A kind of method for preparing vinylidene fluoride monomer

Abstract

The invention relates to a method for preparing a vinylidene fluoride monomer. The method is characterized by comprising the following steps: preheating and mixing water and 1,1-difluoro-1-chloroethane and feeding the mixture into a cracking tube, quenching reacted cracking gas, removing HCl, drying and feeding the dried gas to a rectifying tower to obtain the high-purity vinylidene fluoride monomer. By the method, the problems of carbon deposition, clogging of a pipeline and the like can be decreased, the selectivity and reaction efficiency can be effectively improved, the reaction temperature is decreased and thus the energy consumption can be reduced, the energy consumption is substantially reduced and the pollution is decreased.

Description

technical field

[0001] The invention relates to a method for preparing vinylidene fluoride, in particular to a method for preparing vinylidene fluoride through a water dilution method cracking process. Background technique

[0002] Vinylidene fluoride, referred to as VDF, is mainly used for homopolymerization or copolymerization with other monomers to produce polyvinylidene fluoride. At present, a lot of research has been done on the preparation process of vinylidene fluoride monomer. Different processes are used to prepare it according to different raw materials. In industry, difluorochloroethane (R142b) is often used as raw material. Prepared by cleavage reaction in the tube. Patent CN101003460 uses nitrogen to dilute the reaction gas and a U-shaped series reaction tube, and the volume ratio of high-purity nitrogen to R142b is 0.5:1.0 to input into the cracking tube for reaction. Although the conversion rate of VDF increased by 5% compared with that before the improvemen...