| 摘要 |
PURPOSE:To produce the titled substance in high yield and purity, without causing the contamination with impurities nor the polymerization of the sorbic acid, etc., by the purification of a crude sorbic acid, by dissolving the crude sorbic acid in petroleum, flashing the petroleum under reduced pressure, and passing through a separation column supplied with petroleum at the top in place of refluxing the distillation product. CONSTITUTION:A polyester prepared by the reaction of crotonaldehyde with a ketene is decomposed with hydrochloric acid. The crude sorbic acid separated from the reaction liquid is dissolved in petroleum at 100-140 deg.C, preferably 110-130 deg.C, and the solution is flashed with a thin-film evaporator under a reduced pressure of 20-60mmHg. The gas flow of evaporated sorbic acid and petroleum is introduced into a perforated plate separation column having a plate number of >=3, and at the same time, 0.2-1.0pt.wt. of petroleum is supplied to the vapor distilled out from the top of the separation column to effect the distillation and purification of sorbic acid. Various lubricating oils having a boiling point of 180-300 deg.C under normal pressure can be used as the petroleum used in the above process.
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