Stereochemistry of the hydrogenation of cresol catalyzed by zeolite-supported polyvinyl alcohol amino acid platinum complex

Liquid-phase hydrogenation of isomeric cresol was investigated by zeolite-s upported polyvinyl alcohol-amino acid-platinum complex catalyst under mild conditions (50 degrees C, 1 atm). The catalyst was found to be very active and stable in the reaction. The initial rates for the hydrogenation of thre e isomeric cresols decreased in the following order m-cresol > o-cresol > p -cresol. Transmethylcyclohexanol is the most favored product for each of th e three cresols in cyclohexane solvent. The yields and the cis/trans ratios of the end products were affected by the solvents and amino acids selected . The catalyst can be recycled for more than three times in the hydrogenati on reactions without appreciable loss in activity. (C) 1999 John Wiley & So ns, Ltd.