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Preparation method of p-hydroxybenzoic acid

A p-hydroxybenzoic acid and phenol technology, applied in the field of chemical technology, can solve problems such as high equipment requirements, long process flow, and difficult production, and achieve the effects of avoiding safety and environmental hazards, easy operation of the reaction, and low environmental pollution

Pending Publication Date: 2021-11-26
宿迁思睿屹新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. The most common industrial process for producing hydroxybenzoic acid is the Kolbe-Schmitt carboxylation of phenol. However, this method has a serious disadvantage that it needs to prepare dry potassium phenate in advance. Due to the need to carry out vacuum distillation to remove water, but drying The extreme hygroscopicity of potassium phenate makes it difficult to prepare dry potassium phenate;
[0005] 2. The domestic mainstream uses salicylic acid as a raw material. After converting it into potassium salt with potassium hydroxide, it is transposed at high temperature in the presence of potassium carbonate and acidified to produce p-hydroxybenzoic acid. Although the process is mature, it needs to pass Carboxylation reaction to synthesize salicylic acid, and then transposition into p-hydroxybenzoic acid, is an indirect synthesis method with long process and high cost;
[0006] 3. Using potassium phenate or sodium phenate as raw material, with potassium carbonate or sodium in the presence of formate, under high pressure and high temperature, carry out carboxylation reaction with carbon monoxide to obtain p-hydroxybenzoic acid, although the yield of this method is high , but the required pressure is high, the requirements for equipment are high, and carbon monoxide gas needs to be continuously generated, so the production is difficult

Method used

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  • Preparation method of p-hydroxybenzoic acid

Examples

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Effect test

Embodiment 1

[0024] A preparation method of p-hydroxybenzoic acid, the steps are as follows:

[0025] S1. Synthesis of potassium methoxide and potassium monomethyl carbonate: put methanol and potassium hydroxide in a reaction vessel, heat to 90°C, and remove the generated water continuously during the reaction until the content of potassium hydroxide and water in the reaction mixture is reached Qualified, you can get potassium methylate; potassium methylate in 0.9atm CO 2 Reaction under atmosphere for 23h, can obtain monomethyl carbonate potassium salt;

[0026] S2, p-hydroxybenzoic acid synthesis:

[0027] 9.4 g (0.1 mol) of phenol and 12.6 g (0.1 mol) of potassium monomethyl carbonate were placed in a glass reactor in a 100 mL stainless steel autoclave. The autoclave was sealed and the required pressure was created with air, stirring and heating started. The gas pressure was kept constant during the reaction. The temperature of the reactor was raised to 210°C, and the reaction was ca...

Embodiment 2

[0029] A preparation method of p-hydroxybenzoic acid, the steps are as follows:

[0030] S1. Synthesis of potassium methoxide and monomethyl carbonate potassium salt: put methanol and potassium hydroxide in a reaction vessel, heat to 95°C, and continuously remove the generated water during the reaction until the content of potassium hydroxide and water in the reaction mixture is reached Qualified, you can get potassium methylate; potassium methylate in 0.9atm CO 2 React under atmosphere for 23.5h to get monomethyl carbonate potassium salt;

[0031] S2. Synthesis of p-hydroxybenzoic acid: 9.4 g (0.1 mol) of phenol and 12.6 g (0.1 mol) of potassium monomethyl carbonate were placed in a glass reactor in a 100 mL stainless steel autoclave. The autoclave was sealed and the required pressure was created with argon, stirring and heating started. The gas pressure was kept constant during the reaction. The temperature of the reactor was raised to 210°C, and the reaction was carried ...

Embodiment 3

[0033] A preparation method of p-hydroxybenzoic acid, the steps are as follows:

[0034] S1. Synthesis of potassium methoxide and monomethyl carbonate potassium salt: put methanol and potassium hydroxide in a reaction vessel, heat to 98°C, and continuously remove the generated water during the reaction until the content of potassium hydroxide and water in the reaction mixture is reached Qualified, you can get potassium methoxide; potassium methoxide in 1atm CO 2 Reaction under atmosphere for 23h, can obtain monomethyl carbonate potassium salt;

[0035] S2. Synthesis of p-hydroxybenzoic acid: 9.4 g (0.1 mol) of phenol and 12.6 g (0.1 mol) of potassium monomethyl carbonate were placed in a glass reactor in a 100 mL stainless steel autoclave. The autoclave was sealed and the required pressure was created with carbon dioxide, stirring and heating started. The gas pressure was kept constant during the reaction. The temperature of the reactor was raised to 210°C, and the reaction...

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Abstract

The invention provides a preparation method of p-hydroxybenzoic acid, and particularly relates to the field of chemical processes, wherein the preparation method comprises the following steps: S1, firstly preparing potassium methoxide by using methanol and potassium hydroxide as raw materials, and then reacting the potassium methoxide with carbon dioxide to generate potassium monomethyl carbonate; s2, reacting the potassium monomethyl carbonate with phenol to prepare the target product p-hydroxybenzoic acid. The method has the advantages of high yield, easy reaction operation, simple post-treatment and small environmental pollution.

Description

technical field [0001] The invention belongs to the field of chemical technology, and in particular relates to a preparation method of p-hydroxybenzoic acid. Background technique [0002] P-hydroxybenzoic acid is a widely used raw material for organic synthesis, especially its esters. P-hydroxybenzoic acid is also used as an intermediate for dyes and pesticides. It is used in the synthesis of organophosphorus insecticides GYAP and CYP in pesticides; it is used in the dye industry to synthesize heat-sensitive dyes; it can also be used in color film and synthetic oil-soluble coupler "538" and nylon 12. Raw materials for the production of plasticizers. In addition, it is also used in liquid crystal polymers and plastics. For preservatives, fungicides. Pharmacological experiments show that it has obvious protective effect on cobra poisoning in mice; [0003] Synthetic p-hydroxybenzoic acid mainly discloses following several methods at present: [0004] 1. The most common i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/00C07C65/03
CPCC07C51/00C07C68/04C07C65/03C07C69/96
Inventor 柯友斌何珉刘雷张小雷
Owner 宿迁思睿屹新材料股份有限公司
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