Method for synthesizing paraphthaloyl chloride (TPC) through continuous flow in micro-channel reactor

Abstract

The invention belongs to the technical field of organic synthesis, and in particular relates to a method for synthesizing paraphthaloyl chloride through continuous flow in a micro-channel reactor by taking phthalic acid and phosgene / triphosgene as raw materials. The invention aims to provide a micro-channel continuous flow reaction manner for performing terephthalic acid chlorination so as to synthesize paraphthaloyl chloride. Compared with the existing process, the process disclosed by the invention has the characteristics of being accurate in control of reaction conditions, high in phosgene / triphosgene utilization rate, low in catalyst usage, high in TPA (terephthalic acid) conversion ratio with reaction time of decades of seconds, high in TPC yield and the like.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for continuously synthesizing terephthaloyl dichloride in a microchannel reactor using terephthalic acid and phosgene / triphosgene as raw materials. Background technique [0002] Terephthaloyl chloride (TPC) is a white solid or colorless needle-like crystal, mainly used as polyparaphenylene terephthalamide (abbreviated as para-aramid fiber, 1414 or PPTA) and polysulfone fiber Polymerization monomer, in addition, it has certain applications as a modifier of high polymers, intermediates in pesticides and pharmaceutical industries, etc., and has broad prospects for development and utilization. [0003] The development of TPC in China mainly depends on the development of aramid fiber 1414. Since the production of aramid fiber has high requirements on the purity of TPC products, it needs to meet the requirements of purity>99.9%, monoacyl chloride (TMC)...

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Problems solved by technology

[0005] Disclosed in CN1054062A with TPA, PCl 3 , Cl 2 Synthesize TPC as a raw material, the reaction time is as long as 20 hours, PCl 3 High consumption, great corrosion to equipment, low product purity, need multiple vacuum distillation, low product yield; TPA and thionyl chloride are used as raw materials in CN104402709A, thionyl chloride is not only a reactant but also a solvent, and chlorination Thionoxide decompression distillation is difficult to remove, and it is easy to have a side reaction with TPC in the rectification process, which produces impurities and affects product quality; in CN101935276A, it is also a synthetic method of thionyl chloride, but it is difficult to recycle with quaternary ammonium salt as a catalyst, increasing Solid waste amount and product cost; CN10180527A discloses that TPA and solid Sanguang are used as raw materials, dichloroethane is used as solvent, and batch reaction is carried out. The utilization rate of solid light is low, the consumption of catalyst is large, and the consumption is high, and solvents need to be desolvated , increase process steps; CN104045498 uses TPA as raw material, no solvent, phosgene method to synthesize TPC intermittently, the reaction time needs several hours, and the phosgene utilization rate is low

Thionyl chloride method: The recovery of raw material thionyl chloride causes severe corrosion to equipment; the product has low purity and requires several vacuum distillations to meet the standard, resulting in high production costs; at the same time, the by-product SO 2 Recycling is troublesome and will cause pollution to the environment; phosgene / triphosgene method: long reaction time, low utilization rate of phosgene / triphosgene, catalyst is easy to decompose and coke when heated for a long time, resulting in dark color of catalyst and low recovery rate, resulting in production high cost

[0007] So far, there has been no research on the synthesis of terephthaloyl chloride from terephthalic acid in a microchannel reactor continuous flow mode

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