Method for purifying sodium dehydroacetate

Abstract

The invention discloses a process for purifying sodium dehydroacetate by using supercritical fluid crystallization. The process comprises the following steps: (1) spraying neutralized impurity-containing 90 DEG C sodium dehydroacetate solution from the top of an extraction tower by using a feedstock pump, feeding supercritical fluid to the bottom portion of the extraction tower, and controlling the temperature of the supercritical fluid to be 33 to 36 DEG C, the pressure to be 9 to 11MPa and the flow to be 15 to 30m<3> / min; (2) reducing the pressure of high-pressure supercritical fluid containing dissolved sodium dehydroacetate to be below the critical pressure of the supercritical fluid through a throttling valve, and then enabling the supercritical fluid to enter a separation kettle; (3) after extraction of sodium dehydroacetate, enabling the product to sequentially pass through dehydration and drying processes. The process for purifying sodium dehydroacetate has the advantages that the process is simple and the equipment structure is compact; since the crystal layer is formed on the heat transfer surface but is not suspended in liquid during the process, the blockage of the equipment and pipes is avoided, the production faults are reduced, the purity of the product produced by using the process is high, the bioactivity is good and the grain size is uniform.

Description

technical field [0001] The invention relates to a method for purifying sodium dehydroacetate, in particular to a method for purifying sodium dehydroacetate with a supercritical fluid. Background technique [0002] Sodium dehydroacetate is a food preservative and preservative. This product has a strong antibacterial effect on yeast, spoilage bacteria and mold in food, and is widely used in antisepsis and preservation of meat, fish, vegetables, fruits, beverages, pastries, etc. Spectrum antibacterial agents. At present, the equipment for large-scale production of sodium dehydroacetate at home and abroad is a general enamel reaction kettle, and the mature process is roughly as follows: that is, neutralization reaction occurs between dehydroacetic acid and sodium hydroxide, and then cooled and crystallized by an enamel kettle, dehydration, Finished products are obtained through drying, packaging and other processes. However, due to the poor control of the cooling temperature o...

AI Technical Summary

Problems solved by technology

At present, the equipment for large-scale production of sodium dehydroacetate at home and abroad is a general enamel reaction kettle, and the mature process is roughly as follows: that is, neutralization reaction occurs between dehydroacetic acid and sodium hydroxide, and then cooled and crystallized by an enamel kettle, dehydration, Finished products are obtained through drying, packaging and other processes. However, due to the poor control of the cooling temperature of the enamel kettle, the material is easy to stick, the yield is not high, the purity is greatly affected, and the appearance is very bad.

Chinese patent CN102219770 discloses a method for purification by membrane filtration, but with this method, the product purity still does not meet the requirements

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