Supported ionic-liquid-phase-stabilized Au(III) catalyst for acetylene hydrochlorination

Using high-valent Au(III) catalysis is highly desirable in many reactions; however, it is plagued by the poor stability of Au(III) complexes. Still, conventional catalysts need high Au content makes the high price and demand for Au is one of the major obstacles limiting their large-scale application. Here we demonstrate that stable and catalytically active Au(III) complexes can be obtained using Supported Ionic Liquid Phase (SILP) technology. The resulting heterogeneous Au-IL/AC catalysts combine the advantages of the catalytic species being stabilised in the Au(III) form by forming a Au(III)-IL complex and the need for a less expensive metal catalyst because the active component can be better developed in a homogeneous reaction medium. When used in acetylene hydrochlorination reaction, this catalyst displayed an excellent specific activity and superior long-term stability. Under the same reaction conditions, the Au(III)-IL/AC catalyst shows higher activity and stability towards the vinyl chloride monomer (VCM) than IL-free Au/AC (C2H2 conversion = 72.1% at 180 degrees C compared to 16.1% without IL). It also delivered stable performance within the conversion of acetylene, reaching more than 99.4%, and there was only a 3.7% C2H2 conversion loss after running for 300 h under the reaction conditions of a temperature of 180 degrees C and a C2H2 hourly space velocity of 30 h(-1). Its exceptional ability to maintain the high activity and stability further demonstrated the potential for the replacement of Hg-based catalysts for acetylene hydrochlorination.