Acetylene Hydrochlorination By Gold And Copper Bimetallic Catalysts Supported By ZIF-8 Derived NC And Activated Carbon

Vinyl chloride（VCM）is the monomer of the important chemical products of PVC（PVC）.The global annual production of PVC are more than 40 million tons,while China accounted for more than 60% of them.Based on China’s energy status—lacking of oil,less gas,more coal,more than 75% of PVC are produced by acetylene hydrochlorination with coal.In view of the fact that more than 70 countries and regions have signed the "Minamata Convention" in the world,which is stipulated that all countries that have signed the Convention are prohibited from producing and importing mercury-containing products from 2020 onwards.So it is an urgent need to research and develope new and efficient mercury-free catalysts to PVC production industry.This thesis explored three catalysts with different carriers,and the specific work is as follows.:（1）Metal-organic framework compounds（MOFs）is a class of porous coordination polymer with ultra-high surface area.In this paper,ZIF-8,which is structurally stable and easily synthesized,was used as a precursor to calcine and carbonize to form a nitrogen-doped carbon structure（NC）.The NC-950 carbonized at 950 ° C has the best reactivity in acetylene hydrochlorination.The results showed that NC-950 had the highest activity of NC-950 modified by aqua regia.When the reaction temperature was 180 oC,and the GHSV（C₂H₂）was 50 h-1,the acetylene conversion rate was up to 50% or more,which is a high-performance catalyst.In the study,XPS characterization revealed that pyrrole-type N had a significant catalytic effect in the reaction,and as the reaction progressed,the pyrrole-type N was gradually converted to pyridine-N,and the catalytic effect was gradually decreased.（2）Au1Cu1 / NC-950 catalyst prepared with NC-950 carrier was superior to Au1Cu1 / AC catalyst with activated carbon as carrier.The reason for this is that N in the carrier can promote the adsorption of the reaction gas C₂H₂ on the catalyst.It can also induce the active center Au to form Au-Cl bonds with HCl and to polarize,thereby enhancing the catalyst activity.（3）The modification of S is significant for AuCu / AC catalyst.In the absence of S modification,the active components Au NPs and Cu NPs agglomerate due to their high surface energy,resulting in catalyst deactivation;but after S modification,it can effectively promote the dispersion of active nanoparticles,thereby weakening the effect of inactivation due to reunion.In addition,the addition of S can make the activated carbon carrier layered separation,so that the specific surface area increases,effectively enhance the catalyst activity and stability.