Oxidation Kinetics of 1,2-Propanediol in the Presence of Pd and Pt Catalysts

摘要

1.25-5 wt% Pt/Al2O3, 1.25-5 wt% Pd/Al2O3, 1 wt% Pd/TiO2, 1-5 wt% Pd/TiO2-NF, 1.25 wt% Pt + 1.25 wt% Pd/Al_2O_3, 5 wt% Pt/SiO_2, and 5 wt% Pt/C catalysts were synthesised and tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that all catalysts were active in alkaline water solutions; lactic acid was obtained as the main product of the reaction. The conversion of 1,2-propandiol and the yield of lactic acid depended on the content of active metal in the catalysts. The most active for the oxidation of 1,2-propandiol were palladium-containing catalysts supported on TiO_2 nanofibers (Pd/TiO_2-NF). The highest 1,2-propanediol conversion (100 mol%) and lactic acid yield (96 mol%) were obtained using the 5 wt% Pd/TiO2-NF catalyst at the following oxidation parameters: c0(1,2-propanediol) = 0.3 mol/L, P(O_2) = 1 atm, n(1,2-propanediol)/n(Pd) = = 500 mol/mol, t = 60 °C, c0(NaOH) = 1.5 mol/L.