Process for combining glycerol triacetate through acid ion liquid catalyst

Abstract

The invention relates to a process for combining glycerol triacetate through an acid ion liquid catalyst. The process includes utilizing glycerol, acetic acid, a solvent and the catalyst as raw materials to conduct esterification reaction, then adding acetic anhydride to conduct acylation reaction, separating the solvent with excess acetic acid after the acylation reaction is finished, utilizing the mixture of the solvent and the acetic acid to serve as a raw material of the next batch, separating the mixture of the ion liquid catalyst and a glycerol triacetate product in remainders in a reaction kettle, using the ion liquid catalyst in circulation mode and removing micro acetic acid in glycerol triacetate to produce food-grade glycerol triacetate. Detailed process is shown in an instruction book. The process has the advantages that the ion liquid catalyst does not corrode equipment, and side reactions such as oxidation, carbonization and polymerization caused by a liquid strong acid catalyst are basically removed. The catalyst is repeatedly used, pollution of waste water to environment is removed, and production cost is reduced. Discharge of waste sludge and alkali liquor is removed. The process is short in flow and free of pollutant discharge and achieves clean production process. The yield of the glycerol triacetate is 99%, and acidity of the glycerol triacetate is lower than 0.002%.

Description

technical field [0001] The invention relates to fine chemical product technology, in particular to a process for synthesizing glycerol triacetate with an acidic ionic liquid catalyst. Background technique [0002] Glyceryl triacetate, also known as glycerol triacetate, is a colorless, odorless, oily liquid, non-toxic and non-irritating. Its English name is Glycerol Triacetate, its molecular formula is C9H14O6, and its molecular weight is 218.21. [0003] Glyceryl triacetate is miscible with organic solvents such as alcohol, ether, benzene, and chloroform, and can dissolve high molecular compounds such as nitrocellulose, acrylic resin, and polyvinyl acetate. Because triacetin has good gelling effect and physiological inertness, it is widely used as a plasticizing and curing agent for cellulose acetate in cigarette filters, a food additive, a cosmetic fixative, and a lubricating matrix. Glyceryl triacetate is widely used in tobacco, food and metallurgical industries as a saf...

AI Technical Summary

Problems solved by technology

[0005] Although sulfuric acid or p-toluenesulfonic acid can make the reaction obtain a relatively ideal esterification rate, and the price is low, but due to the strong acidity and oxidative properties of sulfuric acid in the reaction process, side reactions such as oxidation, carbonization, polymerization, rearrangement, etc. Occurrence, poor selectivity, darker product color; at the same time, concentrated sulfuric acid will also cause corrosion to equipment, and it is difficult to recycle, resulting in high production costs, high pressure on environmental protection, etc.

[0006] For this reason, scientific and technological workers at home and abroad have carried out a lot of work to improve the process, as U.S. Patent USP3108133 discloses a kind of process of purifying glycerol triacetate under high temperature and low pressure conditions; Method for purifying glyceryl triacetate with methanol or ethanol and deacidifying glyceryl triacetate with carbon dioxide or nitrogen stripping; Chinese patents such as CN1022010330A, CN101973877A and other patents disclose the use of activated carbon adsorption and decolorization methods to refine glyceryl triacetate, from According to the patent report, the purpose is to reduce the acidity of the product triacetin, but the synthesis process of triacetin is not substantially changed, and processes such as washing with water and alkali neutralization are still required, resulting in a large amount of waste water and waste residue emissions

In the Chinese patent CN102020558A, a method for synthesizing triacetin with solid superacid as a catalyst is disclosed, which can reduce pollutant emissions in the synthesis of triacetin from the patent literature, but in the synthesis of triacetin from glycerol and acetic acid In the reaction system, there is still the influence of by-product water on the stability of the catalyst and the influence of the mechanical strength of the catalyst under strong stirring. Only the results of 10 cycles are given in the patent literature, and there are no reports of related industrial applications.

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