Construction And Research Of Acetylene Synthetic Vinyl Chloride Green Catalyst

PVC is one of the most widely used materials,with high plasticity,high strength,good resistance,low production costs and so on.VCM is the most important raw material of PVC,prepared by ethylene method,acetylene method,ethane method and other processes.Limited by Chinese"rich coal,poor oil,less gas"basic national conditions,acetylene method has became the most extensive preparation method.The traditional acetylene process requires the use of mercury chloride as catalyst in the preparation process.Mercury catalyst has excellent catalytic performance,but poor stability.It is easy to volatilize in the process of use,which pollutes vinyl chloride products and easily volatilizes into the air and seriously pollutes the environment.In order to reduce the threats to the environment,it is urgent to find an environment-friendly catalyst with excellentcatalytic performance.In reaction to the phenomenon,the domestic and foreign scholars on low mercury,no mercury catalyst to do a lot of research,few have begun the industrialization on the preliminary test.On the basis of summarizing the research status at home and abroad,the following two research directions are explored in this study:（1）Taking PdCl₂ catalyst as the research object,the ammonia modification method was designed to solve the problems of easy loss and poor stability of Pd-based catalyst during the reaction process.It is found that the modified catalyst introduces the NH₄⁺species,which together with the original Pdmetal forms the NH₄⁺-Pd-Cl structure.It effectively prevents the loss and reduction of Pd²⁺ions,thus ensuring the stability of the catalyst.（2）Consideringthe defects of carbon-prone and high cost of precious metal catalysts in activated carbon carriers,this study also explores a new metalless catalyst with molecular sieve load ionic liquid（IL/Ca X）.IL/Ca X catalysts show better catalytic properties compared to traditional activated carbon catalytic properties.Through the characteristic and theoretical calculation,the acetylene hydrogen chlorination reaction follows the typical L-H system on IL/Ca X,i.e.C₂H₂ adsorbed on the C2 bit H of the ionic liquid and HCl adsorbed on Ca²⁺,the reaction generates the VCM molecule,and further studies the inactive and regenerative structure of the catalyst.