Study On The Synthesis Of Vinyl Chloride By Dehydrochlorination-Hydrochlorination Coupling

Polyvinyl chloride(PVC)is one of the world's five major engineering plastics and has a very wide range of applications in all walks of life.Vinyl chloride monomer(VCM)is mainly used for the synthesis of PVC.With the gradually increasing demand for vinyl chloride,the production research and development of technology are of great importance.At present,industrial production of vinyl chloride mainly depend on petrochemical route,that is obtained from cracking of 1,2-dichloroethane.But the traditional manufacturing of vinyl chloride has many problems,such as furnace tube easy coking,short production cycle,high energy consumption and other major problems.And the process have a lot of byproducts,in order to ensure the selectivity of VCM,the conversion of EDC was only 50 percent,the separation cost between raw material and products was very high.In response to these problems,the innovation of this study is to find a suitable catalyst and support,which had catalytic activity both for dehydrochlorination of 1,2-dichloroethane and hydrochlorination of acetylene.BaCl2 was chosen as active ingredients and activated carbon was chosen as support.The effect of different materials and different approaches to catalyst activity and product selectivity were also studied,And the structure and properties of catalyst were characterized by BET,XRD,NH3-TPD,etc.the results showed that weak acid sites on the catalyst surface had a significant impact on product selectivity.The catalytic performance of dichloroethane and acetylene reaction was investigated further.the effects of various factors on the catalytic performance were also studied by changing the reaction temperature,reaction time,ratio of raw materials.The results showed that when the temperature was 320 ?,a space velocity was 300?500h-1,C2H4Cl2/C2H2 ratio was 1.2,the conversion of dichloroethane was the best.Under certain conditions,the catalyst represented good stability,as the reaction proceeds,the conversion rate reduced gradually,when the reaction time was to 100h,The catalyst loss the activity basically.The main reasons for deactivation of the catalyst were as follows:poisoning,carbon deposition and sintering.And carbon deposition on the catalyst surface was eliminated by calcination and treatment of HNO3 at a certain level,and the deactivated catalyst restored some extent activity.Not only does this new technology solve the problem of mercury pollution,but also provide a unique synthetic route which lays the foundation for the synthesis of vinyl chloride.