Catalyst used for preparing tetrachloroethylene and its preparation method and use

Abstract

The invention relates to novel catalyst to prepare tetrachloroethylene in carbon tetrachloride gas-phase catalysis. The invention is characterized in that the catalyst carrier is prepared from soluble salt solution or mixed solution with ammonia in coprecipitation method. And then one or two of the mixtures such as the compounds of platinum, palladium and nickel, etc, together with one or a plurality of the mixtures such as the compounds of silver, cobalt, tin, zinc, copper or iron is / are loaded on the catalyst carrier in conventional equivalent impregnation method or excessive impregnation method. One or two of the composite oxides of alumina, zirconia, silica and titania is / are used as the carrier or carriers of the catalyst. One or two of platinum, palladium or nickel and one or two of silver, cobalt, tin, zinc, copper and iron are used as the active components to form multi-metal catalyst. The catalyst prepared in the method of the invention maintains high transformation rate of carbon tetrachloride, at the same time reduces the production of by-products such as methane, maintains high selectivity of tetrachloroethylene, and maintains a long service life of the catalyst.

Description

technical field [0001] The invention relates to the technical field of catalysts, and more specifically, the invention relates to a catalyst for preparing tetrachlorethylene by a carbon tetrachloride gas-phase catalytic method and a preparation method thereof. Background technique [0002] At present, the methods for dealing with carbon tetrachloride mainly include thermodynamic incineration, catalytic incineration and catalytic hydrogenation. Both thermodynamic incineration and catalytic incineration are energy-consuming processes and will also cause secondary chlorine pollution. These two methods are only suitable for the treatment of a small amount of carbon tetrachloride. The traditional catalytic hydrogenation is to prepare chloroform by catalytic hydrogenation and dechlorination in the gas phase or liquid phase. Although chloroform is the main raw material for the production of refrigerant HCFC-22, it will also be subject to certain restrictions in future use. It is pr...

AI Technical Summary

Problems solved by technology

[0003] The traditional carbon tetrachloride catalytic method for preparing tetrachlorethylene is to catalyze carbon tetrachloride for thermal decomposition at high temperature. For example, US3364272 discloses that the thermal decomposition temperature is 800°C, and US2447410 discloses that the thermal decomposition temperature is 1300~1400°C. Although the above The method can achieve a higher initial conversion rate and selectivity to tetrachlorethylene, but the catalyst is easily deactivated due to carbon formation at a higher temperature for thermal decomposition, and a higher temperature requires more energy, thus increasing the cost , has not yet achieved industrialization in transformation technology