5-hydroxymethylfurfural Preparation From Hexose In Acetone/Water Solvent

5-Hydroxymethylfurfural(HMF)is a high-value bio-based platform chemical that can be prepared from hexoses such as glucose and fructose.However,the large-scale application of HMF is hindered by its high production costs due to low product yield and difficult separation.So in this study,the preparation and separation of HMF with inexpensive glucose as the raw material was studied,as well as the reaction mechanism.The work first determined that the cheaper glucose was used as raw material,and acetone/water,which was easy to separate,was selected as the solvent.Various factors that affect the glucose dehydration reaction were examined,including substrate concentration,Lewis acid catalyst type and concentration,proton acid catalyst concentration,reaction temperature,and composition of the mixed solvent.Moreover,the effect of inorganic salt addition on the reaction was also investigated.A one-way yield of HMF of 65%was achieved through reaction parameters optimization,which was higher than the value reported in the previous literature.Subsequently,the work further discussed the reaction mechanism.Through analyzing the distribution of substrate isomers,characterizing the structures of key substances(eg.reaction intermediates,products,by-products)and combining with theoretical calculation results,the work proposed a reliable reaction pathway from glucose to HMF.Next,it was inferred from the reaction pathway that the hexose dehydration would be strongly affected by the solvent,as well as the reaction efficiency and the product yield.As the most significant factor in the hexose dehydration reaction,acetone preferentially solvates the active groups of HMF,thus inhibiting the HMF degradation reaction,while water accelerates the hydrogen transfer process and achieves efficient conversion of glucose.Therefore,the acetone/water solvent achieved a balance among reaction efficiency,HMF yield,and separation difficulty,these major advantages make it a solvent with great potential for HMF production.Finally,the work considered the separation process to obtain high-purity HMF and proposed a conceptual process for the industrial production of HMF from glucose combined with the reaction process.The production cost distribution of HMF was obtained through fullprocess simulation and economic evaluation,with the purchase cost of glucose and product separation cost accounting for the largest proportion.These results provided a reference for further exploration of more efficient separation methods and determination of process optimization direction.