Investigation On Glucose To 5-hydroxymethylfurfural Catalyzed By Supported Aluminium Chloride

Chemical products, which prepared from non-renewable fossil resources such as petroleum, are facing threat of resource exhaustion. Biomass is the most likely alternative resources because of their widely and easily accessible.5-HMF, an important biological platform compound, can be transformed into many C-6 compounds with high energy density, which could be the potential alternates for petroleum. It plays an important effect on delaying the current energy crisis. In recent years, it is a hot spot in this research field that the dehydration of biomass including glucose, fructose and sucrose, starch and cellulose transformed into 5-HMF. In this thesis, AlCl3 loaded solid acid catalyst was designed for the dehydration of glucose to 5-HMF, which explored a green catalytic system for synthesis of 5-HMF. Reaction path of this reaction catalyzed by AlCl3 were studied by theoretical calculation method, which provided a new idea and direction for future research in this reaction.Here, an environmental friendly Lewis solid acid catalyst, activated carbon supported aluminum chloride (AC-AlCl3) was prepared. AC-AlCl3 can efficiently catalyze the dehydration of glucose to 5-HMF, and can be used repeatedly.5-HMF yield reached 34.1% after reacting 0.5 h at 160 ℃ in DMAC solvent in the molar ratio of glucose to AC-AlCl3 was 4%. Catalyst reused for 7 times without dramatically decrease of its activity. Furthermore, it could be recovered after a simple treatment. The research on active centers of the catalyst and deactivation reasons showed that AlCl3 was the active centers of AC-AlCl3, and both Al and Cl elements played catalytic roles in this reaction. Loss of chlorine was the main reason for catalyst deactivation, therefore the catalytic activity could recovered by washing with dilute hydrochloric acid.Bamboo charcoal sulfonic acid supported aluminum chloride (BC-AlCl3), which possesses Lewis acid and Bronsted acid centers, was prepared. The catalytic activity of BC-AlCl3 was lower than that of AC-AlCl3 in this reaction, and the possible reason was that the loaded aluminum chloride in BC-AlCl3 catalyst is less, and the efficient sulfonic acid centers would not give the expected effect. The possible reaction path of glucose dehydration to 5-hydroxymethylfurfural using aluminum chloride as the catalyst was investigated by DFT/B3LYP theoretical calculation method using Gaussian 09 software. Simulation results showed that glucose tended to isomerize to fructose first and then dehydrated to 5-HMF in the present of AlCl3, and the reaction need to be carried out under high temperature.