Synthesis And Application Of Ionic Liquids In The Reeds Of Cellulose Hydrolysis

With the over-exploitation of petroleum-based resources,we will face the shortage of resources in future.Biomass,as a renewable raw material,can be an alternative to fossil fuel resources.If we can effectively convert biomass into fuels and chemicals,the dependence on fossil fuels will be reduced.It is important to develope and utilize the most abundant renewable resources in nature-cellulose for solving the energy crisis that humanity face.However,the characteristics of the molecular structure of cellulose,non-melting and difficult solubility limit its development and use.Cellulose is potential in large-scale preparation of5-hydroxymethyl furfural(5-HMF)which can replace fossil fuels,and whose degradation product 2,5-dimethyl furan(DMF)is a key and versatile intermediate in bio-fuel and petrochemical industry.It is considered as one of the most potential 12 kinds of platform molecules in the 21 st century by the US energy sector.Ionic liquids are emerging as green solvents and imidazole ionic liquids are currently the most ionic liquids reported in literature.But they also have many shortcomings such as high viscosity,difficult processing and recycling and so on.In this paper,We synthesized a series of pyridine ionic liquids,and explore the best conditions of preparing 5-HMF when add acid as catalysts to hydrolyze cellulose.First We got N-butylpyridinium bromide ionic liquid([BPy]+Br-)by one-step alkylation reaction,then prepared other pyridine ionic liquids by two methods.One way is to make the aqueous solution of [BPy]+Br-flow through the strong base anion exchange resin,then prepare N-butyl picolinate([BPy]+HCOO-)and N-butyl pyridine acetate([BPy]+Ac-)by reacting with the corresponding acid.The other way is to make a halogen ion liquids react with corresponding salts by using suitable amounts of acetone as a solvent.The reaction mixture was stirred at room temperature to prepare N-butyl pyridinium tetrafluoroborate[BPy]+BF4-and N-butyl pyridine nitrate [BPy]+NO3-.In the same condition,we can get most 5-HMF when adding [BPy]+Br-to hydrolyze reed cellulose.With [BPy]+Br-as solvent,we also designed six factors(catalysts,the amount of catalyst,the amount of water,the amount of hydrochloric acid,reaction temperature,reaction time)and five levels of different conditions orthogonal to discuss the effects on cellulose hydrolysis and the optimum conditions to get more yield of 5-HMF.The optimal hydrolysis reaction condition was: chromium chloride as a catalyst,an amount of 0.03 mmol,15 ?L of water,the reaction temperature 110 ?,time 3 h.Then with triethylenediamine and hexamethylenetetramine as raw material respectively,we used a two-step method to synthesize the two kinds of multi-sulfo group ionic liquids:[Bis-Bs-DABCO] [HSO4]2(Bis-double points;Bs-tert-butyl sulfonic acid group;DABCOTEDA)and [Q-Bs-HMA] [HSO4]4(Q-four times,Bs-tert-butyl sulfonic acid group,HMA-hexamethylenetetramine amine).Then the acid functional ionic liquids were also applied in cellulose hydrolysis.Under such condition,a higher yield of 5-HMF can be obtained in a short time.In [BPy]+Br-/ [Q-Bs-HMA] [HSO4]4 / CrCl3 catalytic system,the increase the yield of5-HMF increased by increasing the amount of CrCl3?...