Catalytic Conversion Of Cellulose Into 5-hydroxymethyylfurfural(HMF) In The Ionic Liquid

Diminishing fossil fuel reserves and growing concerns about global warming indicate that sustainable resources are needed in the near future. With advances in conversion technology, plentiful biomass resources have the potential to regain their central position as feedstocks for civilization, particularly as renewable carbon sources for transportation fuels and chemicals. Biomass is abundant, renewable, and is distributed widely in nature, which are promising alternatives for the sustainable supply of liquid fuels and valuable intermediates (such as alcohols, aldehydes, ketones, and carboxylic acids) to the chemical industry for production of drugs and polymeric materials. Utilization of biomass requires efficient methods to convert carbohydrates into a variety of chemical compounds. Cellulose is the most aboundant renewable carbon source for production of fuels and chemicals.5-Hydroxymethylfurfural (HMF) is a versatile biomass-derived platform compound that can be used to synthesize a broad range of chemicals currently derived from petroleum. It is clear that large scale, sustainable use of HMF will require cellulose biomass as feed. Such use necessarily involves depolymerization of cellulose to form glucose, the building unit of cellulose, followed by conversion of the glucose to HMF. Cellulose has a supramolecular structure of various chain-size, crystallinity, and complexity, it is the depolymerization process, which involves decrystallization followed by hydrolytic cleavage that has been the primary bottleneck limiting energy efficient and economical utilization of cellulosic biomass. In this thesis, we report a new pathway that enables cellulose depolymerization and glucose conversion to HMF in a single process under mild conditions.One-pot dehydration of cellulose into 5-hydroxymethyl-2-furldehyde (HMF) in the presence of acid(SO3H-functional ionic liquid and H-molecular sieve) and CrCl3 was investigated in detail. Ionic liquid 1-butyl-3-methylimidazolium (BmimCl) was used as the solvent of cellulose. The liquid products were analyzed by high performance liquid chromatography (HPLC). The influences of reaction temperature, reaction time and reactant ratio on the catalytic properties in the conversion of cellulose were studied. It was shown that cellulose as the feed is rapidly depolymerized and the resulting glucose is converted into HMF under mild reaction conditions. The results indicated that under optimized reaction conditions of T=130℃, n([(CH3)3N(CH2)4SO3H][HSO4]):n(CrCl3):n(Cellulose)= 6:4.5:100,the yields of HMF and total production were 41％and 51％,respectively；T=130℃,the ratio of H-ZSM-5 zeolite and cellulose 1:10,n(CrCl3):n(Cellulose)=3.0:100,the yields of HMF was 41％.