of various nitrile compounds to produce organic carboxylic acid amides.
The catalyst for the hydrolysis of nitrile compounds has a structure represented by the formula (I):

MnO2/MOx  (I)

in which M represents a metal of the first to third row transition elements and Groups IIIA and IVA of any valence number, and MOx represents its metal oxide form such as, for example, iron oxide, nickel oxide, cobalt oxide, niobium oxide, titanium oxide, copper oxide, aluminum oxide, and silicon oxide. MOx can be a single metal oxide or a mixture of various metal oxides.

According to the present invention, the molar ratio of the manganese dioxide active component to the metal oxide in the catalyst is 0.05-2, preferably 0.1-1.5, and most preferably 0.2-1.2. The catalyst is added in an amount that makes the molar ratio of manganese dioxide to the reacted nitrile compound be between 0.01 and 2, preferably between 0.05 and 1.5, and most preferably between 0.1 and 1.
The nitrile compound used in the present invention has a structure represented by the formula (II):




in which R1 and R2 can be selected from the same or different alkyl group or aryl group. Specifically, R1 can be selected from the group consisting of hydrogen atom, C1-12 alkyl group and C6-20 aryl group, and R2 can be selected from the group consisting of hydrogen atom, C1-12 alkyl group and C6-20 aryl group.

According to the present invention, the reaction temperature for the hydrolysis of nitrile compounds is from 30 to 160° C., preferably from 30 to 140° C., and most preferably from 30 to 120° C.; the reaction pressure is from 0 to 2 kg/cm2; and the reaction time is from 0.2 to 8 hours. The reaction is an equilibrium reaction, and the yield of the reaction depends on the kind and amount of the nitrile compound as used.
Compared with the aforementioned prior art, the use of the catalyst of a manganese dioxide active component supported on a metal oxide according to the present invention can effectively increase the dispersivity of the manganese dioxide active component and really promote its catalytic activity; also, as the manganese dioxide active component is protected by the metal oxide, its stability is enhanced and the selectivity of the reaction can thus be maintained so that a commercial level effect can be achieved within a shorter reaction time.
The features and effects of the present invention will be further explained with reference to the preferred embodiments below, which are, however, not intended to restrict the scope of the present invention.


DESCRIPTION OF PREFERRED EMBODIMENTS
The convertibility and selectivity used in the specification are calculated according to the following equations:

Convertibility (%)={[Concentration of Added Nitrile Compound−Concentration of Unreacted Nitrile Compound] (mol)/Concentration of Added Nitrile Compound (mol)}×100%

Selectivity (%)=[Concentration of Organic Carboxylic Acid Amide in the Product (mol)/Concentration of Consumed Nitrile Compound (mol)]×100%

The catalyst of the present invention is suitable to selective hydrolysis of various nitrile compounds. The following embodiments are provided to facilitate understanding of the contents of the present invention only but do not restrict the practical scope of the present invention.
COMPARATIVE EXAMPLE 1
(1) Preparation of Catalyst
In a 500-ml three-necked bottle, 21.11 g of potassium permanganate, 33.76 g of manganese sulfate, 14 g of a concentrated sulfuric acid solution and 270 g of deionized water were mixed evenly. After a reaction thereof for 3 hours at a temperature of 70° C., a suction filtration was performed. The product was rinsed with deionized water and then dried in a vacuum oven. Thus a desired MnO2 catalyst was obtained.
(2) Hydrolysis Test
A reaction of 15 g (0.176 mol) of 2-hydroxyisobutyronitrile, 10 g (0.172 mol) of acetone, 35 g (1.944 mol) of deionized water and 6 g (0.069 mol) of the MnO2 catalyst, placed in a 250-ml three-necked bottle, was carried out with a reflux method in a batch operation at a temperature of 60° C. and a rotation rate of 400 rpm. Samplings were conducted at 3 hours and 5 hours after the reaction was initiated. The product was analyzed with high pressure liquid chromatography. The result is shown in Table 1.
EXAMPLE 1
(1) Preparation of Catalyst
In a 500-ml three-necked bottle, 21.11 g of potassium permanganate, 8.647 g of cobalt oxide, 33.76 g of manganese sulfate, 14 g of a concentrated sulfuric acid solution and 270 g of deionized water were mixed evenly. After a reaction thereof for 3 hours at a temperature of 70° C., a suction filtration was performed. The product was rinsed with deionized water and then dried in a vacuum oven. Thus a desired MnO2/CO3O4 catalyst (Mn/Co molar ratio=1) was obtained.
(2) Hydrolysis Test
A reaction of 15 g (0.176 mol) of 2-hydroxyisobutyronitrile, 10 g (0.172 mol) of acetone, 35 g (1.944 mol) of deionized water and 11.537 g of the MnO2/CO3O4 catalyst (0.069 mol of Mn), placed in a 250-ml three-necked bottle, was carried out with a reflux method in a batch operation at a temperature of 60° C. and a rotation rate of 400 rpm. Samplings were conducted at 3 hours and 5 hours after the reaction was initiated. The product was analyzed with high pressure liquid chromatography. The result is shown in Table 1.











TABLE 1









Mn/
3 Hr
5 Hr















M Molar
Conv.

Conv.
Sel.


No.
Catalyst
Ratio
(%)
Sel. (%)
(%)
(%)





CEx. 1
MnO2
—
86.88
95.88
91.21
94.65


Ex. 1
MnO2/Co3O4
1
88.81
99.41
96.28
94.31





CEx. = Comparative Example


Ex. = Example






The experimental results in Table 1 show that manganese dioxide supported on a metal oxide can effectively promote the reaction activity of manganese dioxide, shorten the reaction time, maintain the selectivity of α-hydroxyisobutyramide, and achieve a commercial level effect within a reaction time of 3 hours.
EXAMPLES 2-7
(1) Preparation of Catalyst
The catalysts were prepared in the same manner as in Example 1, except that cobalt oxide in Example 1 was replaced with other metal oxides listed in Table 2, with the molar ratio of manganese to individual metal being 1.
(2) Hydrolysis Test
The hydrolysis tests were conducted in the same manner as in Example 1 with the MnO2/MOx catalysts having 0.069 mol of Mn (i.e. Mn/M molar ratio=1) used. The results are shown in Table 2.











TABLE 2









Mn/
3 Hr
5 Hr















M Molar
Conv.

Conv.



No.
Catalyst
Ratio
(%)
Sel. (%)
(%)
Sel. (%)





Ex. 2
MnO2/Nb2O5
1
86.76
95.32
91.98
95.60


Ex. 3
MnO2/NiO
1
74.10
90.41
92.48
90.39


Ex. 4
MnO2/TiO2
1
82.29
93.39
88.44
93.72


Ex. 5
MnO2/Fe2O3
1
80.18
92.69
89.17
93.93


Ex. 6
MnO2/Al2O3
1
59.34
83.24
82.48
85.57


Ex. 7
MnO2/SiO2
1
88.40
94.68
92.32
94.24





Ex. = Example






The experimental results in Table 2 show that different kinds of metal oxides can be used as a carrier supporting the manganese dioxide active component and maintain certain reaction activity levels.
EXAMPLES 8-9
(1) Preparation of Catalyst
The catalysts were prepared in the same manner as in Example 1, except that the added amount of cobalt oxide in Example 1 was altered to make the molar ratio of manganese to cobalt be 0.5 and 0.2, respectively.
(2) Hydrolysis Test
The hydrolysis tests were conducted in the same manner as in Example 1 with the MnO2/CO2O4 catalysts having 0.069 mol of Mn used. The results are shown in Table 3.











TABLE 3









Mn/
3 Hr
5 Hr















Co Molar
Conv.

Conv.



No.
Catalyst
Ratio
(%)
Sel. (%)
(%)
Sel. (%)
















Ex. 1
MnO2/Co3O4
1
88.81
99.41
96.28
94.31


Ex. 8
MnO2/Co3O4
0.5
82.74
92.19
94.21
94.65


Ex. 9
MnO2/Co3O4
0.2
70.80
92.06
85.14
92.35





Ex. = Example






The experimental results in Table 3 show that the added amount of the metal oxide will affect the reaction activity of the whole MnO2/MOx catalyst.
EXAMPLE 10
(1) Preparation of Catalyst
The catalyst was prepared in the same manner as in Example 1, except that cobalt oxide in Example 1 was replaced with a mixture of cobalt oxide and aluminum oxide in which the Co/Al molar ratio was equal to 1 while the molar ratio of manganese to the metal in the metal oxide was 1. Thus a desired MnO2/CO3O4—Al2O3 catalyst (Mn/(Co+Al) molar ratio=1, Co/Al molar ratio=1) was obtained.
(2) Hydrolysis Test
The hydrolysis test was conducted in the same manner as in Example 1 with the MnO2/CO3O4—Al2O3 catalyst having 0.069 mol of Mn used. The result is shown in Table 4.
EXAMPLES 11-12
(1) Preparation of Catalyst
The catalysts were prepared in the same manner as in Example 1, except that the Co/Al molar ratio in the mixture of cobalt oxide and aluminum oxide in Example 10 was altered to 0.33 and 0.20, respectively, while the molar ratio of manganese to the metal in the metal oxide remained 1. Thus a desired MnO2/CO3O4—Al2O3 catalyst (Mn/(Co+Al) molar ratio=1, Co/Al molar ratio=0.33) and MnO2/CO3O4—Al2O3 catalyst (Mn/(Co+Al) molar ratio=1, Co/Al molar ratio=0.20) were obtained.
(2) Hydrolysis Test
The hydrolysis tests were conducted in the same manner as in Example 1 with the MnO2/CO3O4—Al2O3 catalysts having 0.069 mol of Mn used. The results are shown in Table 4.












TABLE 4









Mn/(Co + Al)
Co/Al Molar
3 Hr
5 Hr














No.
Catalyst
Molar Ratio
Ratio
Conv. (%)
Sel. (%)
Conv. (%)
Sel. (%)





Ex. 1
MnO2/Co3O4
1
—
88.81
99.41
96.28
94.31


Ex. 10
MnO2/Co3O4—Al2O3
1
1
85.10
92.24
89.71
92.51


Ex. 11
MnO2/Co3O4—Al2O3
1
0.33
84.34
91.33
91.21
90.86


Ex. 12
MnO2/Co3O4—Al2O3
1
0.20
79.41
92.61
85.93
92.64





Ex. = Example






The experimental results in Table 4 show that the metal oxide for supporting manganese dioxide can be a single metal oxide or a mixture of various metal oxides.
COMPARATIVE EXAMPLE 2
(1) Preparation of Catalyst
The MnO2 catalyst was prepared in the same manner as in Comparative Example 1.
(2) Hydrolysis Test
The hydrolysis test was conducted in the same manner as in Comparative Example 1 with the MnO2 catalyst having 0.046 mol of Mn used. The result is shown in Table 5.
EXAMPLES 13-15
(1) Preparation of Catalyst
The MnO2/CO3O4 catalysts (Mn/Co molar ratio=1) were prepared in the same manner as in Example 1.
(2) Hydrolysis Test
The hydrolysis tests were conducted in the same manner as in Example 1 with the MnO2/MOx catalysts having 0.130 mol, 0.046 mol and 0.023 mol of Mn (Mn/M molar ratio=1) used. The results are shown in Table 5.












TABLE 5









Mn/Co Molar
MnO2/ACH
3 Hr
5 Hr














No.
Catalyst
Ratio
Molar Ratio
Conv. (%)
Sel. (%)
Conv. (%)
Sel. (%)





CEx. 1
MnO2
—
0.368
86.88
95.88
91.21
94.65


CEx. 2
MnO2
—
0.245
72.19
93.49
76.23
93.28


Ex. 13
MnO2/Co3O4
1
0.736
92.29
95.33
92.48
94.30


Ex. 1
MnO2/Co3O4
1
0.368
88.81
99.41
96.28
94.31


Ex. 14
MnO2/Co3O4
1
0.245
79.18
94.79
89.39
93.91


Ex. 15
MnO2/Co3O4
1
0.184
54.80
94.75
66.74
94.89





CEx. = Comparative Example


Ex. = Example






The experimental results in Table 5 show that manganese dioxide supported on a metal oxide can really facilitate promoting the catalytic activity, maintain the selectivity, and effectively shorten the reaction time or reduce the amount of used catalyst.
EXAMPLES 16-18
(1) Preparation of Catalyst
The MnO2/CO3O4 catalysts (Mn/Co molar ratio=1) were prepared in the same manner as in Example 1.
(2) Hydrolysis Test
The hydrolysis tests were conducted at temperatures of 50° C., 80° C. and 100° C. in the same manner as in Example 1. The results are shown in Table 6.












TABLE 6









Mn/Co Molar

3 Hr
5 Hr














No.
Catalyst
Ratio
Temp. (° C.)
Conv. (%)
Sel. (%)
Conv. (%)
Sel. (%)

















Ex. 16
MnO2/Co3O4
1
50
68.31
94.06
80.20
95.17


Ex. 1
MnO2/Co3O4
1
60
88.81
99.41
96.28
94.31


Ex. 17
MnO2/Co3O4
1
80
92.72
88.03
95.86
89.88


Ex. 18
MnO2/Co3O4
1
100
94.01
86.23
95.69
85.47





Ex. = Example






The experimental results in Table 6 show that the increase in reaction temperature can facilitate promoting the reaction rate but may result in the decrease of selectivity.
EXAMPLE 19
(1) Preparation of Catalyst
The MnO2/CO3O4 catalyst (Mn/Co molar ratio=1) was prepared in the same manner as in Example 1.
(2) Hydrolysis Test
A reaction of 12.53 g (0.176 mol) of 2-hydroxypropanenitrile, 10 g (0.172 mol) of acetone, 35 g (1.944 mol) of deionized water and 11.537 g of the MnO2/CO3O4 catalyst (0.069 mol of Mn), placed in a 250-ml three-necked bottle, was carried out with a reflux method in a batch operation at a temperature of 60° C. and a rotation rate of 400 rpm. Samplings were conducted at 3 hours and 5 hours after the reaction was initiated. The product was analyzed with high pressure liquid chromatography. The result is shown in Table 7.
EXAMPLE 20
(1) Preparation of Catalyst
The MnO2/CO3O4 catalyst (Mn/Co molar ratio=1) was prepared in the same manner as in Example 1.
(2) Hydrolysis Test
A reaction of 24.43 g (0.176 mol) of mandelonitrile, 10 g (0.172 mol) of acetone, 35 g (1.944 mol) of deionized water and 11.537 g of the MnO2/CO3O4 catalyst (0.069 mol of Mn), placed in a 250-ml three-necked bottle, was carried out with a reflux method in a batch operation at a temperature of 60° C. and a rotation rate of 400 rpm. Samplings were conducted at 3 hours and 5 hours after the reaction was initiated. The product was analyzed with high pressure liquid chromatography. The result is shown in Table 7.










TABLE 7









3 Hr
5 Hr













No.
Nitrile Compound
Catalyst
Conv. (%)
Sel. (%)
Conv. (%)
Sel. (%)





Ex. 1
2-hydroxyisobutyronitrile
MnO2/Co3O4
88.81
99.41
96.28
94.31


Ex. 19
2-hydroxypropanenitrile
MnO2/Co3O4
96.65
98.31
98.70
98.07


Ex. 20
mandelonitrile
MnO2/Co3O4
57.63
70.58
64.71
66.53





Ex. = Example






The experimental results in Table 7 show that the catalytic system of the present invention is suitable to the hydrolysis of various nitrile compounds to produce organic carboxylic acid amides.

## Claims

1. A process for producing organic carboxylic acid amides by nitrile hydrolysis of a nitrile compound in the presence of a catalyst to produce an organic carboxylic acid amide, wherein the catalyst comprises a manganese dioxide active component supported on Co3O4, and wherein the molar ratio of the manganese dioxide active component to the Co3O4 is 0.05:1 to 2:1.

2. The process according to claim 1, wherein the molar ratio of the manganese dioxide active component to the metal oxide is 0.1-1.5.

3. The process according to claim 2, wherein the molar ratio of the manganese dioxide active component to the metal oxide is 0.2-1.2.

4. The process according to claim 1, wherein the nitrile compound has a structure represented by the formula (II):



in which R1 and R2 are the same or different and are independently selected from the group consisting of hydrogen atom, C1-12 alkyl group and C6-20 aryl group.

5. The process according to claim 1, wherein the nitrile hydrolysis reaction is carried out at a temperature of from 30 to 160° C.

6. The process according to claim 5, wherein the nitrile hydrolysis reaction is carried out at a temperature of from 30 to 140° C.

7. The process according to claim 6, wherein the nitrile hydrolysis reaction is carried out at a temperature of from 30 to 120° C.

8. The process according to claim 1, wherein the nitrile hydrolysis reaction is carried out at a pressure of from 0 to 2 kg/cm2.

9. The process according to claim 1, wherein the catalyst is added in an amount that makes the molar ratio of manganese dioxide to the reacted nitrile compound be between 0.01 and 2.

10. The process according to claim 9, wherein the catalyst is added in an amount that makes the molar ratio of manganese dioxide to the reacted nitrile compound be between 0.05 and 1.5.

11. The process according to claim 10, wherein the catalyst is added in an amount that makes the molar ratio of manganese dioxide to the reacted nitrile compound be between 0.1 and 1.