Synthesis of C4 Olefins from Acetylene over Supported Copper Catalysts

Conversion of acetylene to C-4 olefins enables on-purpose synthesis of C-4 olefins using abundant natural gas resource due to acetylene can be synthesized from methane or ethane. In this study, Cu-based catalysts supported on SiO2, ZSM-5 and mordenite (MOR) were tested for acetylene hydrodimerization. Effect of promoters including Ru, Ga, Ag and Pd on the acetylene conversion and C-4 olefins selectivity are investigated. The structures of these catalysts were characterized by TEM, XRD, BET, H-2-TPR, NH3-TPD and XPS measurements. Results showed that temperature, pressure and hydrogen partial pressure had positive effect on acetylene conversion. In the presence of Ru promotor, 100 % acetylene conversion and 87 % selectivity to C-4 olefins were achieved over Cu/MOR catalyst under conditions of 0.1 MPa and 200 degrees C. The mechanistic aspect of acetylene hydrodimerization was elucidated where the C-4 intermediate was formed by the reaction between [Cu]-C2H2 pi-complex and [Cu]-C2H2 sigma-complex which were transformed to 1,3-butadiene and butene.