Study On Cellulose Decomposition And Synthesis Of 4-Oxopentanoic Acid Under MCM-41 Supported Bimetallic Catalyst

In this thesis MCM-41 molecular sieve was prepared by hydrothermal synthesis. The Ni-W or Ni-Mo supported bimetallic catalyst was prepared by the impregnation of a MCM-41 support with an aqueous solution of nickel nitrate and sodium tungstate, or nickel nitrate and ammonium molybdate respectively. Cellulose (cotton), as a raw material, was decomposed in water by using of supported bimetallic catalyst. The influences of catalyst amount and reaction time on the residue rate of cellulose or the yield of 4-oxopentanoic acid were investigated. The qualitative analysis of liquid products from cellulose conversion was carried out by GC-MS or HPLC.The catalysts were characterized by XRD, UV-Vis and specific surface determination.The results of test showed that the liquid components produced by Ni-W/MCM-41 or Ni-Mo/MCM-41 were different. The product by using the former catalyst was 4-oxopentanoic acid (main component) and 3-methyl-2-Butanol.While by using the latter catalyst the reaction would produce more complex oxygenated compound, in which the main compound was 1,2,3-Benzenetriol (25%) and fewer 4-oxopentanoic acid (9%).Under Ni-W/MCM-41 the influences of changing process condition on yield of 4-oxopentanoic acid were not always similar. For the residue rate of cellulose, the optimum technological conditions were as follows:the reaction temperature was 280℃, the amount of catalyst was 0.05g, the reaction time was 2h, the ratio of liquid to solid was 50:1,the lowest residue rate was 9.60%.For the yield of 4-oxopentanoic acid, the optimum technological conditions were:the reaction temperature was 250℃, the amount of catalyst was 0.05g, the reaction time was 2h, the liquid-solid ratio was 50:1,the highest yield of 4-oxopentanoic acid was 20.17%.By using Ni-Mo/MCM-41 catalyst, under the optimum technological conditions of the reaction temperature 250℃,the liquid-solid ratio 50:1,and reaction time 1h, the lowest residue rate was 7.50%.The optimum technological conditions to prepare 4-oxopentanoic acid were as follows:the amount of catalyst was 0.15g, the reaction time was 2h, the highest yield of 4-oxopentanoic acid was 17.69%. The characterization results of catalysts showed that in Ni-W/MCM-41 the Ni and W species deposited in the porous channel of molecular sieve. The metal elements Ni and W existed in the form of NiWO4, WO3,and octahedral Ni(Ni(O)).In Ni-Mo/MCM-41 the metal elements Ni was highly dispersed in the form of octahedral on the support.