|
Recent years, sugar alcohol as an important starch sugar derivative has been developed fast due to the evolution of starch sugar industry. It has been widely used and plays an important role in pharmaceutics, foods, chemical engineering industries, etc., because of its particular chemical and physical properties. Mannitol as an important kind of glucose derivatives has wide applications. In pharmaceutical industry, mannitol was used as diuretics and dehydrating agent. While in the chemical engineering industry, it can be used as raw material for synthetic resins and coatings. In daily chemical engineering industry, it can also be used as the raw material for cosmetics and toothpaste. In food industry, it is usually used as a sweetening agent for diabetic patients. So far, commonly used methods to prepare mannitol are extraction from seaweeds, synthesis method, fermentation method, and elsctrolytic reduction. In the thesis, a new technology was developed to produce mannitol by the double isomerization synthesis method.In this thesis, some important steps during the production of mannitol by the double isomerization synthesis method have been studied as follows. First we have done some researches on the parameters for the isomerizaion reactions of glucose, including the choice of catalyst and its amount in isomerization reactions, the concentration of glucose solution, the reaction temperature and time, the pH value, etc. Then we have studied the technological conditions for the decolorizing of glucose solution and ion exchange process after isomerization reactions, the catalytic hydrogenation process including the choice of catalyst and its amount used as well as the hydrogen pressure, the crystallization process of mannitol, and the chromatographic separation of mannitol and sorbitol from crystal liquor. Finally a new technology for producing mannitol with high yield and purity was successfully developed, and the yield can be higher than sixty percent by applying the optimized technological conditions in the production process.
|