MOLECULAR MECHANISMS IN THE CYCLOTRIMERIZATION OF ACETYLENE TO BENZENE ON PALLADIUM(III).

Article abstract of DOI:10.1021/j100316a051

Multiplexed temperature programmed reaction measurements have been used to examine mechanistic details of the acetylene yields benzene reaction on Pd(111). Results obtained from (C//2H//2 plus C//2D//2) experiments are in quantitative accord with a nondissociative reaction pathway; H/D scrambling in the reactants is not of significance, but at higher temperatures some H/D scrambling is observed between product molecules. The effects of surface crowding by unreacted acetylene on the binding and conformation of the benzene product are investigated, and it is shown that all benzene desorption is the result of the same initial reactive events. (C//2D//2 plus C//6H//6) data demonstrate that benzene desorption is not reaction-rate limited, consistent with the above conclusion.