Study Of Catalytic Performance Of Nitrogen And Sulfur Co-doped Carbon Supported Gold Catalysts On Acetylene Hydrochlorination

Polyvinyl chloride as one of five general-purpose resins has been widely used in China.At present,most of China's industrial production of vinyl chloride monomer are synthesized through acetylene hydrochlorination methlod.But the use of mercuric chloride catalysts in the process brought lots of problems which restricted its development.With the signing of ?Minamata Convention On Mercuric‘ in 2013,development of the mercury-free catalysts directly related to the future of the vinyl chloride industry.During the study of the mercury-free catalyst,activated carbon supported gold chloride catalyst is considered to be the most promising industrial catalysts candidate,although classic gold catalyst exhibits good conversion and selectivity for the reaction,its poor stability restricts its application.To enhance the interaction between the carrier and the active gold ingredient,we prepared a series of nitrogen and sulfur co-doped carbon materials,on which gold supported.The results showed that after running for 12 h under the reaction conditions of a temperature of 180 °C and a C₂H₂ gas hourly space velocity of 1480 h-1,there was only a 3.8% C₂H₂ conversion loss over Au/NSAC catalyst,which clearly indicated that the stability of the catalyst was greatly improved compared with the 34.1% conversion loss over activated carbon supported AuCl₃ catalyst.The initial C₂H₂ conversion was promoted by 13.2% as well as the stability over the co-doped catalyst.Futher research and analysis show that the hetero atom nitrogen and sulfur play different roles on stablizing the active species in nitrogen sulfur co-doped gold catalysts.Since the presence of nitrogen atoms in the Au/NSAC can increase the electron density of Au³⁺,the Au/NSAC therefore pocesses a stronger ability of adsorbing hydrogen chloride compared to the Au/AC catalyst.While the existence of sulfur atoms could anchor and stablize Au³⁺,improving the reduction temperature of the gold species.With nitrogen and sulfur combined with each other,the nitrogen sulfur co-doped carbon material supported gold catalysts exhibit a more efficient performence.Moreover,this paper reports the application of organic ionic liquid in the preparation of nitrogen sulfur co-doped material,make a thorough inquiry into the effect of prepare temperature on the properties of the nitrogen sulfur co-doped carbon material and the influence of these properties on the gold catalysts performance for acetylene hydrochlorination have also been investigated and discussed in the paper.