| 摘要 |
PURPOSE:To purify sorbic acid, with simple process, by dissolving crude sorbic acid continuously in petroleum at a specific temperature and at the same time, evaporating water and hydrochloric acid from the solution, separating the tar component, flashing sorbic acid and petroleum under reduced pressure using a thin-film evaporator, and recycling the residue. CONSTITUTION:A polyester obtained by the reaction of crotonaldehyde with a ketene is decomposed with hydrochloric acid, and the crude sorbic acid separated from the reaction liquid is purified by the following process. The crude sorbic acid is dissolved continuously in petroleum at 100-140 deg.C, preferably 110-130 deg.C, and at the same time, the remaining water and hydrogen chloride is evaporated from the petroleum solution. The solution is separated from tar component at the above temperature, and sorbic acid and petroleum are subjected to the flash evaporation by a thin-film evaporator in a vacuum of about 20-60mm.Hg. At the same time, the evaporation residue containing tar component and discharged from the bottom of the evaporator is recycled to the first process to obtain purified sorbic acid.
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