Method for preparing D-mannose

Abstract

The invention discloses a method for preparing D-mannose. The method comprises the following steps of: epimerizing glucose to partially transform the glucose into mannose to obtain a mixed solution of the glucose and the mannose, separating the mixed solution for three times by a simulated moving bed to obtain C1 which is rich in a mannose component as well as A2, B2 and C2 which are rich in a glucose component, and desalting the C1, concentrating, crystallizing, centrifuging and drying to obtain high-purity D-mannose. The separated liquid which is obtained through first-time separation by the simulated moving bed and is rich in the glucose component is filtered by a membrane filtration device, then dialysate is epimerized, and the separated liquid B2 and the separated liquid C2 which are obtained through second-time separation and third-time separation by the simulated moving bed enter the simulated moving bed and are separated for the first time again. In the process, a membrane separation technology and a high-efficiency separation effect of the simulated moving bed are utilized, and a crystal product with the purity of over 99 percent is directly obtained in a way of the combination of cooling crystallization and organic solvent crystallization through one-step crystallization without a refinement link; and the process is simple and the product can be produced easily.

Description

technical field [0001] The invention relates to a method for preparing D-mannose. Background technique [0002] D-Mannose is a white powder crystal with α-type and β-type crystals. Soluble in water (250%), insoluble in ethanol (0.4%), insoluble in ether. D-Mannose is sweet, 0.6 times that of sucrose and 0.86 times that of glucose, with a slightly bitter aftertaste, reductive, and can be fermented by microorganisms. Mannose in nature mostly exists in the form of aggregation, for example, in the konjac of Araceae plants, called mannose oligosaccharides. Mannose can be used in food, medicine and other fields. Some research data in the United States show that mannose is a kind of sugar with special curative effect. It has good sterilization and anti-inflammatory functions, and it has a good auxiliary treatment effect on diabetes, obesity, constipation, high cholesterol and other diseases. [0003] In the prior art, crystalline D-mannose is mainly obtained by extraction metho...

AI Technical Summary

Problems solved by technology

However, there are many defects in the extraction method: the problem of environmental pollution in acid degradation, and the high cost of enzymatic degradation

This method can obtain high-purity crystalline D-mannose, but the solubility of mannose in water is 250g / g, and the crystallization of the water phase is difficult; two concentration processes are required before the crystallization of the water phase, which increases energy consumption costs; the crystallization process of the water phase It is necessary to control the cooling rate in the process, and the requirements for temperature control equipment are high; the crystallization lasts 60-100h, which is long in time and low in efficiency; the crude mannose obtained by aqueous phase crystallization needs to continue to be refined with absolute ethanol, and the process is cumbersome; and this process is in the process of separation and purification The gel polystyrene Ca type resin is used in the process, and the separation rate is less than 60%

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