N-contained Ionic Liquid Modified Ru-based Catalyst Used In Acetylene Hydrochlorination

The energy structure determines that the hydrogen chlorination of acetylene is still the mainstream process for PVC production in our country.However,the HgCl₂/AC catalyst used in industry is easily volatile and deactivated,which causes serious environmental pollution and endangers human health.Therefore,it is urgent to develop green and efficient non-mercury catalyst.In this work,we aimed at exploring a novel Ru-based catalyst with high activity and stability.The N-contained ionic liquids were successfully applied to the preparation of Ru-based catalysts using supported ionic liquid technology.In addition,these synthetic catalysts were evaluated in acetylene hydrochlorination reaction and analyzed by a series of characterization methods to explore the influence of N-contained ionic liquids on Ru-based catalysts.Firstly,the catalytic performance and mechanism of Ru-[TMG]ILs/AC catalysts were investigated.The initial conversion of acetylene over Ru10[TMG]HCl/AC catalyst is 99.3%and decreases to 91.2%after 48 h under the conditions of T=170°C,GHSV?C₂H₂?=360 h^-1,V?HCl?/V?C₂H₂?=1.1,and the selectivity of vinyl chloride is about 99.9%.The characterization results of TGA,XPS and TPD show that the addition of[TMG]HCl ionic liquid inhibits the formation of carbon deposition and regulates the valence distribution of Ru species on the surface of the catalyst.Furthermore,[TMG]HCl ionic liquid makes more active component Ru⁴⁺and inhibits the reduction of Ru⁴⁺,thus improving the activity and stability of the Ru-based catalyst.Then,the activity and stability of Ru-QAILs/AC catalysts were investigated.In the 200 h life evaluation,0.1Ru15TBAH/AC catalyst achieves 99.5%acetylene conversion and 99.5%vinyl chloride selectivity,maintaining stability during the reaction process.A series of characterizations reveal the reasons why TBAH improves the performance of Ru-based catalyst:?1?The dispersion of Ru species increases.?2?The formation of carbon in the reaction is strongly inhibited,and the amount of carbon accumulated in 48 h reaction is only 0.98%.?3?The valence distribution of Ru species is regulated,and the Ru⁴⁺content increases.?4?The interaction between Ru species and TBAH makes the activity of Ru-based catalyst stable.The researches in this paper have a guiding significance for the co-catalytic effects of ruthenium and ionic liquids in acetylene hydrochlorination.The greatest advantage of ionic liquids is that they can solve the problem of carbon deposition in the reaction.Therefore,the later study should be put at the methods of stabilizing high valence ruthenium based on the use of ionic liquid.