| 摘要 |
1,235,634. Acrylic acid. KNAPSACK A.G. 29 Oct., 1969 [29 Oct., 1968], No. 52973/69. Heading C2C. Pure acrylic acid is obtained from aqueous crude by extracting with 3,3,5-trimethylcyclohexanone and/or isophorone, water-washing the organic extract, dehydrating the extract in a first distilling zone, and distilling the base product therefrom in a second distilling zone to obtain the pure acrylic acid. The extracting and water washing may be simultaneous and by countercurrent. The aqueous phase from the extraction may be further distilled, the solvent separated as an azeotrope and recycled. Examples describe the use of a pulsation column in the extraction. Stabilizers, e.g. methylene blue, may be present.
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