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Method for preparing para toluene sulfonamide by directly amidating para-toluenesulfonic acid

A technology of p-toluenesulfonamide and p-toluenesulfonic acid is applied in the field of preparing p-toluenesulfonamide by catalytic sulfonamide reaction, and can solve the problems of environmental pollution, a large amount of waste acid and the like

Active Publication Date: 2015-09-30
浙江嘉福新材料科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although it has realized the up-to-standard discharge of ammonia in the tail gas and reduced environmental pollution, the raw material p-toluenesulfonyl chloride in this method is obtained after the reaction of p-toluenesulfonic acid and chlorosulfonic acid, and this reaction will produce a large amount of waste acid, seriously pollutes the environment and is restricted by environmental protection. Therefore, it is of great significance to find a new catalytic method to prepare p-toluenesulfonamide

Method used

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  • Method for preparing para toluene sulfonamide by directly amidating para-toluenesulfonic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1. Dissolve 3.444g (20mmol) of anhydrous p-toluenesulfonic acid and 0.172g of 2-bromophenylboronic acid in dichloromethane, add 5g of molecular sieve type 5A, and stir evenly at 0°C for 2h.

[0018] 2. Heat 20g of 25% ammonia water, and the generated ammonia gas is passed into the reaction solution after passing through the gas drying processor. Add 20g of ammonia water every 4h until 24h, adding 120g of ammonia water in total.

[0019] 3. After the molecular sieves were removed by suction filtration, the filtrate was washed once with 10 mL hydrochloric acid solution (0.5 mol / L concentration), 10 mL sodium hydroxide solution (0.5 mol / L concentration) and 10 mL saturated NaCl solution.

[0020] 4. After the organic phase was dried with anhydrous sodium sulfate, the desiccant was removed, and dichloromethane was recovered by distillation to obtain a crude product of p-toluenesulfonamide, which was washed with distilled water and dried to obtain a white crystal weighing 1....

Embodiment 2

[0023] 1. Dissolve 3.444g (20mmol) of anhydrous p-toluenesulfonic acid and 0.241g of 4-bromoboronic acid in dichloromethane, add 5g of molecular sieve type 5A, and stir evenly at 0°C for 2h.

[0024] 2. Heat 20g of 25% ammonia water, and the generated ammonia gas is passed into the reaction solution after passing through the gas drying processor. Add 20g of ammonia water every 4h until 24h, adding 120g of ammonia water in total.

[0025] 3. After the molecular sieves were removed by suction filtration, the filtrate was washed once with 10 mL of 0.5 mol / L hydrochloric acid solution, 0.5 mol / L sodium hydroxide solution and saturated NaCl solution respectively.

[0026] 4. Dry the organic phase with anhydrous sodium sulfate, remove the desiccant, distill and recover dichloromethane to obtain crude p-toluenesulfonamide, wash with distilled water and dry to obtain white crystals, weighing 0.53g

[0027] 5. Through liquid chromatography analysis, the active ingredient is 98.8%, the...

Embodiment 3

[0029] 2. 1. Dissolve 3.444g (20mmol) of anhydrous p-toluenesulfonic acid and 0.31g of 3-bromoboronic acid in dichloromethane, add 5g of molecular sieve type 5A, and stir evenly at 0°C for 2h.

[0030] 2. Heat 20g of 25% ammonia water, and the generated ammonia gas is passed into the reaction solution after passing through the gas drying processor. Add 20g of ammonia water every 4h until 24h, adding 120g of ammonia water in total.

[0031] 3. After the molecular sieves were removed by suction filtration, the filtrate was washed once with 10 mL of 0.5 mol / L hydrochloric acid solution, 0.5 mol / L sodium hydroxide solution and saturated NaCl solution respectively.

[0032] 4. After the organic phase was dried with anhydrous sodium sulfate, the desiccant was removed, dichloromethane was recovered by distillation, and the crude product of p-toluenesulfonamide was obtained, which was washed with distilled water and then dried to obtain a white crystal weighing 0.395 g.

[0033] 5. T...

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Abstract

A method for preparing para toluene sulfonamide by directly amidating para-toluenesulfonic acid comprises the following steps: (1) anhydrous para-toluenesulfonic acid is dissolved in dichloromethane, a catalyst, namely organic boronic acid, and a 5A molecular sieve are added in a mixed solution, and the mixed solution is uniformly stirred for a certain time under the condition that the temperature is controlled to be -10 to 0 DEG C; (2) an ammonia gas is introduced at the -10 to 0 DEG C for reaction; (3) after the reaction is finished, suction filtration is conducted on the reaction liquid to remove the molecular sieve, and then washing is respectively performed once with an acid solution, an alkali solution and a salt solution; (4) an organic phase is dried through anhydrous sodium sulfate, then a drying agent is removed, a dichloromethane solvent is subjected to distillation recovery, and crude para toluene sulfonamide is obtained; (5) weighing is performed after washing with distilled water and drying, and the product purity is analyzed through liquid chromatography. The complexation is generated between organic boric acid energy and oxygen on a sulfonic acid molecule, the reaction activity of the para-toluenesulfonic acid is improved, ammonia molecules are easily combined with sulfur to generate amide, the whole reaction energy consumption is low, no waste acid is discharged, and the yield of para toluene sulfonamide is about 40%.

Description

technical field [0001] The invention relates to a method for preparing p-toluenesulfonamide by direct amidation of p-toluenesulfonic acid, a method for preparing p-toluenesulfonamide by catalytic sulfonamide reaction, belonging to the field of organic chemistry. Background technique [0002] P-toluenesulfonamide is widely used in organic synthesis, mainly for the synthesis of chloramine-T and chloramphenicol, and also for the synthesis of fluorescent dyes, plasticizers, synthetic resins, coatings, disinfectants and brighteners for wood processing, etc. , has considerable application value. The Chinese patent document "CN 102584647A" reports the industrial production method of p-toluenesulfonamide. The method adopts multi-pot series reaction, and p-toluenesulfonyl chloride and ammonia are continuously aminated in a methylene chloride solvent in a countercurrent absorption mode to form amides. . Although it has realized the up-to-standard discharge of ammonia in the tail gas...

Claims

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Application Information

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IPC IPC(8): C07C303/38C07C303/44C07C311/16
Inventor 吴建一张洋徐聪周大鹏王宏亮徐文梅顾群峰刘丹
Owner 浙江嘉福新材料科技有限公司
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