Method for preparing VC by ultrasonic induced crystallization on gulonic acid aqueous solution

Abstract

The invention relates to a method for preparing VC by ultrasonic induced crystallization on a gulonic acid aqueous solution. An ultrasonic field is loaded on the gulonic acid aqueous solution, gulonicacid is ultrasonically induced to be directly converted into VC crystals, the conversion speed and conversion ratio can be greatly increased, and the gulonic acid is directly induced to be convertedinto VC crystals. By an ultrasonic environment, the conditions that VC can be induced to make grain by seed crystals and the crystals are induced to grow, therefore, a small amount of VC crystals canbe added in the solution when the gulonic acid aqueous solution is evaporated to reach a grain making point, and thus, a process of accelerating induction of grain making is accelerated. The method does not comprises a technological process of converting VC salt from the gulonic acid (catalyzed by sulfuric acid) by methyl esterification and by lactonization under an alkali condition, other solvents and chemical reagents are not required to be added, a process route is shortened, the costs for production raw materials and running costs are saved, and solvent residues in the product and environmental pollution are relieved.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing VC by ultrasonically inducing crystallization of an aqueous solution of guaronic acid. Background technique [0002] Vitamin C (English: Vitamin C, also known as L-ascorbic acid) is an essential nutrient for higher primates and a few other organisms. In living organisms, vitamin C is an antioxidant because it protects the body from oxidizing agents. The general process of producing VC in enterprises is to use D-sorbitol as raw material, ferment and convert it into L-sorbose, and continue to ferment (with Na 2 CO 3 reaction) into gulon acid sodium salt; then gulon acid sodium salt is dissolved in inorganic acid, acid hydrolysis makes gulon acid, evaporates solvent to obtain guron acid crystal; gulon acid crystal powder undergoes methyl esterification reaction with methanol under the catalysis of sulfuric acid to obtain gulon Methyl guronate, me...

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Problems solved by technology

[0005] It can be seen from this that the traditional VC production process is as long as 9, not only that, but also has the following problems: (1) The process flow is long, the steps are cumbersome, and the production line investment cost and operating cost are high

(2) Large water consumption, large amount of sewage discharge, and high cost of wastewater treatment: Cologne esterification needs to react with flammable and explosive raw materials such as methanol or ethanol and other lower alcohols. Although the lower alcohols are dissociated after alkaline lactonization, It can be recovered and recycled by distillation, but a part of the recovery process will inevitably be lost, and a part of waste water will be generated at the same time

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