Oxidation of glucose in suspensions of moderately hydrophobized palladium catalysts

In absorption with fast chemical reaction, the reaction occurs only in the liquid-side film at the interface whereas the gas concentration in the bulk of the liquid is about zero. The absorption might be more strongly enhanced if the catalyst concentration in the film was locally increased. For the oxidation of glucose to gluconic acid on suspended Pd/Al2O3 particles, particle adhesion at the gas–liquid interface was promoted by moderate hydrophobization with trichloromethylsilane (TCMS). The silanization had no significant effect on the catalyst activity studied under kinetic control. In the mass transfer controlled regime, enhancement of the absorption rate by the hydrophobized Pd/Al2O3 catalyst particles occurred at very low catalyst loadings. This can be attributed to locally higher catalyst concentration in the liquid film.