EFFECT OF PLATINUM PARTICLE-SIZE AND CATALYST SUPPORT ON THE PLATINUM-CATALYZED SELECTIVE OXIDATION OF CARBOHYDRATES

The effect of the platinum particle diameter and the catalyst support was investigated for the aqueous phase selective oxidation of methyl a lpha-D-glucopyranoside octyl alpha-D-glucopyranoside and alpha-cyclode xtrin with molecular oxygen. No platinum particle size effect was obse rved in the platinum particle diameter range of 1.4 to 3.0 nm. The str ucture-insensitivity is attributed to the high degree of surface cover age by oxygen. The rate of deactivation due to over-oxidation of the c atalyst increases to a small extent with decreasing platinum particle diameter. The effect of the catalyst support is much larger than the p latinum particle size effect. The turnover frequency for platinum on a ctivated carbon and carbon fibrils supported catalyst is 3-7 times hig her than for graphite as the catalyst support. The support effect is a ttributed to the hydrophilic character of the support.