Production Of Vinylidene Fluoride By Catalytic Cracking Of1,1-difluoro-1-chloroethane Under Low To Medium Temperature

This work introduces the production and application background of vinylidene fluoride, analyzes the features of production process of vinylidene fluoride from multiple raw materials, especially for the preparation of vinylidene fluoride by cracking1,1-difluoro-l-dichloroethane. According to pertinent literature, combining with the pilot research results, we determined to employ the vinylidene fluoride preparation process by catalytic cracking1,1-difluoro-1-chloroethane under medium-low temperature.The change of catalyst, reaction temperature and space velocity were studied, as well as the proportion of inter gases, in order to know the effect factors of the process. When the reaction temperature ranged from400to450℃, space velocity ranged from80to160per hour, the catalysts BaCl2/C and CsF/C have good performance. The conversion of R142b reached88percent and selectivity of VDF reached95percent. External diffusion was verified to have influence on the reaction by studying the reaction’s characteristics in fixed bed reactor and gradientless reactor. The solution was purposed to decrease or eliminate the effect of external diffusion by increasing linear velocity of material appropriately. We have preliminarily evaluated the stability and lifetime of the catalyst, and drawn the conclusion:the catalyst is stable under the temperature ranged400to450℃and the catalysis activity decline is very small after having reacted96hours.Catalytic cracking reaction greatly reduces the reaction temperature and the energy consumption comparison with pyrolysis process. The conversion of R142b approaches the industrial method and the selectivity of VDF is higher than the industrial method under450℃. Further research on the project can provide a scientific basis for VDF production technology reform.