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Preparation method of p-cyanobenzoic acid

A technology of cyanobenzoic acid and methylbenzonitrile, which is applied in the preparation of carboxylic acid nitriles, the preparation of organic compounds, chemical instruments and methods, etc., can solve the problems of increasing industrial production equipment requirements, pollution, unsuitable work operations, etc. Achieve the effect of realizing clean production, reducing pollution and improving yield

Inactive Publication Date: 2020-08-25
成家钢
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. Using 4-chloromethylbenzonitrile as a raw material and concentrated nitric acid as an oxidant to synthesize p-cyanobenzoic acid. Although the synthetic route is simple, there are too many by-products, serious pollution, and difficult disposal of three wastes, which is not suitable for industrial applications;
[0005] 2. Synthesize p-cyanobenzoic acid with p-methanol benzoic acid as raw material, but in this synthesis method, formic acid is used, which is highly corrosive and not suitable for working operations;
[0006] 3. The ammoxidation method is used to prepare synthetic p-cyanobenzoic acid, but the biggest problem with this method is that high pressure and temperature are required in the reaction process, which will increase the equipment requirements for industrial production, and is not suitable for large-scale industrial production
[0007] In summary, the traditional synthetic method has too many by-products in the reaction process, the use of reagents is highly corrosive, and high temperature and high pressure are limiting conditions. It can be seen that the existing method cannot meet the needs of modern production of p-cyanobenzoic acid.
[0008] At present, the patent CN107556214A discloses the preparation method of p-cyanobenzoic acid, obtains p-cyanobenzyl chloride by light chlorination of p-methylbenzonitrile, and hydrolyzes p-cyanobenzyl chloride with alkali to form p-cyanobenzyl alcohol. Cyanobenzyl alcohol is oxidized into p-cyanobenzoic acid with hydrogen peroxide. This method has long reaction steps, low yield, high cost and serious pollution. Under the situation that the current environmental protection situation is more and more strict, this method cannot be produced normally. Therefore develop a kind of cost low, and yield is high, the preparation method of the new p-cyanobenzoic acid that pollutes little appears particularly important

Method used

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  • Preparation method of p-cyanobenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Oxidation: Put 117kg of p-toluonitrile, 6kg of cobalt acetate, 6kg of manganese acetate, 3kg of potassium bromide, and 1500kg of glacial acetic acid (98%) into a 2000L glass-lined reactor with condenser, oxygen pipe and tail gas absorption device , start stirring and heat up to 110°C, and feed 72kg of oxygen at a uniform speed; take the reaction solution to control, when the mass fraction of p-toluonitrile is less than 0.5%, stop the oxygen and cool down to 30°C, and dry to obtain p-cyanobenzoic acid The wet weight of the crude product is 190kg.

[0038] Refining: Add 190kg of crude p-cyanobenzoic acid and 2000L of water to a 3000L glass-lined reactor, raise the temperature to 80°C, add 30% aqueous sodium bicarbonate dropwise to adjust the pH to 7, add 3kg of activated carbon and stir for 30 minutes to decolorize, filter into another In a 3000L glass-lined reactor, raise the temperature to 80°C, add 10% dilute sulfuric acid dropwise at 75-85°C to adjust the pH to 3.8, s...

Embodiment 2

[0041] Oxidation: Put 117kg p-tolunitrile, 5kg cobalt acetate, 5kg manganese acetate, 5kg potassium bromide, 1835kg glacial acetic acid (98%) into a 2000L glass-lined reactor with condenser, oxygen pipe and tail gas absorption device , start stirring and heat up to 120°C, and feed 96kg of oxygen at a constant speed; take the reaction solution to control, when the mass fraction of p-toluonitrile is less than 0.5%, stop the oxygen and cool down to 30°C, and dry to obtain the crude product of p-cyanobenzoic acid Wet weight 185kg.

[0042] Refining: Add 185kg of crude p-cyanobenzoic acid and 2000L of water to a 3000L glass-lined reactor, raise the temperature to 90°C, add 30% aqueous sodium bicarbonate dropwise to adjust the pH to 7, add 3kg of activated carbon and stir for decolorization for 30 minutes, filter into another In a 3000L glass-lined reactor, raise the temperature to 80°C, add 10% dilute sulfuric acid dropwise at 75-85°C to adjust the pH to 3.8, spin dry, wash with wa...

Embodiment 3

[0044] Oxidation: drop into 117kg p-methylbenzonitrile, 7.2kg cobalt acetate, 7.2kg manganese acetate, 2.4kg potassium bromide, 612kg glacial acetic acid ( 98%), start stirring and heat up to 100°C, and feed 64kg of oxygen at a constant speed; take the reaction solution to control, when the mass fraction of p-toluyl nitrile is less than 0.5%, stop the oxygen and cool down to 30°C, and dry to obtain p-cyano Benzoic acid crude product wet weight 181kg.

[0045] Refining: Add 181kg of crude p-cyanobenzoic acid and 2000L of water to a 3000L glass-lined reactor, raise the temperature to 70°C, add 30% aqueous sodium bicarbonate dropwise to adjust the pH to 7, add 3kg of activated carbon and stir for 30 minutes to decolorize, filter into another In a 3000L glass-lined reactor, raise the temperature to 80°C, add 10% dilute sulfuric acid dropwise at 75-85°C to adjust the pH to 3.8, spin dry, wash with water, spin dry, and dry to obtain 138.6kg of p-cyanobenzoic acid finished product. ...

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Abstract

The invention discloses a preparation method of p-cyanobenzoic acid, which comprises the following steps: mixing p-tolunitrile with a solvent and a catalyst, introducing oxygen into the solution for reaction, and refining to obtain p-cyanobenzoic acid. The invention also discloses a method for recycling p-cyanobenzoic acid reaction mother liquor, which comprises the following steps: filtering after the oxidation reaction is finished, removing water from the reaction mother liquor, adding the same amount of p-tolunitrile again, supplementing glacial acetic acid in proportion, supplementing 0.5-0.7 wt% of a catalyst, and carrying out oxidation reaction again. According to the method, p-cyanobenzoic acid can be obtained in one step, the reaction is simple, the cost is low, and the yield is high; through refining of p-cyanobenzoic acid, a high-purity finished product can be obtained, and the process is simple; and through cyclic utilization of the reaction mother liquor, the cost is reduced, the yield of the product is further improved, the pollution is reduced, and clean production is realized.

Description

【Technical field】 [0001] The invention relates to the technical field of chemical synthesis, in particular to a preparation method of p-cyanobenzoic acid. 【Background technique】 [0002] p-Cyanobenzoic acid is an important intermediate of betriraban, a highly selective coagulation factor Xa inhibitor. Betriraban is used for the prevention and treatment of acute venous thromboembolism in patients with high-risk acute medical diseases. Currently, it is used in China, the United States, The UK and other countries conduct phase III clinical trials and phase II clinical trials for the prevention and treatment of pulmonary embolism. In view of the fact that p-cyanobenzoic acid has such a good application prospect, it is urgent to develop a preparation method for p-cyanobenzoic acid. [0003] At present, the production methods of p-cyanobenzoic acid mainly contain the following types: [0004] 1. Using 4-chloromethylbenzonitrile as a raw material and concentrated nitric acid as a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C253/30C07C255/57C07C253/34
CPCC07C253/30C07C253/34C07C255/57
Inventor 成家钢
Owner 成家钢