Preparation Of Acid-base Catalyst For One-pot Catalytic Conversion Of Cellulose Into 5-Hydroxymethylfurfural

With growing concerns on global warming and decrease of fossil energy availability,the production of renewable chemicals and fuels has attracted worldwide interest.Biomass with the characteristics of rich resources,renewable and low pollution was considered to be one of the most promising energy alternatives.5-hydroxymethylfurfural（5-HMF）was identified as omnipotent value-added chemicals and high performance liquid fuels.Catalyst plays a vital role in the catalytic conversion of cellulose to HMF,as reaction rates,product yields and selectivity are also highly dependent on the catalyst characteristics.In order to improve the sustainability of one-step conversion of cellulose into HMF,enhance the HMF selectivity,increase the activity and durability of catalyst and easy separation from the reaction system,the development of novel catalytic systems is imminent.Due to the advantages of large specific surface area,high porosity,small corrosion to equipment and the advantages of product separation of porous solid catalyst,porous solid catalyst is a kind of ideal catalyst.This paper aims to improve the efficiency of the conversion of cellulose into HMF,and prepare three kinds of porous solid catalyst and study their properties roundly.Detailed contents are summarized as follows:（1）The preparation of acidic-basic bifunctional mesoporous catalysts for one-pot conversion of cellulose into 5-hydroxymethylfurfuralWith long chain alkyl trimethyl ammonium bromide（CTAB）as template,four ethyl orthosilicate（TEOS）as raw material,with NH4 F as catalyst,in alkaline conditions,six-party channel nano silica mesoporous materials（MSN）are prepared by hydrothermal method.Then,by modification method,respectively,sulfonic group（-SO3H）and amino group（-NH2）were grafted on inside and outside surface of MSN,namely the acid-base bifunctional mesoporous catalysts were synthesized.In order to investigate the role of acid and basic active sites in the catalytic synthesis of HMF in one step,mesoporous catalysts only contained acidic sites and mesoporous catalysts only contained basic sites were synthesized.In addition,the catalysts were applied inconversion of glucose and fructose into HMF.Finally,repetitiveness of the catalysts were discussed.（2）The preparation of acid-base bifunctional hierarchical pore catalyst for one-pot conversion of cellulose into 5-hydroxymethylfurfuralPorous polymers（PHs）was prepared by high internal phase emulsion（HIPEs）W/O template with a small amount of Hypermer 2296 as emulsifier,azodiisobutyronitrile（AIBN）as initiator,divinyl benzene（DVB）and glycidyl methacrylate（GMA）as monomers.Then,we integrated acid-base bifunctional mesoporous silica nanoparticles（MSNs-SO3H-NH2）with macroporous polymer foam by chemical method.After the sulfonating in concentrated sulfuric acid,the acid-base bifunctional hierarchical pore catalyst（SPHs@MSNs-SO3H-NH2）were prepared successfully.The catalyst was applied in the conversion of cellulose into value-added chemicals,as well as applied in catalytic glucose and fructose into HMF.（3）Facile synthesis of hierarchical pore catalysts with Br?nsted-Lewis acid sites for conversion of one-pot cellulose to 5-hydroxymethylfurfuralPropyl alcohol zirconium（Zr Pr）was grafted onto the surface of hydroxyl silicone template by the sol-gel process,then the sample was soaked in sulfuric acid solution for introduction of sulfonic acid group,after high temperature calcination,the sulfonated ZrO₂ nanometer materials with super acidic surface（SZs）were prepared.Then,SZs was applied as stabilized particles with a small amount of Tween85 to prepare for oil-in-water（O/W）Pickering HIPEs.After subsequent ion-exchanging process,Br?nsted acidic sites were located on the surface of hierarchical pore foam catalysts（HPFCs）.The resulting HPFCs with Br?nsted-Lewis acid sites was used in the reaction of one-step conversion cellulose,glucose and fructose into HMF,respectively.