Catalytical Synthesis Of HMF And DMF Based On Biomass

With the increasing consumption of fossil fuels and the increasingly severe energy problems,enormous researches aimed to develop the biomass energy has undoubtedly provided new directions,new ideas and new ways to solve the current energy problems.This topic focuses on the use of biomass as a raw material,through the rational design of a variety of heterogeneous catalysts for high selectivity to obtain 5-hydroxymethylfurfural(HMF)and(DMF)two bio-based chemicals.In this paper,mainly started from fructose.firstly,we selected H-Beta molecular sieve as a catalyst for the dehydration of fructose into HMF.Optimizing the different silicon-aluminum ratio and exploring the optimal reaction conditions,we found that HMF was produced at low silicon-to-aluminum ratio.The rate reached the highest 83.4%;then,after the fuming silica gel was used as the carrier and loaded with different functional groups,the relationship between the infiltration property and the reactivity of the catalyst after the sulfonic acid group was supported was investigated.It was found that in the case of hydrophobic catalyst,highly yield of HMF was obtained.Aiming the highly selective production of 2,5-dimethylfuran(DMF)from fructose,a one-pot strategy and bifunctional catalysts with different surface wettability were specially designed.Given the low stability of the intermediate product,namely 5-hydroxylmethylfurfural(HMF)in the presence of acid and water,improved stability and efficient transformation into the target product is of clear significance and interest.The hydrophobic surface of the as-prepared catalyst assisted in rejecting water molecules and promoting the adsorptive property for the hydrogen donator,avoiding side-reactions and facilitating conversion of HMF into DMF.The hydrophobic catalyst Pd/PDVB-S-143 showed a high activity and good stability for producing DMF from fructose:a 94.2%yield was obtained at a mild temperature of 120℃ and no loss in activity was observed after 5 cycles.From the standpoint of green and sustainable chemistry,there may be three possible advantages.Firstly,HMF separation is avoided,reducing the amount of organic solvent and energy expenditure for purifying HMF;secondly,highly efficient production of DMF is realized under mild reaction conditions;finally,polymethylhydrosiloxane(PMHS)replaces the dangerous gas H2 as the hydrogen source,increasing the security of the whole process.Overall,this work demonstrates a successful paradigm for rational design and preparation of novel catalysts with both high activity and superior selectivity during biomass upgrading.