Study On Construction And Performance Of The New Mercury Free Catalyst For Vinyl Chloride Synthesis

Polyvinyl chloride（PVC）is a kind of polymer material obtained by polymerization of vinyl chloride（VCM）.It is one of the most popular general plastics.Vinyl chloride is an important monomer.At present,the industrial synthesis methods mainly include ethane oxychlorination method,ethylene method and acetylene method.Based on the situation of rich coal and poor oil in China,acetylene process is widely used because it does not rely on oil,and has the advantages of simple process,mature technology and less investment.This method uses mercuric chloride as catalyst and has many advantages,such as low cost,good selectivity and high activity.It is easy to sublimate in the process of preparation and use,which is harmful to the ecological environment and affects the performance of the catalyst.Therefore,the research and development of non-toxic and environment-friendly mercury free catalyst to fundamentally solve the problem of mercury pollution is an important work to realize the sustainable development of chlor alkali industry.Researchers have carried out extensive exploration and research.A series of catalysts have been designed and developed,among which gold catalyst has the advantages of high activity,green and simple preparation method,but there are still some difficulties in industrialization,such as poor stability and high cost.Based on our predecessors,The catalytic performance of activated carbon supported gold catalyst for hydrogen chlorination of acetylene was further studied.In view of the poor stability of gold catalysts,Additives were added to modify,Exploring optimization schemes;Content of the thesis is divided into two parts:（1）Cu Au bimetallic catalyst system prepared by organic aqua regia treatment;（2）Zr O₂Au@AC catalyst system modified by transition metal oxide Zr O₂.In order to develop non-toxic and environmentally friendly non-mercury catalysts,a series of structural characterizations and related reaction mechanisms have been carried out.The main results are as follows:（1）In view of the problems of low environmental protection,high cost and easy reduction and deactivation of Au based catalysts in industrial production,Change ordinary aqua regia to organic aqua regia（Yar）,Preparation of high performance,low loading（0.2wt%）bimetallic Au based catalyst Cu₁Au@AC（Yar）,When the reaction conditions T=180°C,volume airspeed=1500 h^-1,VCM selectivity approaches 100%,The conversion rate reached 79.9%,After 20 h of continuous reaction,the conversion rate decreased only3.4%,While the preparation process is more environmentally friendly,Catalyst stability is obviously better than that of Cu1Au@AC（ar）catalyst prepared by common Wang Shui method,S、N species produced by organic aqua during the reaction,Auⁿ⁺active species not only through chemical anchoring and electronic action,And it has inhibitory effect on its reductive inactivation,At the same time stabilize the Cu²⁺of auxiliaries,More stable Cu⁰electron donor function and Cu²⁺oxidant function,The overall stability of the catalyst is improved.（2）The ZrO₂Au@AC catalysts were prepared by adding zirconia and transition metal oxide modification to Au active species of the catalysts.the strong electronic synergy between Zr O₂and Au active species was found,which changed the distribution of electrons on the surface of Au active species,reduced the electron cloud density of Au active sites,and then enhanced the adsorption of HCl by catalysts.At the same time,the Zr O₂Au@AC catalyst has excellent anti-aggregation and anti-reduction ability,and then improves its catalytic stability.