A density functional theory study on the effect of acetylene on vinyl acetate synthesis from acetoxylation of ethylene over Pd-Au catalysts

In this work, the reaction network of acetylene on Pd-Au catalyst was constructed firstly, and the single adsorption configurations and adsorption energies and electronic properties of key species in the reaction network were calculated with Density Functional Theory (DFT). It was found that most of the species tend to be adsorbed on the sites around Pd atoms and acetylene does not occupy the active site of ethylene. Then the energy barrier and reaction energy of the related reaction of acetylene on the Pd-Au surface and the geometric configuration of the transition state were calculated through DFT. Acetylene is highly reactive and oxidation, hydrogenation and polymerization were easy to occur. Among all the reactions, the oxidation reaction had the most competitive advantage. CO2 was the most in the final product, followed by the intermediate product C2H3. CO2 and C2H3 have no adverse effect on the reaction system, so the trace of acetylene in the raw material ethylene had a very weak effect on the vinyl acetate reaction system.

Automated summary

This study constructed a reaction network of acetylene on Pd-Au catalyst and calculated the adsorption configurations, energies, and electronic properties of important species using DFT. The results showed that acetylene tends to adsorb on sites around Pd atoms and does not occupy the active site of ethylene. DFT calculations also revealed that acetylene is highly reactive and oxidation, hydrogenation, and polymerization reactions are favorable. Among these reactions, oxidation has the most competitive advantage, with CO2 being the major product followed by C2H3. The presence of CO2 and C2H3 does not adversely affect the reaction system, indicating that the trace amount of acetylene in the raw material ethylene has a weak impact on the vinyl acetate reaction system.