Theoretical insight into the effect of impurity on the acetoxylation of ethylene to form vinyl acetate: A DFT study of acetylene coversion on PdAu(1 0 0) surface

• Mechanism of acetylene conversion on PdAu(1 0 0) surface was studied by DFT method. • The oxidation, hydrogenation and polymerization reaction of acetylene may occur. • CO 2 and aldehydes are the main products of acetylene conversion. • Acetylene has little effect on the acetoxylation of ethylene to form vinyl acetate. Vinyl acetate (VA) is an important organic chemical material, which is mainly obtained from ethylene acetoxylation. The raw material, ethylene, usually contains a small amount of acetylene. To understand the effect of acetylene on vinyl acetate system, we used density functional theory (DFT) to explore the pathways and the main products of acetylene conversion on PdAu(1 0 0) surface. DFT calculation results suggest that acetylene is quite active on PdAu(1 0 0) surface and the Pd-Au catalyst can catalyze the oxidation, hydrogenation and polymerization reaction of acetylene. In all reactions, oxidation reaction is the most likely to occur due to low energy barrier. CO 2 and aldehydes as oxidation products will exist simultaneously in the reaction system. Hydrogenation and polymerization of acetylene have a mute effect on vinyl acetate system. We can draw a preliminary conclusion that trace acetylene has little effect on vinyl acetate system.