| 摘要 |
A process for purifying acrylamide or methacrylamide comprises heating the amide above its melting point, vaporizing the melted amide, and contacting amide vapours with a collecting liquid at a temperature below the melting point of the amide, the collecting liquid being non-reactive with the amide and having limiting solubility for it at the contact temperature used; the amide is condensed as a solid in the collecting liquid. The melted amide may be heated under reduced pressure, and the vapour contacted with the collecting liquid at below 50 DEG C. Suitable collecting liquids are hydrocarbons such as benzene, toluene, xylene, aromatic petroleum distillates, or alkanes (including gasoline and kerosene), chlorohydrocarbons such as ethylene dichloride, trichloroethylene and trichloroethane, esters such as ethyl, butyl and amyl acetate, butyl propionate and dimethyl phthalate, ketones such as methyl ethyl, methyl isobutyl and methyl hexyl ketone, and alcohols such as butyl, isobutyl and isodecyl alcohol. A polymerisation inhibitor may be added to the crude amide. |
