COMPETITIVE HYDROGENATION IN ALKENE-ALKYNE-DIENE SYSTEMS WITH PALLADIUM AND PLATINUM CATALYSTS

Competitive hydrogenation of alkene, alkyne and diene substrates (C-6- C-8) over palladium and platinum catalysts were studied at 20 degrees C and atmospheric pressure. Selectivities of these reactions were dete rmined and the substrates relative adsorption coefficients calculated. It was found that hydrogenations of alkynic and dienic substrates wer e preferred in alkyne-alkene and diene-alkene systems, respectively. I n these systems palladium catalyst selectivity was higher than selecti vity of the platinum catalyst, due to higher relative adsorption coeff icients of corresponding substrate couples on the palladium catalyst. (C) 1998 Elsevier Science B.V.