Catalystic Conversion Of Glycerol To Lactic Acid Over Nano Cu/Au,Nano Cu/Pd,and Nano Pd/Nanographite Catalysts

Convering glycerol alternatives to traditional sugar fermentation technology to prepare lactic acid,not only solve the problem of world food shortages,fossil resource depletion,but also formed the renewable biomass glycerol high value utilization technology.Preparing high value-added lactic acid as raw materials research and development has good theoretical research value,at the same time they bring good environmental and economic significance.In this work,we designed three different structures of nanometer catalysts and nanometer copper gold,copper alloy catalyst palladium alloy catalyst and nanographite nano palladium catalyst,catalytic glycerin preparation of lactic acid in alkaline condition.The effects of reaction temperature,reaction time,concentration of sodium hydroxide,glycerin concentration,etc.The influence of reaction conditions on the catalytic reaction,analyzed the structure and catalytic activity of the catalyst structure-activity relationship.The research results are as follows.1.By wet chemical reduction method,the hexadecyl trimethyl ammonium bromide(CTAB)organic modifier induction was used prepare different Cu Au_x catalysts.Among Cu Au_x catalysts,the Cu Au2 showed the highest catalytic activity.When the reaction was carried out with the initial glycerol and Na OH concentrations of 2.0 and 2.2 mol L-1 at 200 o C for 2 h,the conversion of glycerol over the bimetallic Cu Au2 catalyst was 99.0% and the lactic acid selectivity of 93.8%.The carbon balance is 95.4%.2.By wet chemical reduction method,the PEG-6000 organic modifier induction was used prepare different Cu Pd_x catalysts.Among Cu Pd_x catalysts,the Cu Au2 showed the highest catalytic activity.When the reaction was carried out with the initial glycerol and Na OH concentrations of 2.0 and 2.2 mol L-1 at220 o C for 2 h,the conversion of glycerol over the bimetallic Cu Pd2 catalyst was 98.0% and the lactic acid selectivity of 95.3%.The carbon balance is97.3%.3.Nanographite was prepared by Hummer method,Pd_x/Nanographite catalysts were prepared by wet chemical reduction method with the PEG-6000 organic modifier.Among Pd_x/Nanographite catalysts,the Pd3/Nanographite showed the highest catalytic activity.When the reaction was carried out with the initial glycerol and Na OH concentrations of 2.0 and 2.2 mol L-1 at 220 o C for 2 h,the conversion of glycerol over Pd3/Nanographite catalyst brought a glycerol conversion of 83.4% and the lactic acid selectivity of 82.0%.The carbon balance is 89.9%.We found that the alloying trend over nano metal Cu/Au,Cu/Pd catalyst change single nanometer metal electronic distribution,which is advantageous to the catalytic conversion of glycerin preparation of lactic acid.Pd/nanographite showed higher than that of single catalytic activity of Pd nanoparticles,large specific surface area of nanographite carrier is advantageous to the nanoscale dispersion of Pd and improve the nano catalytic activity of Pd.