| Thiazole derivatives have been widely used in pesticide, pharmaceutical chemistry and other fields for its outstanding drug and biological activity. And, scientists have been paying close attention to study of new thiazole derivatives. Green chemistry, which whole process is environment-friendly from raw to products, has become a research hotspot and frontier. Recently, ionic liquid with its excellent physical and chemical properties, as a solvent or catalyst plays an important role in catalytic reactions and organic reactions.5-Hydroxymethyl furfural (HMF) as an important platform chemical compound has important applications in medicine, synthetic resin, bio-fuels additives and other fields. Chitosan, which is the second-largest renewable natural resources on the earth, has been widely used in functional materials, food industry, agriculture, textile industry and other fields. If it is used to transform into the energy platform chemicals; and will certainly have a significant economic and social benefits. In this study, besides synthesis of three novel thiazole derivatives, a green approach for the effective transformation of chitosan into HMF was provided and the mechanism of chitosan degradation in ionic liquids was studied. This study provides a basis for the transformation of chitosan into energy compound.This dissertation mainly focus on the study as follows:Firstly, thiazole derivatives are an important class of substance which have many physiological and drug activities. Three kinds of new thiazole compounds were synthesized via a set of reactions using 2-methyl-4H-pyrrolo[2,3-d]thiazole as the raw material. Thiazole derivatives enrich the type of thiazole and pharmaceutical intermediates and provide more choices for pharmaceutical intermediates.Secondly, solid acid catalysts have demonstrated excellent catalytic activity in the process of hydrolysis of carbohydrates. However, there are few reports for the conversion of chitosan to 5-HMF by solid acid catalysts. According to reports, a series of solid acids were prepared and applied to produce HMF from chitosan or chitin. From the experiment results, an efficient acidic silica gel SG/IL was discovered and its structure was confirmed based on TG/DTG, FTIR and XRD characterization. Moreover, solvents, reaction time and reaction temperature were optimized and the highest yield of HMF was obtained in water. As can be seen from the FTIR spectroscopies of solid residue, important functional groups were still present after the hydrothermal process.Thirdly, using Design-Expert 8.0 software, we conducted central composite experimental design and response surface regression analysis for the reaction condition of chitosan conversion into HMF with SG/IL catalyst. And then a linear fitting equation and the optimal reaction conditions were obtained. The optimal reaction conditions as follows:reaction time was 5.82 h, reaction temperature was 185.26℃, amount of catalyst was 3.3 g. Under the optimal reaction conditions, the HMF yields were obtained in 31.4 and 21 mol% from chitosan and chitin, respectively.Fourthly, water-soluble oligosaccharide molecule was confirmed in reaction solution by HPLC-MS. Furthermore, the reaction mechanism of chitosan converting into HMF was speculated. The mechanism is that chitosan is hydrolysised to water-soluble chitosan oligosaccharide and ring-opening isomerization at the end groups of oligosaccharide, glycosidic bond breaking to glucosamine and then via deamination, Keto-Enol isomerization and further dehydration to form HMF.
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