Method for preparing p-toluenesulfonic acid by toluene sulfonation

A p-toluenesulfonic acid and toluene technology, applied in the preparation of sulfonic acid, organic chemistry, etc., can solve the problems of many by-products, difficulty in ensuring purity, excessive acid residue, etc., and achieve short process, convenient operation, and high content of finished products Effect

Active Publication Date: 2010-09-29
SUZHOU XINGYE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method for preparing p-toluenesulfonic acid, which solves the problems of producing more by-products, too much acid residue, difficulty in guaranteeing purity, etc. in the preparation of p-toluenesulfonic acid in the prior art

Method used

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  • Method for preparing p-toluenesulfonic acid by toluene sulfonation

Examples

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Effect test

Embodiment 1

[0019] Example 1 Process for preparing p-toluenesulfonic acid according to the present invention

[0020]

[0021] Add 250g of toluene to a four-necked flask with stirring, reflux, water separator and thermometer, heat up to increase the temperature, add 100g of concentrated sulfuric acid (98%) dropwise under the toluene reflux condition, add dropwise evenly within 30min, continue to reflux and heat, The water generated by the reaction and the water in the concentrated sulfuric acid are taken out with toluene vapor, the toluene is condensed and refluxed, and when water is no longer separated in the reflux liquid, the reaction is completed for 4 hours. Cool down and add 20 g of compounding agent (a mixture of water and alcohol) at a temperature of 50-70 °C to precipitate a crystalline compound, then carry out vacuum filtration and vacuum drying at 70 °C to obtain the product.

[0022] It was determined that the content of the finished product was 98.7%, the purity of p-tolue...

Embodiment 2

[0023] Example 2 The process for preparing p-toluenesulfonic acid according to the present invention and the comparison with the existing process

[0024]

[0025] Add 280g of toluene to a four-necked flask with stirring, reflux, water separator, and thermometer, heat up the temperature, add 110g of concentrated sulfuric acid (98%) dropwise under the condition of toluene reflux, add dropwise evenly within 30min, continue to reflux and heat, The water generated by the reaction and the water in the concentrated sulfuric acid are taken out with toluene vapor, the toluene is condensed and refluxed, and when no water is separated from the reflux liquid, the reaction is continued for 1 hour to complete the reaction. Cool the temperature and add 15 g of compounding agent (a mixture of water and alcohol) at a temperature of 50-70 °C to separate out a crystalline compound, then carry out vacuum filtration and vacuum drying at 70 °C to obtain the product.

[0026] After the sulfonati...

Embodiment 3

[0030] Example 3 Process for preparing p-toluenesulfonic acid according to the present invention

[0031]

[0032] Add 260 g of toluene to a four-necked flask with stirring, reflux, water separator and thermometer, heat up to increase the temperature, add 120 g of concentrated sulfuric acid (98%) dropwise under the condition of toluene reflux, add dropwise evenly within 30 min, and continue to reflux for heating. The water generated by the reaction and the water in the concentrated sulfuric acid were taken out with toluene vapor, the toluene was condensed and refluxed, and when no water was separated from the reflux liquid, the reaction was completed for 5 hours. Cool down and add 20 g of compounding agent (a mixture of water and alcohol) at a temperature of 50-70 °C to precipitate a crystalline compound, then carry out vacuum filtration and vacuum drying at 70 °C to obtain the product.

[0033] It was determined that the content of the finished product was 98.9%, the purit...

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Abstract

The invention discloses a method for preparing p-toluenesulfonic acid by toluene sulfonation, which is characterized by comprising a step of adding a compound agent into a reaction product to perform crystallization after toluene and sulfonating agent produce sulfonation reaction, wherein the compound agent consists of at least two different p-toluenesulfonic acid solvents. A p-toluenesulfonic acid finished product prepared by the method has high content and has high purity of the p-toluenesulfonic acid; and the finished product content is more than or equal to 98.5 percent and the purity of the p-toluenesulfonic acid is more than or equal to 99.5 percent through detection, and the finished product is difficult to form blocks after placing. Because the synthesis and refining are finished in the same reaction system, the method has the advantages of short flow, convenient operation, improved production efficiency and reduced labor intensity.

Description

technical field [0001] The invention belongs to the technical field of fine chemical raw material synthesis, in particular to a method for preparing p-toluenesulfonic acid by toluene sulfonation. Background technique [0002] P-toluenesulfonic acid is a very important organic chemical intermediate, and p-toluenesulfonic acid is a commonly used acid catalyst in organic synthesis. It can be neutralized with sodium hydroxide to obtain sodium p-toluenesulfonate, and then reacted with phosphorus pentachloride to obtain p-toluenesulfonyl chloride. p-Toluenesulfonyl chloride is used in nucleophilic substitution reactions and is also used as a protecting group for alcoholic hydroxyl groups. The use of p-toluenesulfonic acid also includes: catalyzing dihydrofuran protecting groups on alcohols; esterification of carboxylic acids; transesterification; making aldehydes into acetals, etc. It is widely used in various chemical reactions. Because of its stable chemical properties, it is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C309/30C07C303/08C07C303/06
Inventor 王进兴王文浩朱文英
Owner SUZHOU XINGYE CHEM
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