A kind of preparation method of 2-chloro-3,3,3-trifluoropropene

Abstract

The invention discloses a preparation method of 2-chloro-3,3,3-trifluoropropene, which mainly includes the following steps: (1) passing 3,3,3-trifluoropropene and chlorine gas into the ,3-dichloro-1,1,1-trifluoropropane in the light chlorination reactor; (2) the reactants in the photochlorination reactor in step (1) are continuously added to the rectification tower, and the tower still Obtain 2,3-dichloro-1,1,1-trifluoropropane; (3) use a metering pump to add 2,3-dichloro-1,1,1-trifluoropropane obtained in step (2) into gasification After being vaporized, it is mixed with oxygen-deficient nitrogen gas, and then enters a fixed-bed reactor equipped with a catalyst for gas-phase catalytic dehydrochlorination; (4) Pass the reaction gas from the fixed-bed reactor in step (3) through the primary cooler, The secondary cooler is condensed to obtain the material of crude 2-chloro-3,3,3-trifluoropropene, and the crude 2-chloro-3,3,3-trifluoropropene is purified by distillation. The invention has the advantages of high product selectivity, simple process and easy industrialization.

Description

technical field [0001] The invention relates to the technical field of synthesis of intermediates, in particular to a preparation method of 2-chloro-3,3,3-trifluoropropene. Background technique [0002] 2-Chloro-3,3,3-trifluoropropene (HCFO-1233xf) can be used as an intermediate for the preparation of various fluorocarbons, such as for the synthesis of HFC-245fa, HFO-1234yf, etc., and can also be used as a monomers of a polymer. [0003] There are many preparation methods for HCFO-1233xf, for example: CN109651077A uses a chromium-containing fluorination catalyst to catalyze the reaction of polyhalopropene and HF under gas phase conditions to prepare HCFO-1233xf. This method requires high water content in HF and uses Chromium is catalyzed by heavy metals, and the pollution is relatively large. WO2007079431 and WO2008054781 use 1,1,2,3-tetrachloropropene as a raw material to synthesize HCFO-1233xf by gas-phase fluorination under the action of a chromium catalyst. This method...

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Problems solved by technology

[0003] There are many preparation methods for HCFO-1233xf, for example: CN109651077A uses a chromium-containing fluorination catalyst to catalyze the reaction of polyhalopropene and HF under gas phase conditions to prepare HCFO-1233xf. This method requires high water content in HF and uses a Chromium heavy metal catalysis, large pollution

WO2007079431 and WO2008054781 use 1,1,2,3-tetrachloropropene as a raw material to synthesize HCFO-1233xf by gas-phase fluorination under the action of a chromium catalyst. The catalyst is easily deactivated in this method, and 2-chloro-3,3,3 - The selectivity of trifluoropropene decreases gradually with the activity

US20090030247 uses 1,1,1,2,3-pentachloropropane and 2,3,3,3-tetrachloropropene as raw materials, adding amines, hydroquinones or other stabilizers to synthesize HCFO-1233xf by catalytic fluorination , the product selectivity of this method is low, and the purpose of suppressing catalyst deactivation cannot be well achieved

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