MOMTPPC improved Cu-based heterogeneous catalyst with high efficiency for acetylene hydrochlorination

Abstract

The development of environmentally friendly nonmercuric catalysts for acetylene hydrochlorination reaction mainly focuses on precious metal like Au, Pd and Ru. Non-precious metal based catalyst had much lower activity and stability in this reaction, limiting its practical application. In this work, a novel ionic liquid improved Cu-based heterogeneous catalyst has been designed and successfully synthesized, and it showed the highest catalytic activity and stability among the reported non-precious metal based catalyst used in the reaction of acetylene hydrochlorination. Among many ionic liquids, the (Methoxymethyl) triphenylphosphonium chloride (MOMTPPC) ionic liquid improved Cu-based heterogeneous catalysts has the highest catalytic performance. The optimal 15%Cu@15%MOMTPPC/SAC achieved the conversion of C2H2 of 92.2% under the reaction condition of T=180℃, GHSV (C2H2) of 180 h−1 and VHCl/VC2H2 = 1.2. And under the industrial GHSV (C2H2) of 36 h−1, C2H2 conversion maintains above 98.7% within 360 h. A series of experimental characterizations combined with theoretical calculations indicated that the addition of MOMTPPC ionic liquid can inhibit carbon deposition, prevent the aggregation of Cu species, enhance the dispersion of Cu species and the adsorption of HCl reactant. The stabilization effect of MOMTPPC to Cu is mainly through the hydrogen bond, steric hindrance of MOMTPPC cation and electrostatic effect. The development of Cu@MOMTPPC/SAC catalyst with high efficiency shed light on the potential of replacing the toxic mercuric catalyst with non-precious Cu-based catalyst in the polyvinyl chloride (PVC) industry.