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Method and production system for preparing p-cresol by catalytic hydrolysis of p-toluidine

A technology for catalytic hydrolysis of p-toluidine, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as complicated process, low quality and purity, high temperature and high pressure equipment, and achieve simple reaction process, Improve environmental benefits and ensure safe production

Inactive Publication Date: 2016-08-17
HUBEI KECY CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] However, the above methods generally have disadvantages such as complicated process, serious pollution, high temperature and high pressure, serious corrosion to equipment, difficult separation, and low quality and purity.

Method used

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  • Method and production system for preparing p-cresol by catalytic hydrolysis of p-toluidine

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Preparation of p-cresol by catalytic hydrolysis of p-toluidine

[0045]1) p-toluidine is hydrolyzed under catalyst and acidic conditions to obtain a hydrolyzed mixed solution.

[0046] 2) The hydrolyzed mixed solution obtained in step 1) is left to stand for stratification, and the organic phase is extracted and separated to obtain a crude p-cresol solution and a by-product 4,4'-dimethyldiphenylamine solution.

[0047] 3) The crude product p-cresol solution obtained in step 2) and the by-product 4,4'-dimethyldianiline solution are respectively rectified and dried successively to obtain the p-cresol product and 4,4'-dimethyldianiline crude product .

[0048] The pH value of hydrolysis is 5, provided by phosphoric acid, and the operating pressure of hydrolysis is 23kg / cm 2 , The hydrolysis operating temperature is 275°C, and the hydrolysis time is 12h.

[0049] The yield of p-cresol is 75.6%, and the purity is 99.85%.

Embodiment 2

[0051] Preparation of p-cresol by catalytic hydrolysis of p-toluidine

[0052] 1) p-toluidine is hydrolyzed under catalyst and acidic conditions to obtain a hydrolyzed mixed solution.

[0053] 2) The hydrolyzed mixed solution obtained in step 1) is left to stand for stratification, and the organic phase is extracted and separated to obtain a crude p-cresol solution and a by-product 4,4'-dimethyldiphenylamine solution.

[0054] 3) The crude product p-cresol solution obtained in step 2) and the by-product 4,4'-dimethyldianiline solution are respectively rectified and dried successively to obtain the p-cresol product and 4,4'-dimethyldianiline crude product .

[0055] The pH value of hydrolysis is 3, provided by sulfuric acid, and the operating pressure of hydrolysis is 32kg / cm 2 , The operating temperature of hydrolysis is 295°C, and the hydrolysis time is 10h.

[0056] The yield of p-cresol was 79.8%, and the purity was 99.75%.

Embodiment 3

[0058] Preparation of p-cresol by catalytic hydrolysis of p-toluidine

[0059] 1) p-toluidine is hydrolyzed under catalyst and acidic conditions to obtain a hydrolyzed mixed solution.

[0060] 2) The hydrolyzed mixed solution obtained in step 1) is left to stand for stratification, and the organic phase is extracted and separated to obtain a crude p-cresol solution and a by-product 4,4'-dimethyldiphenylamine solution.

[0061] 3) The crude product p-cresol solution obtained in step 2) and the by-product 4,4'-dimethyldianiline solution are respectively rectified and dried successively to obtain the p-cresol product and 4,4'-dimethyldianiline crude product .

[0062] The pH value of hydrolysis is 4, provided by phosphoric acid, and the operating pressure of hydrolysis is 26kg / cm 2 , the hydrolysis operating temperature is 287°C, and the hydrolysis time is 11h.

[0063] The yield of p-cresol was 77.1%, and the purity was 99.70%.

[0064] Through the method and system provided...

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Abstract

The invention belongs to the technical field of chemical synthesis, and in particular relates to a method and a production system for preparing p-cresol by catalytic hydrolysis of p-toluidine. The method comprises the steps of: 1) hydrolyzing p-toluidine under a catalyst and an acidic condition to obtain a mixed solution after hydrolysis; 2) leaving the mixed solution after hydrolysis obtained in step 1) to stand for stratification, and the organic phase is subjected to extraction and After separation, crude product p-cresol solution and by-product 4,4'-dimethyldiphenylamine solution are obtained. The system includes a hydrolysis reactor, a filter connected in series with the hydrolysis reactor, a layerer connected in series with the filter, an extraction column connected in series with the layerer, and a first rectification column and a second rectification column connected in series with the extraction column respectively. , the first distillation column is connected with a first vacuum dryer, and the second distillation column is connected with a second vacuum dryer. Through the method and system provided by the present invention, high-purity p-cresol can be prepared, and 4,4'-dimethyldiphenylamine crude product can be co-produced at the same time.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method and a production system for preparing p-cresol by catalytically hydrolyzing p-toluidine. Background technique [0002] At present, the commonly used methods for synthesizing p-cresol in the chemical industry include: natural separation method, toluene sulfonation alkali fusion method, phenol alkylation method, cumene method, etc. [0003] (1) The natural separation method is the traditional preparation method of cresol, and p-cresol can be obtained by fractional distillation from coal tar. However, because of limited resources, coupled with a complex process, and the need for many separation devices, natural separation technology has been facing the point of elimination. [0004] (2) The toluene sulfonation alkali fusion method is the main method for producing p-cresol in China at present. The advantage of this method is that the technology is ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/05C07C37/70C07C37/74C07C39/07
CPCC07C37/05C07C37/70C07C37/74
Inventor 蔡春杨春赵瑞先
Owner HUBEI KECY CHEM
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