SU559926A1 - The method of obtaining mannitol and sorbitol - Google Patents

Description

(54) METHOD FOR MAKING MANNITE AND SORBIT

one

This invention relates to an improved method for producing mannitol n sorbitol, which are widely used in the food and medical industry.

A known method of producing mannitol and sorbitol by inverting an aqueous solution of sucrose with a content of 25-75% solids at a pH of 1-2 and a temperature of 45-90 ° C, followed by hydrogenation of the resulting solution at pH 6-8, pressure 70-140 atm and 140-170 ° C on a suspended nickel catalyst. The catalyst is filtered off, the filtrate is cooled and purified noHHTaiMH. The purification solution is evaporated and the mannitol is separated by crystallization from aqueous alcohol solutions, and the sorbitol remains in the mother liquor.

The known method has a number of disadvantages, the main ones of which are: mandatory use of pure sucrose as the starting carbohydrate raw material; carrying out the process of hydrogenation of concentrated solutions at a temperature of 140-170 ° C leads to the decomposition of hexites with the formation of hydrogenolysis by-products; isolation of the target product from aqueous-alcoholic solutions complicates the technology of its i-ray, since it requires the introduction of the regeneration stage of the Siirt.

The aim of the invention is to improve the process technology.

For this, but the proposed method uses sugar raw material as a carbohydrate raw material, the solution of which is inverted in the presence of 3-5% activated carbon or 8-10% collactivite and displacement, followed by hydrogenation of the inverse solution and the steady-state silviolet Ni-A1-Ti catalyst at 125 -135 ° C and by heating the purified solution to 73-76%.

The desired product is isolated by crystallization from an aqueous solution under the following cooling mode: 5 deg / h for 2–3 h, then 3 deg / h for 2–3 h and then 1-2 deg / h until the end of cooling.

Claims (2)

The method is carried out as follows. A solution of raw sugar (20–25%) with a pI of 1.8–2.0 is inverted into 3-5% activated carbon or 8–10% collactivitis at 80–90 ° C for 30–35 min. The filtered inverse solution with the degree of inversion of 95-96% is hydrogenated for 30-45 minutes on a Ni-AI-Ti stationary alloy catalizer with a temperature of 7.5-8.5, a temperature of 125-135 C and a pressure of 100-110 atm. The resulting solution, containing 24-25% mannitol and 74-75% sorbitol, is purified by ion exchangers and vaporized to a dry matter concentration of 73- 76%. From the condensed solution at pH 3.8-4.0, when moving and cooling, crystallization is preferably carried out according to the following mode: the first 2-3 hours the temperature is reduced by 5 degrees / hour, then 2-3 hours by 3 degrees / hour, and then to 20-25 ° С with a speed of 1-2 degrees / h. The resulting crystals contain 70-75% mannitol and 25-30% sorbitol, 93-94% sorbitol remains in the mother liquor with a solids content of 69-72%. Pure mannitol with a melting point of 166-169 ° C is recovered by repeated recrystallization. Example. An aqueous solution of raw cane sugar with a concentration of 23.1% and a color of 69 °. The strainer is inverted with stirring at a pH of 1.8-1.9 and a temperature of 86-30 minutes in the presence of 3.9% active charcoal. The suspension is then filtered and get an inverse solution with a purity of 97.5% and chromaticity 2-2.5 of Stammer, containing 20.5% of dry matter. The resulting solution is neutralized with caustic soda to a pH of 8.0-8.2 and hydrogenated with a Ni-A1-Ti stationary catalyst at 128-134 ° C, with a pressure of 100-105 atm for 40 minutes. The resulting hydrour contains mannitol 24.1% and sorbitol 74.2% on the dry matter of the solution. Hydrogur, after cleaning it with ion exchangers according to the cathioite – ionite, is evaporated by vacuum to a dry matter content of 74.9%. The condensed solution is acidified with hydrochloric acid to a pH of 3.8-3.9 and cooled during displacement from 80.5 to 20 ° C at a rate of: 5 K / h to 2 h, then 3 K / h to 3 h and then 1.5 degrees / h until the end of cooling. At the end of the crystallization, the crystals are separated in a centrifuge. From 837 g of massecuite (628 g of dry substance), 180.5 g of crystals (in terms of dry substance) are obtained, containing 70.5% mannitol, 29.5% of sorbitol and 447.5 g (in terms of dry substance) of a sorbitol solution with mannitol content of 5.5%. By recrystallization of crystals from an aqueous solution, pure needle-like crystals of a main magnet are obtained with a melting point of 166.5-168 ° C. The invention claims 1. A method of producing mannitol and sorbitol from carbohydrate raw materials by inverting its solution with a pH of 1-2 and at a temperature of 45-90 ° C, hydrogenating the inverse solution on a nickel catalyst and a pH of 7.5-8.5 and a pressure of 100-110 atm , purification of the solution with ionites, evaporation and separation of the target product by crystallization, characterized in that, in order to simplify the process, raw sugar is used as a carbohydrate raw material, the solution of which is inverted in the presence of 3-5% activated carbon or 8-10% Collativitis transferring, followed by hydrogenation of the inverse solution on the stationary sylvium catalyst KCH-A1-Ti and 125-135 ° C and evaporation of the purified solution to 73-76%. 2. Method IO. I, O TL and H ayi with the fact that the target product is isolated by crystallization from an aqueous solution under the following cooling mode: 5 deg / h for 2-3 hours, then 3 deg / hours - 2-3 hours and then 1-2 degrees / h until the end of cooling. Sources of information taken into account by the expertise: 1. US Patent No. 2759024, cl. 260-635, 1965 (prototype).