Production process of 2-keto-L-gulonic acid methyl ester

Abstract

The invention discloses a method for continuously producing 2-keto-L-gulonic acid methyl ester by taking 2-keto-L-gulonic acid as a raw material. A plurality of heat exchangers are connected in seriesto form a feeding heat exchanger; the back of the feeding heat exchanger is connected to a tubular reactor to form an esterification reaction device; a material outlet of the tubular reactor is connected to a thermal medium inlet of a primary heat exchanger formed by combining the first M heat exchangers of the feeding heat exchanger; a thermal medium outlet of the primary heat exchanger of the feeding heat exchanger is used as a discharging port of equipment for producing the 2-keto-L-gulonic acid methyl ester; and a secondary heat exchanger formed by combining the last N heat exchangers ofthe feeding heat exchanger adopts an external heat source. The production method comprises the following steps: blending, heating and continuous esterifying. The method has the beneficial effects that: the reaction time is remarkably shortened, the energy consumption is reduced, the workload of workers is reduced, the use amount of sulfuric acid is remarkably reduced, byproducts are reduced, the product quality is further improved, the use amount of conversion reaction alkali can be further reduced, the production cost can be further reduced, and the like.

Description

technical field [0001] The invention relates to a production process of 2-keto-L-gulonic acid methyl ester, in particular to a method for continuously producing 2-keto-L-gulonic acid methyl ester with 2-keto-L-gulonic acid as raw material The invention belongs to the technical field of vitamin C preparation. Background technique [0002] Vitamin C, also known as L-ascorbic acid, is a common raw material, which can be used to prevent and treat diseases. Diseases such as mental depression can also be used in a large amount in the food industry as fortifiers and antioxidants. [0003] The production method of vitamin C mainly adopts two-step fermentation to prepare gulong acid, and then produces vitamin C through chemical transformation. At present, the current conversion process in China is mainly an alkali conversion process, that is, 2-keto-L-gulonic acid and methanol under the action of sulfuric acid to generate 2-keto-L-gulonic acid methyl ester, and then add NaHCO 3 or...

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Problems solved by technology

CN101735183A discloses a method for synthesizing vitamin C sodium salt. Gulonic acid and methanol solution are mixed according to the ratio of mass volume ratio of 1:3 to 5, heated and dissolved, followed by granular activated carbon column for decolorization and cationic resin column for impurity removal. , dry filter to remove water; the treatment solution is heated to 40-60°C through the resin column to circulate the esterification reaction; the esterification solution is then converted to obtain vitamin C sodium salt, although compared with the traditional esterification reaction, it is replaced by resin Concentrated sulfuric acid is used as a catalyst, and there is no sodium sulfate residue in the crude Vc-Na produced, and the yield is high, but the process increases, the operation is cumbersome, and it takes a long time

[0004] The preparation of 2-keto-L-gulonic acid methyl ester in the above vitamin C production process belongs to intermittent production process, normal pressure reaction, long reaction time, Generally more than 3h, the production efficiency is low, and the traditional 2-keto-L-gulonic acid methyl ester preparation process uses a large amount of concentrated sulfuric acid, and the mass volume ratio of the concentrated sulfuric acid consumption to 2-keto-L-gulonic acid is 0.027 The above not only increases the production cost, but also affects the quality of the finished product; in addition, the production equipment occupies a large area and the labor intensity of the workers is high, which is also one of the problems to be solved in the existing 2-keto-L-gulonic acid methyl ester production process

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