阅读说明：本技术 一种对氰基苯甲酸的制备方法 (Preparation method of p-cyanobenzoic acid ) 是由 成家钢 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种对氰基苯甲酸的制备方法,步骤为：对甲基苯甲腈与溶剂、催化剂混合,向溶液中通入氧气,反应后精制得到对氰基苯甲酸。本发明还公开了对氰基苯甲酸反应母液再利用的方法：氧化反应结束后过滤,反应母液去除水分,重新加入等量的对甲基苯甲腈,并按比例补充冰醋酸,补加质量比0.5％-0.7％的催化剂,再重新进行氧化反应。本发明可以一步得到对氰基苯甲酸,反应简单,且成本低,收率高；通过对氰基苯甲酸的精制,可以能获得高纯度的成品,工艺简单；通过反应母液的循环利用,在降低成本的同时,进一步提升了产品的收率,降低了污染,实现清洁生产。(The invention discloses a preparation method of p-cyanobenzoic acid, which comprises the following steps: mixing the p-methylbenzonitrile with a solvent and a catalyst, introducing oxygen into the solution, and refining after reaction to obtain the p-cyanobenzoic acid. The invention also discloses a method for recycling the reaction mother liquor of p-cyanobenzoic acid, which comprises the following steps: filtering after the oxidation reaction is finished, removing water from reaction mother liquor, adding the same amount of p-methyl benzonitrile again, supplementing glacial acetic acid according to a proportion, supplementing a catalyst with the mass ratio of 0.5-0.7%, and then carrying out the oxidation reaction again. The method can obtain the p-cyanobenzoic acid in one step, and has the advantages of simple reaction, low cost and high yield; the high-purity finished product can be obtained by refining the p-cyanobenzoic acid, and the process is simple; by recycling the reaction mother liquor, the cost is reduced, the yield of the product is further improved, the pollution is reduced, and the clean production is realized.)

1. The preparation method of p-cyanobenzoic acid is characterized by comprising the following steps: mixing the p-methyl benzonitrile with a solvent and a catalyst, introducing oxygen into the solution for oxidation reaction, and then refining to obtain the p-cyanobenzoic acid.

2. The method for producing p-cyanobenzoic acid according to claim 1, characterized in that:

the catalyst is a mixture of cobalt acetate, manganese acetate and potassium bromide, and the mass ratio of the cobalt acetate to the manganese acetate to the potassium bromide is (1-3): (1-3): 1, the mass ratio of the p-methyl benzonitrile to the catalyst is (7-10): 1;

the solvent is glacial acetic acid, and the molar ratio of the p-methyl benzonitrile to the solvent is 1: (10-30);

the oxidation reaction temperature is 100-120 ℃;

the molar ratio of the p-methyl benzonitrile to the oxygen is 1: (2-3).

3. The method of claim 1, wherein the molar ratio of p-methylbenzonitrile to glacial acetic acid is 1: 24.5; the oxidation reaction temperature is 110 ℃, and the molar ratio of the p-methyl benzonitrile to the oxygen is 1: 2.25.

4. the method for producing p-cyanobenzoic acid according to claim 1, wherein the mass ratio of p-methylbenzonitrile to the catalyst is 7.8: 1; the catalyst is a mixture of cobalt acetate, manganese acetate and potassium bromide, and the mass ratio is 2:2: 1.

5. the method of claim 1, wherein when the mass fraction of p-methylbenzonitrile in the reaction solution is less than 0.5%, the introduction of oxygen is stopped and the temperature is reduced to 30 ℃.

6. The method for producing p-cyanobenzoic acid according to claim 1, wherein the refining process comprises: adding water into the crude product of the p-cyanobenzoic acid, heating, adjusting the pH value, decoloring, filtering, acidifying, filtering, washing with water and drying to obtain a refined p-cyanobenzoic acid product.

7. The method for preparing p-cyanobenzoic acid according to claim 6, wherein the temperature is raised to 70-90 ℃, the pH is adjusted by dropping alkali liquor until the pH is 7, and the decolorization is performed by adding activated carbon and stirring; the acidification was carried out at 75-85 ℃ with addition of acid solution to PH 3.8.

8. The method of claim 7, wherein the temperature of the elevated temperature is 80 ℃, the alkali solution is 30% sodium bicarbonate, and the acid solution is 10% dilute sulfuric acid.

9. The method for preparing p-cyanobenzoic acid according to claim 1, further comprising a method for recycling p-cyanobenzoic acid reaction mother liquor, comprising the steps of: after the oxidation reaction is finished and the reaction solution is filtered, removing water from the reaction mother solution, adding p-methyl benzonitrile again, supplementing glacial acetic acid and a catalyst, and then carrying out oxidation reaction by using oxygen.

10. The method for producing p-cyanobenzoic acid according to claim 9, characterized in that:

the step of removing water comprises the following steps: detecting the moisture in the mother liquor, and adding acetic anhydride according to a proportion until the moisture reacts;

the molar ratio of the glacial acetic acid to the p-methylbenzonitrile is 1: 23;

the mass of the catalyst accounts for 0.5-5% of that of the p-methyl benzonitrile; the catalyst is a mixture of cobalt acetate, manganese acetate and potassium bromide, and the molar ratio of the cobalt acetate to the manganese acetate to the potassium bromide in the catalyst is 2:2: 1;

the molar ratio of the p-cyanobenzoic acid to the oxygen is 1: 2.25.

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of p-cyanobenzoic acid.

[ background of the invention ]

The p-cyanobenzoic acid is an important intermediate of a highly selective blood coagulation factor Xa inhibitor betrazan, and the betrazan is used for preventing and treating acute venous thromboembolism of a patient with a high risk acute internal medicine. In view of the good application prospect of p-cyanobenzoic acid, the development of a preparation method of p-cyanobenzoic acid is urgent.

At present, the production methods of p-cyanobenzoic acid mainly comprise the following steps:

1. 4-chloromethyl benzonitrile is used as a raw material, and concentrated nitric acid is used as an oxidant to synthesize the p-cyanobenzoic acid, although the synthesis route is simple, the byproducts are too many, the pollution is serious, the three wastes are not easy to treat, and the synthesis method is not suitable for industrial application;

2. the p-cyanobenzoic acid is synthesized by taking the p-methanobenzoic acid as a raw material, but in the synthesis method, the formic acid is used, has strong corrosivity and is not suitable for working operation;

3. the method adopts an ammoxidation method to prepare the synthetic p-cyanobenzoic acid, but the method has the biggest problems that the reaction process needs very high pressure and temperature, the equipment requirement of industrial production can be increased, and the method is not suitable for industrial mass production.

In summary, the traditional synthesis method has the limitations of excessive by-products in the reaction process, strong corrosivity of the used reagent, high temperature and high pressure and the like, and thus the existing method can not meet the requirement of modern production of the cyanobenzoic acid.

At present, patent CN107556214A discloses a preparation method of p-cyanobenzoic acid, p-cyanobenzyl chloride is obtained by illumination chlorination of p-methylbenzonitrile, the p-cyanobenzyl chloride is hydrolyzed into p-cyanobenzyl alcohol by adding alkali, and the p-cyanobenzyl alcohol is oxidized into the p-cyanobenzoic acid by hydrogen peroxide.

[ summary of the invention ]

The invention aims to overcome the defects of the prior art and provide the preparation method of the p-cyanobenzoic acid, which has low cost, high yield and little pollution.

In order to achieve the purpose, the invention provides a preparation method of p-cyanobenzoic acid, which has the following principle:

specifically, the preparation method of the p-cyanobenzoic acid comprises the following steps:

under the catalysis of acetic acid solvent and cobalt-manganese-bromine system, introducing oxygen into the solution for reaction, and filtering and refining to obtain p-cyanobenzoic acid.

Further, the cobalt-manganese-bromine catalytic system is a mixture of cobalt acetate, manganese acetate and potassium bromide, and the mass ratio of the cobalt-manganese-bromine catalytic system to the manganese acetate to the potassium bromide is (1-3): (1-3): 1, preferably 2:2: 1;

further, the mass ratio of the p-methyl benzonitrile to the catalytic system mixture is (7-10): 1, preferably 7.8: 1;

further, the molar ratio of the p-methyl benzonitrile to the glacial acetic acid is 1: (10-30), preferably 1: 24.5;

further, the molar ratio of the p-methyl benzonitrile to the oxygen is 1: (2-3), preferably 1: 2.25;

further, the reaction temperature is 100-120 ℃, preferably 110 ℃.

Further, when the mass fraction of the p-methyl benzonitrile in the reaction is less than 0.5%, stopping introducing oxygen, cooling to 30 ℃, and filtering.

Further, the refining process after the reaction is finished comprises the following steps:

adding water into the crude product of the p-cyanobenzoic acid, heating, adding alkali liquor, adjusting the pH to be 7, decoloring, filtering, acidifying, filtering, washing with water and drying to obtain a refined p-cyanobenzoic acid product.

Further, the temperature rise is 70-90 ℃, preferably 80 ℃;

further, the alkali liquor is sodium bicarbonate water solution, preferably 30% sodium bicarbonate water solution;

further, the decolorization is activated carbon stirring decolorization;

further, acidifying at 75-85 ℃, and adding an acid solution until the pH is 3.8;

further, the acid solution is 10% dilute sulfuric acid.

Another object of the present invention is to provide a method for recycling reaction mother liquor, which specifically comprises:

and after the oxidation reaction is finished and the reaction solution is filtered, removing water from the reaction mother solution, adding the same amount of p-methyl benzonitrile again, supplementing glacial acetic acid according to a proportion, supplementing a catalyst, and then carrying out the oxidation reaction again.

Further, the mass of the supplemented catalyst accounts for 0.5-1% of the mass of the p-methyl benzonitrile;

further, the step of removing the water comprises the steps of detecting the water in the mother liquor and adding acetic anhydride according to the proportion until the water is completely reacted.

The invention has the beneficial effects that:

1. the p-cyanobenzene is used as a raw material, and oxygen is introduced for oxidation reaction under a cobalt-manganese-bromine catalytic system, so that the p-cyanobenzoic acid can be obtained in one step, the reaction is simple, the cost is low, and the yield is high;

2. the high-purity finished product can be obtained by refining the p-cyanobenzoic acid, and the process is simple;

3. by recycling the reaction mother liquor, the cost is reduced, the yield of the product is further improved, the pollution is reduced, and the clean production is realized.

[ detailed description ] embodiments

In order to make the objects, technical solutions and advantageous effects of the present invention more apparent, the present invention is further described in detail with reference to the following detailed description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.