The Application Research Of Fructose Dehydration Into 5-Hydroxymethylfurlural By Heteropolyacids As Catalyst

Since 20th Century, the fossil resources has been always supplied to product fuel and chemicals for the social need, which makes people more and more dependent on fossil resources. In the use of these materials, we have also made a lot of progress and breakthrough. With the development of technology, the population of the world has been continuously increasing and the quality of people’s life has been significantly improved, but this in turn would lead to accelerate the consumption of the fossil reserves. Due to the continuous consumption of fossil resources and the increasingly serious environmental problems, the development of renewable biomassre sources into valuable chemicals has attracted more and more attention. And the biomass resources fructose dehydration to produce a multifunctional platform compound 5-hydroxymethylfurfural (5-HMF), which is one of the hot topics to get people’s attention.5-hydroxymethyl furfural derivatives can be used as green fuel and extremely important value chemicals.Dehydration of fructose is generally carried out in acidic condition. So far, the main use of catalysts including Bronsted acid, such as inorganic acids and organic acids, as well as Lewis acid, such as the metal salt and metal oxides et al. However, in the process, there are still some problems, such as the reaction time is too long, the selective of 5-hydroxymethyl furfural is low, catalyst poisoning, and the corrosion of equipment, which greatly restricts the further application of them. In contrast, heteropolyacids (HPAs) is a good solid super acid catalyst. Because of its strong acidity, Keggin type polyoxometalates in many reactions have been shown high catalytic activity, such as hydrolysis, esterification, and saccharification et al. At the same time, there is almost no corrosion to equipment, and environment friendly. Therefore, this paper uses the heteropolyacids as the catalyst materials for the dehydration of fructose to 5-HMF. The main work is as follows:1. Our study is the first to put forward the catalyst system of H3PW12O40 and H4SiW1204o as catalyst, ionic liquid [BMIM]C1 as green solvent for the dehydration of fructose to 5-HMF preparation. The results show that, on the mild conditions which the temperature is 80℃ and reaction time is 5 min, both the product and selectivity of 5-HMF from fructose reached 99%. Recovery and reused the catalyst and solvent for at least 10 times without obvious decrease of catalytic activity. Therefore, this catalytic system is accord with the high efficiency, moderate, green and sustainable development;2. we develop herein a highly efficient and selective catalytic system of PW12/SiO2 for fructose conversion to 5-HMF, which shows highly efficient and selective dehydration of fructose to 5-HMF in DMSO with 97% HMF yield and 98% selectivity in the presence of the 9 wt% PW12/SiO2 catalyst at 120℃ in 60 min. The TOF of the catalytic system is as high as 576 h-1. The catalyst of PW12/SiO2 can be recovered and reused for at least ten times without obvious decrease of the reactivity. In addition, the scaled-up experiment by increasing the reaction volume from 5 mL to 250 mL shows excellent results of fructose dehydration using PW12/SiO2 as catalyst. As such, the reusability, high selectivity and efficiency of PW12/SiO2 suggest its potential for further applications as an environmental-benign and sustainable catalyst from catalysis and technology point of view.