Papers by Author: Chang Hai Du

Abstract: KH₂PO₄-WO₃/γ-Al₂O₃ solid acid catalyst was prepared by the method of impregnation. According to the lactic acid dehydration production of acrylic acid reaction, some parameters including the load of WO₃ on γ-Al₂O₃, the calcination temperature, the reaction temperature and lactic acid concentration were investigated. The results show that the conversion of lactic acid was 92%, and the selectivity of acrylic acid was 29% under the optimized preparation conditions.

Abstract: The one-step synthesis of methyl isobutyl ketone from acetone (MIBK) and H₂ in liquid phase was studied over Ni-zirconia catalyst prepared by precipitation. The performances of Ni/ZrO₂ catalysts were evaluated by the conversion of acetone and the selectivity of MIBK. The effect of different preparation conditions such as aging temperature, calcination temperature, nickel content and reduction temperature was investigated. The results showed that high acetone conversions of up to 33% and MIBK selectivities of up to 85% were recorded at a nickel content of 13.0 wt % and the reduction temperature of 400°C.

Abstract: A novel solid base catalyst, structured MgO/Al₂O₃-Al catalyst packing, was prepared by supporting MgO onto a thin film of alumina that was formed by anodic oxidation of high purity aluminium foils. Some preparation parameters including the molar ratio of Mg(NO₃)₂•6H₂O to CH₃(CH₂)₁₆COOH, the aging time, the calcination temperature and time were investigated by using the catalyst for the condensation of acetone to diacetone alcohol. Each of those factors had some influence on the catalyst activity and an optimum value was obtained. The conversion of acetone was 20.2%, and the selectivity to diacetone alcohol was 100% under the optimized preparation conditions.

Abstract: The tungsten carbide catalysts supported on carbon nanotubes were prepared by the temperature-programmed reduction, and there were used as catalysts for the hydrogenation of cellulose. The optimum synthesis and reactive conditions were investigated. The results show that the WC loading was 40%, the catalyst calcination temperature was 773K, the reduction temperature was 1073K. The conversion rate of cellulose could reach 84.5%, and the yield of sorbitol was 45.9%. The WC/CNTs catalysts show high catalytic activities and higher selectivity towards sorbitol in crystal cellulose hydrogenation.

Abstract: The nanoalloy NiCoB and NiCoB/SiO2 catalysts were prepared by an incipient impregnation-chemical reduction method with NaBH4. They were characterized and examined for their catalysis in the hydrogenation of furfural to furfural alcohol. NiCoB and NiCoB/SiO₂ catalysts were characterized by XRD as amorphous structure. The amorphous NiCoB/SiO₂ catalyst was active in the hydrogenation of furfural, and it was significantly more active than NiB, CoB and NiCoB.

Abstract: The Co-promoted Ni-B amorphous nanoalloy catalysts were prepared by the chemical reduction of the aqueous solution containing nickel acetate and cobalt acetate with NaBH4 at room temperature and characterized by BET, XRD and DSC. They were used as catalysts for the liquid phase hydrogenation of furfural to furfural alcohol in alcohol at 353 K under 2.0 MPa of hydrogen. Ni-Co-B catalyst was characterized by XRD as amorphous structure. It was active in the hydrogenation of furfural, and it was significantly more active than Ni-B and Co-B. The optimal Co/ ( Co+Ni ) mole ratio in Ni-Co-B was 0.5.

Abstract: The degradation reaction of cellulose under the condition of microwave irradiation in an acidic aqueous medium including H2O2 has been investigated. The main factors, the solution acidity, reaction temperature and time, can have an effect on the cellulose degradation. The cellulose oxidative degradable polymerization was associated mainly with the action of releasing from H₂O₂. The scheme reflecting the main pathways of cellulose degradation in the reaction system of HCl/ H₂O₂ is proposed. A comparative study was investigated to evaluate the effects of microwave and conventional heating on cellulose degradation.