Study On Liquefaction Of Cellulose With Catalyst Of Solid Acid In Water

With the declining petroleum resources and rising oil prices, it is necessary to develop alternative ways to fulfill the energy needs of our industrialized society. Biomass is the only practical source of renewable liquid fuel. Conversion of biomass through liquefaction to liquid fuel will relieve the shortage of energy, reduce the pollution of atmosphere and improve the quality of environment. Biomass direct liquefaction is an effective method to use biomass in large scale. Catalysts play an important role in the biomass liquefaction.In this thesis the cellulose, which is very rich in the nature, was chosed as raw materials. We prepared a series of Fe-based catalyst and a series of Si-MCM-41-based molecular sieve catalyst with hydrothermal synthesis and immersion respectively. The liquefaction runs were performed in water phase using hydrothermal method.The liquefaction results showed that, in the series of Fe-based catalyst, the ClO₄^-/Fe₂O₃-La₂O₃-ZrO₂ catalyst has higher catalytic activity than others. Under the optimum liquefaction reaction conditions: ClO₄^-/Fe₂O₃-La₂O₃-ZrO₂ was as catalyst, ratio of solvent to raw material was 30:1 (water/cellulose), catalyst dosage was 4 wt.%, reaction temperature was 250℃and reaction holding time was 1.5h, the liquefaction yield was 74.3%. In the series of Si-MCM-41-based molecular sieve catalysts, the ZrO₂/Si-MCM-41 and ClO₄^-/ZrO₂-Si-MCM-41 catalysts both have good catalytic activity. And they have the some optimum liquefaction reaction conditions: catalyst dosage 4 wt.%, reaction temperature 250℃, reaction holding time 0.5h and ratio of water to cellulose 50:1. The liquefaction yields of them were 95.2% and 94.62% respectively.The test results indicted that the solid catalysts can be repeated use for many times and keep high activity.The catalysts were characterized by FT-IR, XRD, NH3-TPD and specific surface determination. The results of GC showed that the gaseous products were H₂, CO, CH4, O₂ and CO₂. The results of GC-MS showed that the major products in the liquefaction reaction conditons were 5-(hydroxymethyl)-2-Furancarboxaldehyde, 4-oxo-Pentanoic acid, nonyl-Cyclopropane. 1-isopentyl-2,4,5-trimethyl-Benzene, 3-Hydroxy-4-methoxycinnamic acid and 1-(3-Methylbutyl)-2,3,4-trimethylbenzene.