Heterogeneous Catalytic Conversion Of Biomass-based Furfuraland Short-chain Alcohols Into High Value-added Chemicals

Biomass has abundant sources and is the only renewable carbon source.Among them,furfural and short chain alcohol are biomass platform molecules that can be prepared on a large scale and can prepare a series of high value-added chemicals.However,the currently reported catalytic system for the value-added reaction of furfural and alcohol still has some problems,such as easy deactivation of the catalyst,difficulty in controlling the by-reaction products and unclear catalytic conversion path.In order to solve the above problems,a series of highly active heterogeneous catalysts are designed and developed to convert furfural and short chain alcohols into high value-added chemicals.The specific research contents are as follows:（1）Titanosilicate mesoporous materials with adjustable textural properties for catalyzing the acetalization reaction of biomass derived furfural and n-propanolTiSi MMS prepared by sol-gel method were used as pure Lewis acid catalysts.The relationship between the composition,structure and catalytic performance of TiSi MMS was studied,the reaction conditions were screened,the catalytic active sites were verified by comparative experiments,and the possible catalytic reaction paths were proposed.The results show:The catalytic performance of TiSi-MM-1 prepared with TEOT as titanium source is better than that of TiSi-MM-2 prepared with PTOOD as titanium source.The sample with the largest Ticontent and the largest number of strongly acidic sites showed the best catalytic performance.Compared with the catalyst containing Br（?）nsted acid,using pure Lewis acid TiSi-MM as the catalyst can avoid the formation of black humic substances.After condition screening,when the amount of catalyst is 50 mg/1 mmol furfural,the highest conversion rate is 67.9%after reaction at 100℃for 2 hours.（2）Nano-Au anchored in organic base group-grafted silica aerogel:A durable and robust catalysts for green oxidative esterification of furfuralUsing SA-NH₂-x%Au as catalyst,study the relationship between the composition,structure and catalytic performance of SA-NH₂-x%Au,screen the reaction conditions,conduct continuous cycle reaction,determine the stability of the catalyst,design comparative experiments to verify the role of catalytic active sites,and put forward possible catalytic reaction paths.The results show that:SA-NH₂-10%Au has the best catalytic performance,and can achieve nearly 100%methyl furoate yield at 140℃ for 30 min.The yield of methyl furoate remained better than 98%in 7 cycles.Through the comparative experiment of adding p-benzoquinone and HCl to the reaction system,it is concluded that the activated oxygen species on the surface of Au and alkaline amino groups are indispensable to the optimal catalytic performance of the catalyst.（3）Reaction pathway and downstream product selectivity optimization of catalytic conversion of furfural and short-chain alcohols by TiO₂/exfoliated montmorillonite compositesUsing TiO₂/exfoliated montmorillonite as catalysts,the multi-step,and explore the relationship between the reaction conditions and the selectivity of each product,and reveal the possible catalytic conversion path.The results show that:10%Ti-H-MMT has the highest catalytic activity.The Ticontent in the catalyst increases,the acidity of the catalyst increases,especially the acidity of Br（?）nsted,and the yield of the main products furfuryl propyl ether and propyl levulinate is obviously improved.In addition,with the reduction of the amount of catalyst and the recycling of the catalyst,the acidic catalytic sites will be deactivated,which can reduce the number of acidic sites,thereby gradually reducing the yield of propyl levulinate and the yield of furfuryl propyl ether.The gradual increase indicates that the acidic catalytic site for the catalytic conversion of furfuryl alkyl ether to levulinate is absent or shielded.