CS263187B1 - 8pA " preparation of D-mannose - Google Patents

Abstract

The purpose of the method for preparing D-mannose is to improve the method for preparing D-mannose. The stated purpose is achieved by epimerizing D-glucose under the catalytic effect of molybdate ions at a weight ratio of D-glucose and water of 10:1 to 4 and heating at a temperature of 90 to 125 °C for 20 to 40 minutes. The method for preparing D-mannose has applications in the chemistry and biochemistry of carbohydrates.

Description

The present invention relates to a process for the preparation of D-mannose.

The preparation of D-mannose was based on the hydrolysis of natural material containing significant amounts of mannan such as shells of palm fruits (Phytelephas maerocarpa), seaweed (Phophyra umbilicas), feed yeast (Candida utilis), various yeast strains of the genus Saccharomyces and also bacterial polysaccharides (Salmonella) ). The disadvantage of these methods for the preparation of D-mannose is that the hydrolysis of natural materials results in the formation, mixture of other monosaccharides, oligosaccharides, amino acids and a variety of other organic and inorganic substances. Isolation of D-mannose is not easy from this mixture. D-glucose dimerization catalyzed by molybdenum ions is preferred for the preparation of D-mannose. In this method of preparing D-mannose, 15 to 30 wt. an aqueous solution of D-glucose was heated at 70 to 100 ° C for 5 to 10 hours under the catalytic effect of molybdenum ions, to obtain an equilibrium mixture of D-glucose and D-mannose in a mass of 1 wt. ratio 3: 1 (U.S. Pat. No. 149,051). A disadvantage of this method of epimerization is that the reaction time is too large and the aqueous solutions need to be inflated to recover some of the D-glucose.

These disadvantages are substantially eliminated by the proposed process for the preparation of D-mannose, which consists in the fact that the aqueous solution of D-glucose is epimerized under the catalytic action of molybdate ions at a weight ratio of D-glucose to water of 10: 1 to 4 at 90 to 125 ° C for 20 to 40 minutes.

An advantage of the proposed process for the preparation of D-mannose is that it greatly simplifies the process for the preparation of D-mannose by not doing so. ^{It is} necessary to thicken the solutions by reducing the reaction time and, as a result of the work with concentrated solutions, to make more efficient use of undemanding technological equipment.

Example 1

A mixture of 198 g of D-glycose monohydrate, 1.2 ml of 99% k.wt. of acetic acid and 1.25 g of ammonium molybdate (10: 1 weight ratio of D-glycose to water) was heated at 125 ° C for 40 minutes. After cooling to 70 [deg.] C., 100 ml of methanol are added to the reaction mixture and, after stirring, 100 ml of 96 wt. ethanol. 100 mg of crystalline D-glucose is then added to the solution and the mixture is left to crystallize at 23 ° C for 48 hours. The precipitated D-glucose monohydrate (81 g) was filtered off, washed with a mixture of methanol and 96% wt. ethanol in a 1: 1 by volume ratio, and the filtrate was treated with this mixture. alcohol to make up to 650 ml volume. Aniline (80 ml) was added to the solution and allowed to stand at 23 ° C for 24 hours after stirring. Crystalline N-phenyl-D-mannose amine (61 g) was filtered off and washed with a mixture of alcohols. A mixture of 61 g of N-phenyl-D-mannoslamine, 300 ml of sulfonated ion exchanger (Ostion KS 0 210) and 200 ml of water was stirred at 40 ° C for 4 hours. The ion exchanger is filtered off, washed five times with 100 ml of water and the filtrate is concentrated to give 42 g of D-mannose. By this process, 41 wt. % of D-glucose monohydrate to obtain 23.5 wt. D-mannose calculated on D-glucose and D-glucose, respectively. 39.5 wt. D-mannose due to regenerated D-glucose.

Example 2

Proceed as. in Example 1 except that 10 ml of water (D-glucose / water 10: 1.6 weight ratio) was added and the mixture was heated at 120 ° C for 30 minutes. 79 g (i.e. 40% by weight) of the monohydrate is recovered. % of D-glucose and obtains 42.5 g of D-mannose (i.e. 23.5 9 masses calculated on D-glucose).

Example 3

The procedure is as in Example 1, except that 10 ml of water (D-glucose: water 10: 2.1 weight ratio) are added and the mixture is heated at 120 ° C for 20 minutes. 75 g (i.e., 38% by weight) of D-glucose monohydrate are recovered to obtain 44 g of D-mannose (i.e., 24.5% by weight calculated on D-glucose).

Example 4

The procedure is as in Example 1, except that 20 ml of water (weight ratio D-glucose and water 10: 2.1) are added 1.3 g of molybdic acid instead of acetic acid and ammonium molybdate and the mixture is heated at 120 °. C for 20 minutes. 69.5 g (i.e. 35% by weight) of D-glucose monohydrate are recovered and 43 g of D-mannose (i.e. 24% by weight, calculated on D-glucose) are recovered.

Example 5

The procedure is as in Example 1, except that 20 ml of water (D-glucose / water ratio 10: 2.1 by weight) and 2.5 g of ammonium molybdate are added and the mixture is heated at 90 ° C for 40 minutes. 77 g (i.e., 39% by weight) of D-glucose monohydrate are recovered to give 42 g of D-mannose (i.e., 23.5% by weight calculated on D-glucose).

Example 6

The procedure was as in Example 1 except that 30 ml of water (D-glucose / water 10: 2.6 weight ratio) was added and the mixture was heated at 115 ° C for 25 minutes. 55.5 g (i.e., 28% by weight) of D-glucose monohydrate are regenerated to obtain 44.5 g of D-mannose (i.e., 24.5% by weight calculated on D-glucose).

Example 7

The procedure is as in Example 1 except that 30 ml of water (D-glucose / water 10: 2.6 weight ratio) are added and the mixture is heated at 90 ° C for 40 minutes. 57.5 g (i.e., 29% by weight) of D-glucose monohydrate are recovered to obtain 42.5 g of D-mannose (i.e., 23.5% by weight calculated on D-glucose).

Example 8

The procedure is as in Example 1, except that 35 ml of water (D-glucose / water 10: 3 weight ratio) is added and the mixture is heated at 110 ° C for 30 minutes. % D-glucose monohydrate to give 45 g of D-mannose (ie 25% by weight calculated on D glucose).

Example 9

The procedure is as in Example 1 except that 35 ml of water (weight ratio D-glucose and water (weight ratio D-glucose and water 10: 3) are added and the mixture is heated at 90 ° C for 40 minutes. and 45.5 g (i.e. 23% by weight) of D-glucose monohydrate to obtain 44 g of D-mannose (i.e. 24.5% by weight calculated on D-glucose).

Example 10

The procedure is as in Example 1, except that 55 ml of water (D-glucose / water 10: 4 weight ratio) are added and the mixture is heated at 105 ° C for 35 minutes. 20 g (i.e., 10% by weight) of D-glucose monohydrate is recovered to yield 46 g of D-mannose (i.e., 25.5% by weight calculated on D-glucose).

Example 11

The procedure is as in Example 1 except that 55 ml of water (D-glucose / water 10: 4 weight ratio) is added and the mes is heated at 90 ° C for 40 minutes. 18 g (ie 9% by weight) are regenerated. D-glucose monohydrate to give 45 g of D-mannose (i.e. 25% by weight calculated on D-glucose).

The invention may find use in organic chemistry in the preparation of D-mannose having utility in biochemistry.

Claims (1)

The invention may find use in organic chemistry for the preparation of D-mannose, which has a biochemical utility. OBJECT OF THE INVENTION A process for preparing D-mannose by epimerizing D-glucose in an acidic aqueous environment under the catalytic effect of molybdenum ions, characterized in that an aqueous solution of D-glucose with epimerizing molybdate ions at a D-glucose-water weight ratio of 10: 1 to 4 is heating at 90 to 125 ° C for 20 to 40 minutes. Severografia, n. P., MOST Price 2,40 Kcs