Preparation method of p-toluene sulfonyl chloride

Abstract

A preparation method of p-toluene sulfonyl chloride comprises steps as follows: (1), p-toluene sulfonic acid is dissolved in chloroform, an ion liquid cosolvent is added, the mixture is uniformly stirred at the temperature of 0-40 DEG C, and chlorosulfuric acid is dropwise added; (2), after the chlorosulfuric acid is dropwise added, the mixture continues to react at a constant temperature for 1.5-4 h; (3), after the reaction ends, water is added to remove excessive chlorosulfuric acid, a liquid is separated in a separating funnel, and waste acid and an organic layer are obtained; (4), the organic layer is washed with water, a p-toluene sulfonic acid aqueous solution is extracted from an organic phase, wastewater is removed through liquid separation, and then a product layer is obtained; (5), chloroform is removed through distillation, and a finished p-toluene sulfonyl chloride product is obtained. A low-toxicity solvent, namely, chloroform is used, an ion liquid serves as cosolvent, p-toluene sulfonic acid and chlorosulfonic acid have an acyl chlorination reaction, after the reaction is performed to a certain degree, byproduct sulfuric acid and the organic layer are layered, the ion liquid cosolvent changes the distribution coefficient of p-toluene sulfonic acid, and accordingly, the yield of p-toluene sulfonyl chloride is increased.

Description

technical field [0001] The invention relates to a method for preparing p-toluenesulfonyl chloride, belonging to the field of organic chemistry. Background technique [0002] Sulfonyl chloride is an important class of fine organic chemical intermediates, which are widely used in the synthesis of various medicines, pesticides, and dyes. Among them, arylsulfonyl chloride is an important intermediate for the synthesis of sulfonamide drugs, dyes, and insecticides. Sulfonyl chloride can be regarded as a product in which the hydroxyl group in sulfonic acid is replaced by chlorine, and it is a derivative of sulfonic acid. At present, the industrial generation of p-toluenesulfonyl chloride is synthesized by adding p-toluenesulfonic acid to the acid chloride reagent chlorosulfonic acid. Although the reaction conditions are mild, the reaction is stopped when the conversion rate reaches about 80%, and a large amount of unreacted raw material p-toluene Sulfonic acid dissolves in the by-...

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Problems solved by technology

The article "Research on the Synthesis of p-Toluenesulfonyl Chloride" by Chen Zhongxiu, Vol. 18, No. 2 of "Journal of Chemical Engineering of Universities" reported the synthesis of p-toluene from p-toluenesulfonic acid and phosphorus oxychloride Sulfonyl chloride, its used raw material phosphorus oxychloride has pungent odor, is highly toxic, and the phosphorous acid that produces is difficult to remove, is unfavorable for large-scale industrial production; Two (trichloromethyl) carbonate) is raw material, with organic amine as catalyst, reflux reaction in inert organic solvent obtains aryl sulfonyl chloride, the follow-up treatment method in this patent still adopts traditional purification method, needs to remove in filtrate After melting, the vacuum distillation operation is carried out, and the equipment input for subsequent purification operations needs to be increased in industrial applications; the patent document "CN102633687" reports that alkylbenzene is slowly added to chlorine at a temperature of 0°C-45°C under stirring. Sulfonic acid, inorganic salt catalyst, heat preservation reaction for 0.1-10 hours, can obtain sulfonated materials, use ice water precipitation method to separate and purify p-substituted alkylbenzenesulfonyl chloride, this method uses too much chlorosulfonic acid, and the three wastes problem is serious, Serious environmental pollution; patent literature "CN103588683" reports that toluene, chlorosulfonic acid, ammonium chloride, pyridine and sulfamic acid are used as raw materials, after chlorosulfonation reaction, the reaction solution is cooled, vacuum filtered, solvent extracted, After crystallization and drying, p-toluenesulfonyl chloride is obtained. The follow-up treatment method of this patent also adopts the traditional purification method. It needs to carry out vacuum distillation after the filtrate is desolvated. When it is applied in industry, it needs to increase the investment in equipment for subsequent purification operations.

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