Ruthenium Complex Catalytic Acetylene Hydrochlorination Reaction

Vinyl chloride monomer（VCM）is mainly used for the synthesis of polyvinyl chloride（PVC）,which is one of the world’s top five general plastics.At present,industrial production process of VCM mainly includes the acetylene-based and the ethylene-based method.The ethylene-based method is mainly used in western developed countries or oil-rich countries.However,in China,acetylene-based method is the main synthesis method,owing to the lack of oil and gas but the plenty of coal resources.The current industrial catalyst for the production of VCM via the acetylene-based method is mercuric chloride catalyst.Mercury chloride is highly toxic and volatile,seriously threatening human health and environmental safety.Therefore,it is imperative to explore a green and environmentally friendly mercury-free catalyst for the acetylene hydrochlorination to produce VCM.Firstly,the catalytic performance of Ru（Ⅳ）complex catalyst（NH₄）₂RuCl₆/AC was studied.The result shows that the catalytic performance of the complex catalyst（NH₄）₂RuCl₆/AC is better than that of the single metal RuCl₃/AC catalyst.The conversion of acetylene is 90.5%under the condition of 170 ^oC and the acetylene space velocity of 180 h^-1.The（NH₄）₂RuCl₆/AC catalyst contains a large amount of main active component Ru（Ⅳ）,which is one of the main reasons for the excellent catalytic activity.The presence of NH₄⁺in the complex can reduce the amount of coke deposition during the reaction.In addition,the presence of NH₄⁺can also enhance the adsorption ability of the reactant hydrogen chloride and the desorption ability of the product VCM on the Ru-based catalysts.Then,in order to improve the catalytic activity and stability of the（NH₄）₂RuCl₆/AC catalyst,N-butylpyridine type ionic liquids were introduced and（NH₄）₂RuCl₆/AC-IL complex catalysts were prepared.The result shows that the catalytic activity and stability is obviously improved when the ionic liquid is added.Under the same conditions,the optimal 1%Ru10%[BuPy]PF₆/AC catalyst shows an acetylene conversion of 99.4%.The addition of ionic liquids can stabilize the active species Ru⁴⁺and restrain the reduction of Ru⁴⁺to Ru or Ru³⁺during the preparation of the（NH₄）₂RuCl₆/AC-IL complex catalysts.In addition,the addition of ionic liquid can greatly improve the anti-carbon deposition properties of the Ru-based catalyst,enhance the adsorption ability of the reactant hydrogen chloride and the desorption ability of the production VCM,consequently improving the catalytic activity and stability of the（NH₄）₂RuCl₆/AC-IL complex catalysts.