1,2-Propanediol co-produced in the dimethyl carbonate production is oversupplied in market. 1,2-Propanediol can also be facilely produced starting from glycerol, which is oversupplied in the biodiesel production. Catalytic conversion of low-valued 1,2-propanediol to high-valued and environmental benign lactic acid was investigated under mild reaction conditions over Au-Pd/Mg(OH)(2) catalysts in our present work. The Au-Pd/Mg(OH)(2) catalysts were prepared by the sol-immobilization method and characterized by XRD, SEM, HRTEM, UV-vis DRS, and O-2-TPD techniques. Small-sized Au and Pd nanoparticles were coalesced together to form secondary nanoparticles, which were well dispersed on the surfaces of Mg(OH)(2) nanoslices. The Au and Pd nanoparticles synergistically catalyzed the oxidation of 1,2-propanediol with O-2 to lactic acid in an alkaline solution. 'When the catalytic oxidation of 1,2-propanediol was carried out over Au0.75Pd0.25/Mg(OH)(2) catalyst at 60 degrees C for 240 min, the lactic acid selectivity of 88% was obtained at the 1,2-propanediol conversion of 97.5%. A power-function type reaction kinetic model well fitted the experimental data, r = dCp/dt = kC(P)(0.8)P(O2)(1.4)W(cat)(1.0). The reaction activation energy was 64 kJ mol(-1). (C) 2014 Elsevier B.V. All rights reserved.