| 摘要 |
The invention relates to a continuous process for the purification of aqueous monochloroacetaldehyde solutions, which contain free hydrogen chloride and acetic acid from the preparation, by distillation under reduced pressure without introduction of a neutralisation step. The aqueous crude monochloroacetaldehyde solutions, which have been prepared by reaction of chlorine with vinyl acetate in water, are continuously fed into the upper half of a packed column with simultaneous continuous addition of water at the top of the column. With a product residence time in the column of at most 30 minutes, pure monochloroacetaldehyde in the form of a 45-89% strength by weight aqueous solution is continuously drawn off at the top of the column and the aqueous solution containing acetic acid and hydrogen chloride is continuously drawn off from the bottom of the column, under a pressure of 20-60 kPa.
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