Study On Synthesis Technology Of Zinc Propionate As The Food Additive

Microwave chemistry is used as a green chemistry widely in organic chemicalsynthesis. Microwave heating can not only accelerate the rate of chemical reaction,and can improve the target product yield, at the same time it can save energy. Zincpropionate as food additive can not only prolong the time for eating the food, but alsothe zinc ions of zinc propionate as trace elements are needed by human bodymetabolism, the prop ionic acid in the decomposition of zinc propionate also are themiddle of the metabolism product of human and animal. Therefore, the synthesis ofanticorrosive and zinc supplementation of zinc propionate has very importantsignificance.In this paper, with the water as the solvent, zinc propionate was synthesized fromprop ionic acid and zinc oxide as the raw material under microwave irradiation andthe condition of conventional oil bath heating. The product was tested by IR spectra、TG、Elemental Analysis and EDTA coordination method. The main contents andconclusions are as follows:The synthesis for the technological conditions of zinc propionate was discussedunder the condition of conventional oil bath heating, all of the effects of the reactiontemperature, the feed ratio n(propionic acid): n(zinc oxide), the reaction time,deionized water on the yield of the zinc propionate were investigated. And on thebasis of single factor experiment, the three significant effects factors on the synthesisof zinc propionate were optimized by using the Design-Expert8.05software, and theexperimental results were discussed and summarized, the results showed that thereaction temperature was84℃, the feed ratio n(propionic acid): n(zinc oxide)was2.47:1, the reaction time was49.90min, the deionized water added about4.5timesas prop ionic acid volume. The average yield of zinc propionate was88.56%.Under the condition of microwave radiation, all of the effects of the reactiontemperature, the feed ratio n(propionic acid): n(zinc oxide), the reaction time,deionized water, adding amount of microwave irradiation power on the yield of thezinc propionate were investigated. The process condition was optimized by using theBox-Behnken center combination design principle and response surface methodologyon the basis of single factor experiment, and the optimization results were showed thatthe reaction temperature was80℃, the feed ratio n(propionic acid): n(zinc oxide) was2.23:1, the reaction time was12.31min, the deionized water added about4times as prop ionic acid volume, microwave irradiation power was300W, and the averageyield of the Product could reach93.70%.The results show that the synthesis of zinc propionate under microwave radiationwas superior to conventional heating, microwave radiation had to speed up thereaction rate, to shorten reaction time, to improve product yield and so on. The resultsshowed that zinc propionate were similar to calcium propionate, also zinc propionatehad efficient low toxicity and low price, it was a kind of high cost performance.