Improved preparing process for 1,1,1,3,3-pentachloro propane

Abstract

The improved 1, 1, 1, 3, 3-pentachloro propane preparing process includes the telomerization of carbon tetrachloride and chloroethylene in the presence of iron powder catalyst and phosphoric acid ester cocatalyst, settlement separating the reaction product to eliminate coarse iron powder and un-reacted material, water treating the product to eliminate fine iron powder, iron ion complex dissolved in the product and iron salt, and final decompression rectifying to obtain target product. The technological process of the present invention has greatly reduced scaling, decomposition and blocking during product rectification, and is favorable to industrial production.

Description

technical field [0001] The invention relates to an improved preparation method of 1,1,1,3,3-pentachloropropane. Background technique [0002] 1,1,1,3,3-pentachloropropane (referred to as HCC240) is an intermediate for the preparation of 1,1,1,3,3-pentafluoropropane. 1,1,1,3,3-Pentafluoropropane referred to as HFC245fa has excellent physical and chemical properties and is widely used in cleaning, foaming, refrigeration and other fields, especially the physical and chemical properties of HFC245fa are similar to HCFC141b and CFC11, and its ODP value It is zero and has no potential damage to the atmospheric ozone layer, so HFC245fa is an ideal substitute for HCFC141b and CFC11. [0003] According to literature records, HCC240 can be prepared by the telomerization reaction of carbon tetrachloride and vinyl chloride, such as according to U.S. Patent No. 6,313,360B1, HCC240 is produced by tetrachlorethylene and vinyl chloride in the presence of iron powder catalyst and phosphoric ...

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Problems solved by technology

[0003] According to literature records, HCC240 can be prepared by the telomerization reaction of carbon tetrachloride and vinyl chloride, such as according to U.S. Patent No. 6,313,360B1, HCC240 is produced by tetrachlorethylene and vinyl chloride in the presence of iron powder catalyst and phosphoric acid ester co-catalyst According to the preparation process of this patent, the coarse-grained iron powder catalyst, after the reaction is completed, is separated by sedimentation and returned to the reactor for recycling. However, in this preparation process, part of the fine iron powder is suspended in the product stream In the process, it is difficult to separate and recycle through sedimentation. In addition, some iron powder catalysts will form complexes with phosphate co-catalysts or iron salts will be dissolved in the product stream during the reaction. Obviously, these iron complexes and iron Salt also can't be separated and removed by settling, and these iron powders suspended in the product stream and iron complexes and iron salts dissolved in the product stream, if not separated, will not only bring troubles to the rectification operation of the product but also will affect the product yield