Experimental and theoretical insights into the cyclotrimerization of acetylene during vinyl acetate synthesis

Abstract

Abstract In the actual vinyl acetate production process, benzene is a very harmful by-product for the quality of the product. In this work, the experimental method and DFT method are combined to study how the by-product benzene is produced during the production of vinyl acetate by acetylene gas-phase. The catalysis of zinc acetate/activated carbon catalyst is the main reason for the formation of benzene from acetylene. Acetic acid can reduce the formation of benzene. The reaction pathway CHCH\u202f+\u202fCHCH\u202f→\u202fCHCHCHCH, CHCHCHCH\u202f+\u202fCHCH\u202f→\u202fC6H6 is the most probable reaction path of acetylene to benzene. Acetylene can generate benzene through a two-step elementary reaction. The activation barrier is 0.25\u202feV and 0.86\u202feV, respectively. Acetic acid has a stronger adsorption at the active site than acetylene. The competitive adsorption of acetylene and acetic acid is an important reason why acetic acid can reduce acetylene to benzene.