SU1268561A1 - Method of producing aqueous solutions of polyols - Google Patents

Abstract

The invention relates to the production technology of polyhydric alcohols, specifically to the method of obtaining aqueous solutions of polyols (lUiy - sor bit, xylitol, widely used for medical and food gaps. Improving the quality and yield of the target product is achieved by hydrogenating monosaccharide aqueous solutions in the presence of urea. aqueous solutions of the corresponding monosaccharides under pressure on the catalyst - nickel Pei not in the presence of 0.05-5 g / l of urea at a temperature of 110-130 ° C. do not contain nickel ions and do not require additional purification. Table 1. IND.

Description

The invention relates to a technology for the production of polyhydric alcohols, and in particular to methods for producing aqueous solutions of polyols - sorbitol, xylitol, widely used for medical and food purposes.

The aim of the invention is to improve the quality and yield of the target product.

The goal is achieved by conducting a guide. of aqueous monosugar solutions on Raney nickel in the presence of 0.05-5 g / l urea, resulting in solutions of polyols that do not contain nickel ions and do not require ** subsequent purification.

Example 1. 340 ml of a 50% aqueous glucose solution (density 1.22 g / cm ¹ , glucose content 210 g) with a urea concentration of 2 g / l and a pH of 6.0 are loaded into a 0.5 l intensive mixing reactor 10 g of catalyst - Raney nickel (about 57, by weight of glucose). Hydrogenation is carried out at 120 "C and a hydrogen pressure of 6.0 MPa for

1.5 hours. After the completion of hydrogenation, the reaction product (technical sorbitol solution) is discharged from the reactor and filtered off from the catalyst. 338 ml of a 50 £ solution of sorbitol (loss of sorbitol solution during filtration of 0.5 ^) with residual glucose content are obtained. 0.05 I, the pH of the resulting solution is 5.8 u, no nickel, Examples 2-6. Analogously to example 1, hydrogenation of solutions of other sugars is carried out.

The process parameters and characteristics of the solutions of the obtained polyols are presented in the table.

Examples 5 and 6 demonstrate the absence of a positive effect outside the specified range of urea concentrations.

Claims (1)

The invention relates to a technology for the production of polyatomic alcohols, and specifically to methods for producing aqueous solutions of popiols — sorbitol, xylitol, widely used for medical and food purposes. The aim of the invention is to improve the quality and yield of the target product. The goal is achieved by conducting the hydrogenation of aqueous solutions of monosaccharides on Rene nickel in the presence of 0.05–5 g / l of urea, as a result of which solutions of polyols are obtained that do not contain nickel ions and do not require further purification. Example 1. 340 ml of a 50% aqueous glucose solution (density 1.22 g / cm, glucose 210 g) with a urea concentration of 2 g / l and pH 6.0 and 10 are charged to a 0.5 liter intensive mixing reactor. g catalyst - Rene nickel (about 5% by weight of glucose). The hydrogenation is carried out at a hydrogen pressure and 6.0 MPa for 1.5 hours. After the hydrogenation of the reaction product is completed (sorbitol technical solution), it is discharged from the reactor and filtered from the catalyst. 338 ml of a 50% sorbitol solution is obtained (loss of sorbitol solution at. filtration 0.5%) with a residual glucose content of 0.05%, the pH of the resulting solution is 5.8 units, nickel is absent, and prym ary 2-6. Analogously to example 1, the solutions of other sugars are hydrogenated. The process parameters and characteristics of the solutions obtained polyols are presented in the table. Examples 5 and 6 demonstrate the absence of a positive effect outside the specified concentration range of urea. The method of obtaining aqueous solutions of polyols by hydrogenation of aqueous solutions of the corresponding monosaccharides in the presence of a catalyst — Rene nickel under pressure at elevated temperature, characterized in that, in order to improve the quality and yield of the target product, the process is carried out in the presence of urea taken in an amount of 0 05-5 g / l solution, at a temperature MO-PO C.