Preparation Of Heteroatom-modified Low Ruthenium Catalysts For Hydrochlorination Of Acetylene

PVC is widely used in medical treatment,medical equipment,electronic products,automobile industry,construction and other fields.PVC is a thermoplastic resin which is polymerized by vinyl chloride?VCM?under the action of initiator.So VCM is an important monomer for the production of PVC.At present,the catalyzed for acetylene hydrochlorination to produce vinyl chloride in industrial applications is activated carbon-supported mercury catalyst?HgCl₂?which volatilizes toxic mercury vapor during higher temperature reaction.As a result,deactivation of catalyst,environmental pollution,the health of staff members is endangered.At the same time,there is no mature recovery process for lost mercury.So,how to produce vinyl chloride by acetylene hydrochlorination under the conditions of safety,high efficiency,green,pollution-free and sustainable development is an urgent problem to be solved.This promoted researchers to development new mercury-free catalysts.This article mainly studies propylene diamine,thiourea,and malonic acid in the catalytic process of acetylene hydrochlorination with low ruthenium catalyst.Using Ru instead of Hg as the active component solves the problems of Hg resource loss and environmental pollution.Decline the Ru content to 0.25%,greatly reduce the economic cost,and making the catalyst have a better industrial application prospect.Through the import of additives,the activity and stability have been significantly improved of the catalyst,which provides ideas for the preparation of catalysts for industrial production of vinyl chloride.The following three parts are the main research contents:?1?RuCl₃ is the precursor and diaminopropane is the N source.A series of catalysts were prepared.The catalysts were tested under the conditions of T=170?,GHSV?C₂H₂?=180 h^-1,V_?HCl?/V_?C2H2?=1.15.The results after 1300 minutes of testing showed that the activity of catalyst 0.25%Ru/AC-3D-300 was 16%higher than that of catalyst 0.25%Ru/AC,and the stability of catalyst was obviously improved.Characterization results show that the dispersion of ruthenium species on the carrier surface can be improved by propylenediamine,effective inhibition the formation of carbon deposition and encouragement the relative number of high-valent ruthenium species.Therefore,the catalytic activity and stability of the catalyst were improved.?2?RuCl₃ is the precursor and thiourea is both S and N source.A series of catalysts were prepared.The catalysts were tested under the conditions of T=170?,GHSV?C₂H₂?=180 h^-1,V_?HCl?/V_?C2H2?=1.15.The results after 1800 minutes of testing showed that the activity of catalyst 0.25%Ru-2T/AC was 24.8%higher than that of catalyst 0.25%Ru/AC,and the stability of catalyst 0.25%Ru-2T/AC is obviously higher than that of catalyst 0.25%Ru/AC in the reaction process.Characterization results show that the dispersion of ruthenium species on the carrier surface can be improved by thiourea,effective inhibition the formation of carbon deposition while also inhibiting the reduction of high-valent ruthenium,the interaction between carrier and active components was improved,enhanced the adsorption capacity of the reactants and the desorption capacity of the product,consequently enhancing the catalytic activity and stability.?3?RuCl₃ is the precursor and propanedioic acid is the O source.A series of catalysts were prepared.The catalysts were tested under the conditions of T=170?,GHSV?C₂H₂?=180 h^-1,V_?HCl?/V_?C2H2?=1.15.The results after 500 minutes of testing showed that the activity of catalyst 0.25%Ru-5P/AC was 6.1%higher than that of catalyst 0.25%Ru/AC.Characterization results show that an increase in the number of surface oxygen-containing functional groups can enhance the hydrophilicity of the catalyst and increase the dispersion of the active component,producing more high-valent ruthenium,inhibiting the formation of carbon deposition,consequently enhancing the catalytic activity and stability.