Preparation method of high-purity 2, 2-dimethyl butyric acid

Abstract

The invention relates to the technical field of organic synthesis, and provides a preparation method of high-purity 2, 2-dimethyl butyric acid, which comprises the following steps: by taking isoamylene as a raw material, adding water and carbon monoxide, carrying out carbonylation reaction under the action of a catalyst, and hydrolyzing to obtain 2, 2-dimethyl butyric acid, the catalyst comprises a supported solid catalyst and a liquid catalyst; the supported solid catalyst comprises a carrier and an active component; the carrier is diatomite; the active component is organic sulfonic acid; the liquid catalyst comprises one or two of concentrated sulfuric acid and phosphoric acid; the mass ratio of the supported solid catalyst to the liquid catalyst is (1: 1)-(1: 9). According to the technical scheme, the problem of low yield of 2, 2-dimethylbutyric acid in related technologies is solved.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for preparing high-purity 2,2-dimethylbutyric acid. Background Art

[0002] 2,2-dimethylbutyric acid is an important organic compound that plays a key role in many industries. In the pharmaceutical field, 2,2-dimethylbutyric acid is an important intermediate of the lipid-lowering drug simvastatin. Simvastatin was developed by Merck in the United States. It is a HMG-CoA reductase inhibitor semi-synthesized from lovastatin as a raw material. It is a drug for the treatment of primary hypercholesterolemia. It can effectively prevent the development of atherosclerosis and the recurrence of heart disease, and reduce the risk of non-fatal myocardial infarction and myocardial revascularization. In the field of pesticides, 2,2-dimethylbutyric acid is a key intermediate for the preparation of spirodiclofen, which belongs to the spirocyclic tetraketone insecticide and has a good effect on the prevention and control of whiteflies and spider mites. 2,2-dimethylbutyric acid has always been mainly prepared by the reaction of isopentanol and formic acid under the catalysis of sulfuric acid. The yield of 2,2-dimethylbutyric acid prepared by this method is low, which increases the production cost. Therefore, the development of a high-yield and high-purity preparation method for 2,2-dimethylbutyric acid is a problem that needs to be solved at present. Summary of the invention

[0003] The invention provides a method for preparing high-purity 2,2-dimethylbutyric acid, which solves the problem of low yield of 2,2-dimethylbutyric acid in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a method for preparing high-purity 2,2-dimethylbutyric acid, comprising the following steps: Using isopentene as raw material, adding water and carbon monoxide, a carbonylation reaction is carried out under the action of a catalyst, and then 2,2-dimethylbutyric acid is obtained by hydrolysis; The catalyst comprises a supported solid catalyst and a liquid catalyst; the supported solid catalyst comprises a carrier and an active component; the carrier is diatomaceous earth; the active component is an organic sulfonic acid; the liquid catalyst comprises one or two of concentrated sulfuric acid and phosphoric acid; the mass ratio of the supported solid catalyst to the liquid catalyst is 1:1 to 1:9.

[0005] As a further technical solution, the mass ratio of the supported catalyst to the liquid catalyst is 1-4:6.

[0006] As a further technical solution, the organic sulfonic acid includes one or more of hydroxylamine sulfonic acid, isophthalic acid, and 1,2-ethanedisulfonic acid.

[0007] As a further technical solution, the organic sulfonic acid is hydroxylamine sulfonic acid and 1,2-ethanedisulfonic acid; the mass ratio of the hydroxylamine sulfonic acid to the 1,2-ethanedisulfonic acid is 1:4-8.

[0008] In the present invention, the yield of 2,2-dimethylbutyric acid is further improved by limiting the organic sulfonic acid to consist of hydroxylamine sulfonic acid and 1,2-ethanedisulfonic acid, and limiting the mass ratio of hydroxylamine sulfonic acid to 1,2-ethanedisulfonic acid to 1:4-8.

[0009] As a further technical solution, the mass ratio of the organic sulfonic acid to the diatomaceous earth is 1-2:5.

[0010] As a further technical solution, the preparation method of the supported solid catalyst comprises the following steps: dissolving organic sulfonic acid in ethanol, adding diatomaceous earth for impregnation, and obtaining the supported solid catalyst after drying.

[0011] As a further technical solution, the immersion time is 2 to 4 hours.

[0012] As a further technical solution, the mass ratio of the catalyst to the isopentene is 3-8:10; the mass ratio of the water to the isopentene is 1-2:10.

[0013] As a further technical solution, the temperature of the carbonylation reaction is 30-40° C., and the time of the carbonylation reaction is 5-7 hours.

[0014] As a further technical solution, at least one of the following features is included: The pressure of the carbonylation reaction is 5-6 MPa; The temperature of the hydrolysis reaction is 5-10°C, and the time of the hydrolysis reaction is 2-3h; The purification of 2,2-dimethylbutyric acid includes extraction and distillation.

[0015] As a further technical solution, the extraction solvent is dichloromethane; and the distillation method is vacuum distillation.

[0016] The working principle and beneficial effects of the present invention are: In the present invention, isopentene is used as a raw material, and carbon monoxide and water are reacted with a catalyst to obtain 2,2-dimethylbutyric acid through carbonylation reaction and hydrolysis. The catalyst includes a supported solid catalyst and a liquid catalyst, which improves the carbonylation reaction efficiency and further improves the yield of 2,2-dimethylbutyric acid. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the following examples and comparative examples, Diatomaceous earth, particle size: 500 mesh.

[0019] Example 1 A method for preparing high-purity 2,2-dimethylbutyric acid comprises the following steps: 70 g of water, 189 g of concentrated sulfuric acid (98 wt%) and 21 g of a supported solid catalyst were added to the reactor, carbon monoxide gas was introduced until the pressure reached 5 MPa, 700 g of isopentene was added to the reactor, the temperature was raised to 30°C, and the reaction was continued for 7 h. The reaction solution was then added to ice water for hydrolysis. After hydrolysis at 5°C for 2 h, dichloromethane was added for extraction, and the organic phase was distilled under reduced pressure to obtain 1050.4 g of 2,2-dimethylbutyric acid. GC analysis showed that the purity of 2,2-dimethylbutyric acid was 99.5%, and the yield was 90.1%.

[0020] The preparation method of a supported solid catalyst comprises the following steps: dissolving 9 g of hydroxylamine sulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 4 hours, and obtaining the supported solid catalyst after drying.

[0021] Example 2 A method for preparing high-purity 2,2-dimethylbutyric acid comprises the following steps: 140 g of water, 280 g of phosphoric acid (85 wt %) and 280 g of a supported solid catalyst were added to the reactor, carbon monoxide gas was introduced until the pressure reached 6 MPa, 700 g of isopentene was added to the reactor, the temperature was raised to 40°C, and after reacting for 5 h, the reaction solution was added to ice water for hydrolysis. After hydrolysis at 10°C for 3 h, dichloromethane was added for extraction, and the organic phase was distilled under reduced pressure to obtain 1058.6 g of 2,2-dimethylbutyric acid. GC analysis showed that the purity of 2,2-dimethylbutyric acid was 99.5%, and the yield was 90.8%.

[0022] The preparation method of a supported solid catalyst comprises the following steps: dissolving 18 g of hydroxylamine sulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 2 hours, and obtaining the supported solid catalyst after drying.

[0023] Example 3 The only difference between this embodiment and embodiment 1 is that the amount of concentrated sulfuric acid (98 wt %) added is 180 g, and the amount of supported solid catalyst added is 30 g.

[0024] Result: 1079.6 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.5% by GC analysis, and the yield was 92.6%.

[0025] Example 4 The only difference between this embodiment and embodiment 1 is that the amount of concentrated sulfuric acid (98 wt %) added is 126 g, and the amount of supported solid catalyst added is 84 g.

[0026] Result: 1073.8 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.6% after GC analysis, and the yield was 92.2%.

[0027] Example 5 The only difference between this embodiment and embodiment 3 is that in the preparation method of the supported solid catalyst, hydroxylamine sulfonic acid is replaced by an equal amount of 1,2-ethanedisulfonic acid.

[0028] Result: 1089.0 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.6% after GC analysis, and the yield was 93.5%.

[0029] Example 6 The only difference between this embodiment and embodiment 3 is that the preparation method of the supported solid catalyst comprises the following steps: dissolving 4.5 g of hydroxylamine sulfonic acid and 4.5 g of 1,2-ethanedisulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 4 h, and obtaining the supported solid catalyst after drying.

[0030] Result: 1093.6 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.6% after GC analysis, and the yield was 93.9%.

[0031] Example 7 The only difference between this embodiment and embodiment 3 is that the preparation method of the supported solid catalyst includes the following steps: dissolving 0.75 g of hydroxylamine sulfonic acid and 8.25 g of 1,2-ethanedisulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 4 hours, and obtaining the supported solid catalyst after drying.

[0032] Result: 1099.4 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.6% after GC analysis, and the yield was 94.4%.

[0033] Example 8 The only difference between this embodiment and embodiment 3 is that the preparation method of the supported solid catalyst includes the following steps: dissolving 1.8 g of hydroxylamine sulfonic acid and 7.2 g of 1,2-ethanedisulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 4 hours, and obtaining the supported solid catalyst after drying.

[0034] Results: 1113.5 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.7% after GC analysis, and the yield was 95.7%.

[0035] Example 9 The only difference between this embodiment and embodiment 3 is that the preparation method of the supported solid catalyst includes the following steps: dissolving 1 g of hydroxylamine sulfonic acid and 8 g of 1,2-ethanedisulfonic acid in 100 mL of ethanol, adding 45 g of diatomaceous earth and soaking for 4 h, and obtaining the supported solid catalyst after drying.

[0036] Results: 1113.5 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.7% after GC analysis, and the yield was 95.7%.

[0037] Comparative Example 1 The only difference between this comparative example and Example 1 is that the supported solid catalyst is replaced by an equal amount of concentrated sulfuric acid (98 wt %).

[0038] Results: 1020.7 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.1% after GC analysis, and the yield was 87.2%.

[0039] Comparative Example 2 The only difference between this comparative example and Example 1 is that concentrated sulfuric acid (98 wt %) is replaced by an equal amount of supported solid catalyst.

[0040] Result: 996.5 g of 2,2-dimethylbutyric acid was obtained. The purity of 2,2-dimethylbutyric acid was 99.3% after GC analysis, and the yield was 85.3%.

[0041] Compared with Comparative Example 1 in which the catalyst is only concentrated sulfuric acid and Comparative Example 2 in which the catalyst is only a supported solid catalyst, the catalyst in Example 1 consists of concentrated sulfuric acid and a supported solid catalyst. As a result, the yield and purity of 2,2-dimethylbutyric acid prepared in Example 1 are higher than those in Comparative Examples 1 and 2, indicating that when the catalyst consists of concentrated sulfuric acid and a supported solid catalyst, the yield and purity of 2,2-dimethylbutyric acid can be improved.

[0042] Compared with Example 1, the mass ratio of concentrated sulfuric acid to the supported solid catalyst was changed in Examples 3 to 4. As a result, the yield of 2,2-dimethylbutyric acid obtained in Examples 3 to 4 was higher than that in Example 1, indicating that when the mass ratio of concentrated sulfuric acid to the supported solid catalyst was 1 to 4:6, the yield of 2,2-dimethylbutyric acid could be further improved.

[0043] Compared with Example 3, the active components of the supported solid catalyst in Example 5 are 1,2-ethanedisulfonic acid, and the active components of the supported solid catalyst in Example 6 are 1,2-ethanedisulfonic acid and hydroxylaminesulfonic acid. As a result, the yield of 2,2-dimethylbutyric acid prepared in Example 6 is higher than that in Example 3 and Example 5, indicating that when the active components of the supported solid catalyst are 1,2-ethanedisulfonic acid and hydroxylaminesulfonic acid, the yield of 2,2-dimethylbutyric acid can be further improved.

[0044] Compared with Example 6, Examples 7 to 9 changed the mass ratio of 1,2-ethanedisulfonic acid and hydroxylaminesulfonic acid. As a result, the yield of 2,2-dimethylbutyric acid obtained in Examples 8 to 9 was higher than that in Examples 6 and 7, indicating that when the mass ratio of 1,2-ethanedisulfonic acid and hydroxylaminesulfonic acid was 4 to 8:1, the yield of 2,2-dimethylbutyric acid could be further improved.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing high-purity 2,2-dimethylbutyric acid, characterized in that: The following steps are involved: Using isopentene as raw material, adding water and carbon monoxide, a carbonylation reaction is carried out under the action of a catalyst, and then 2,2-dimethylbutyric acid is obtained by hydrolysis; The catalyst comprises a supported solid catalyst and a liquid catalyst; the supported solid catalyst comprises a carrier and an active component; the carrier is diatomaceous earth; the active component is an organic sulfonic acid; the liquid catalyst comprises one or two of concentrated sulfuric acid and phosphoric acid; the mass ratio of the supported solid catalyst to the liquid catalyst is 1:1 to 1:

9.

2. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The mass ratio of the supported catalyst to the liquid catalyst is 1-4:

6.

3. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The organic sulfonic acid includes one or more of hydroxylamine sulfonic acid, isophenyl disulfonic acid, and 1,2-ethanedisulfonic acid.

4. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 3, characterized in that: The organic sulfonic acid is hydroxylamine sulfonic acid and 1,2-ethanedisulfonic acid; the mass ratio of the hydroxylamine sulfonic acid to the 1,2-ethanedisulfonic acid is 1:4-8.

5. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The mass ratio of the organic sulfonic acid to the diatomaceous earth is 1-2:

5.

6. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The preparation method of the supported solid catalyst comprises the following steps: dissolving organic sulfonic acid in ethanol, adding diatomaceous earth for impregnation, and obtaining the supported solid catalyst after drying.

7. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 6, characterized in that: The immersion time is 2 to 4 hours.

8. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The mass ratio of the catalyst to the isopentene is 3-8:10; the mass ratio of the water to the isopentene is 1-2:

10.

9. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: The temperature of the carbonylation reaction is 30-40° C., and the time of the carbonylation reaction is 5-7 hours.

10. The method for preparing high-purity 2,2-dimethylbutyric acid according to claim 1, characterized in that: Also includes at least one of the following features: The pressure of the carbonylation reaction is 5-6 MPa; The temperature of the hydrolysis reaction is 5-10°C, and the time of the hydrolysis reaction is 2-3h; The purification of 2,2-dimethylbutyric acid includes extraction and distillation.