Preparation method of 2-bromo-2,2-difluoroacetyl chloride and 2-bromo-2,2-difluoro acetate and recycling method of waste difluoro trichloroethane

Abstract

The invention relates to a preparation method of 2-bromo-2,2-difluoroacetyl chloride and 2-bromo-2,2-difluoro acetate and a recycling method of waste difluoro trichloroethane. The preparation method comprises the following steps: with waste difluoro trichloroethane produced in the production process of dichlorotrifluoroethane as a raw material, carrying out dehydrochlorination to obtain difluoro dichloroethylene, carrying out addition reaction on difluoro dichloroethylene and bromine to obtain difluoro dichlone dibromoethane; reacting difluoro dichlone dibromoethane with sulfur trioxide to obtain 2-bromo-2,2-difluoroacetyl chloride; and reacting 2-bromo-2,2-difluoroacetyl chloride with alcohol or phenol to obtain 2-bromo-2,2-difluoro acetate series products. According to the preparation method and the recycling method, recycling of waste difluoro trichloroethane is realized; 2-bromo-2,2-difluoroacetyl chloride and 2-bromo-2,2-difluoro acetate are prepared by a temperature oscillation method, so that the production cost is reduced; and meanwhile, the preparation method is an environment-friendly technique for producing products.

Description

technical field [0001] The invention belongs to the technical field of preparation of fluorine-containing organic intermediates, and relates to a preparation method and waste of 2-bromo-2,2-difluoroacetyl chloride, 2-bromo-2,2-difluoroacetic acid and ester series compounds Recovery and treatment of difluorotrichloroethane. Background technique [0002] The problem of environmental protection in the chemical production process has always been a topic that chemical technicians need to continuously study and improve. If the waste generated in the chemical production process is discharged directly, it will seriously pollute the environment. [0003] In order to solve this problem, on the one hand, through the continuous improvement of the chemical reaction process route, the use of green and environmentally friendly production technology can reduce or even eliminate the generation and discharge of pollutants in the chemical production process. Another way is to collect the poll...

AI Technical Summary

Problems solved by technology

This method is a feasible synthetic route, but there are selectivity problems: there are by-products of bromodichloroacetate and its derivatives, and there are also difluorodichlorodibromoethane raw materials that are not easy to obtain, and oxygen oxidation engineering is used Amplification has many problems, and it is not easy to achieve industrialized mass production

[0033] The inventor found in the course of the experiment that using mercury salt as a catalyst and using the same amount of sulfur trioxide, even if the reaction exceeds 72 hours, difluorodichlorodibromoethane cannot be completely converted into 2-bromo-2,2-dibromoethane. Fluoroacetyl chloride requires at least twice the amount of sulfur trioxide to completely convert difluorodichlorodibromoethane, and the boiling point of sulfur trioxide (45°C) is the same as that of 2-bromo-2,2-difluoroacetyl chloride ( 50°C), the excess sulfur trioxide will cause difficulties in the post-treatment, and it is difficult to separate the excess sulfur trioxide from 2-bromo-2,2-difluoroacetyl chloride. To obtain pure 2-bromo-2, 2-Difluoroacetyl chloride is very difficult

The toxicity of mercury salts is also relatively high, which has a great impact on operators and the environment

In addition, the use of mercury salts as catalysts is too active, and the by-products are complex

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