Study On Catalytic Conversion Of Biomass-based Carbonyl Compounds In Aqueous Medium And Their Mechanism

The industrialization and modernization of the society mainly depend on the development and use of fossil fuels.In recent years,biomass as an important renewable resource to replace the fossil fuels has been paid more and more attention because of its abundant resources,carbon neutral,low pollution and so on.Many efficient methods for the conversion of biomass to high value-added chemicals and fuels have been reported.However,there are still some disadvantages in traditional methods for biomass conversion,such as high pollution,high cost and low efficiency etc.Therefore,it is of great significance to develop new methods for biomass conversion.Herein,the biomass and derivatives as raw materials were efficient converted to high value-added products in aqueous medium.These methods provide a new way of thinking for the future development of biomass resources.In the second chapter,the conversion of dimethyl phthalate to phenyl phthalide was studied by using cheap metal as reducing agent and common transition metal and metal oxide as catalyst.The optimum reaction conditions were determined by examining the effects of various parameters such as the amount of catalyst and reducing agent,reaction temperature,time and pressure on the reaction etc.The results found that the yield of phthalide reached 85% at 250 oC,2 h and 25% water filling when using 5 mmol Cu O as catalyst and 25 mmol Zn as reducing agent.At the same time,this method could also be used to convert the maleic acid dimethyl ester to ?-butyrolactone under hydrothermal conditions,and the yield was 11%.The mechanism study found that in situ formed the Cu was real catalyst whereas Cu O was a pre-catalyst for the transformation.In situ formed the Cu could be reused four times without the lose of its activity.The reaction pathway of dimethyl phthalate to phthalide under hydrothermal conditions was preliminarily proposed based on the findings of the study.The third chapter studies the direct conversion of ethylene ethylene as raw material to ethylene glycol without the addition of any catalysts and additives under hydrothermal condition.The optimum reaction conditions were determined by investigating the influence of various parameters such as catalyst,reaction temperature,time and pressure on the reaction etc.The maximum yield was 99% yield of ethylene glycol was obtained at 250 oC for 2 h with 25% water filling and 0.85 mmol ethylene carbonate without catalyst and reducing agent.At the same time,the propylene carbonate and butylene carbonate could also be converted to 1,2-propanediol and 1,2-butanediol by this method and yields of 59% and 62% were obtained respectively.Based on the results obtained,the possible reaction mechanism was provided.In the fourth chapter,the efficient conversion of succinic anhydride to succinimide was reported over nanoporous nickel catalysts in water.It was found that nanoporous nickel catalyst exhibited excellent catalytic activity for the reaction and the highest succinimide yield of 95% was achieved with succinic anhydride 0.4 mmol and ammonia water 120 ?L at 100 oC for 4 h in water in the presence of 5 mg Ni NPore.In addition,reusability of Ni NPore catalyst was investigated,the result indicated that Ni NPore still maintain high catalytic activity after three recycle times.At the same time,this method was used to convert glutaric anhydride to glutarimide and gave a 78% yield.The reaction pathway of succinic anhydride conversion over Ni NPore was also discussed.