Method for preparing tetrachloroethylene by liquid-phase catalysis of pentachloroethane

Abstract

The invention relates to a method for preparing tetrachloroethylene through pentachloroethane liquid-phase catalysis, which comprises the following steps of: an intermittent method: by using high-purity pentachloroethane as a raw material, adding a metal halide as a catalyst according to the percentage by weight, stirring and heating in a reactor, and intermittently reacting and distilling under a normal pressure to obtain a crude tetrachloroethylene product; or a continuous method: by using the prepared crude tetrachloroethylene product as a mother solution, adding the metal halide as the catalyst, stirring, heating, then adding the high-purity pentachloroethane, maintaining the reaction, then heating to prepare the crude tetrachloroethylene product, and continuously adding the high-purity pentachloroethane to continuously produce the crude tetrachloroethylene products with the same volume; and carrying out water-alkali washing for the crude products prepared by the two methods to be neutral, separating, drying and rectifying to obtain a tetrachloroethylene finished product. The environmental-protection difficult problem of serious environmental pollution brought by traditional calcium-hydroxide saponification is radically solved, particularly the usage amount of the catalyst is small in the continuous method, materials are continuously fed and produced, the method is simpler and more labor-saving to operate, the cost is low, the method is suitable for large-batch production, the utilization ratio of the materials is high, and the purity of the prepared product reaches up to more than 99.8 percent.

Description

technical field [0001] The invention relates to a method for preparing organic chlorinated hydrocarbons, in particular to a method for preparing tetrachloroethylene by liquid-phase catalysis of pentachloroethane using pentachloroethane as an initial raw material. Background technique [0002] Tetrachlorethylene is an important organic chlorinated hydrocarbon, mainly used as organic solvent, dry cleaning agent, metal degreasing agent, and also used as an anthelmintic drug. In addition, tetrachlorethylene can be used as fat extractant, refrigerant F The intermediates of -113, HCFC-123 and HCFC-124 can also be used as the main raw materials for the production of HFC134a and R125, which are substitutes for chlorofluorocarbons. , Reducing the emission of ozone-depleting substances (ODS) is steadily advancing under the synergy of countries all over the world. At present, the refrigerants R22 and R502, which are used in the largest amount in the refrigeration industry, have been c...

AI Technical Summary

Problems solved by technology

However, the material requirements of gas-phase catalytic cracking equipment are high, the investment is huge, the reaction temperature is as high as 205 ° C ~ 290 ° C, the energy consumption is large, the catalyst is expensive, and the production cost is high.

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