| 摘要 |
1458397 Acrylic acid DEUTSCHE GOLDUND SILBER-SCHEIDEANSTALT 10 Dec 1973 [27 Dec 1972] 07195/76 Divided out of 1458396 Heading C2C Pure acrylic acid is prepared from a solution of acrylic acid in a mixture of water and organic liquid which is a monohydric aliphatic alcohol (4 to 10 C), an acetate or acrylate thereof or a mixture of these alcohols and/or esters by a two-stage distillation at reduced pressure, the substances with lower boiling points than acrylic acid being removed in the first stage and acrylic acid and the organic liquid being separated in the second stage. The organic liquid has a higher boiling point than acrylic acid, forms an azeotrope with water but not with acrolein or acrolein/water mixture, and produces with acrylic acid a solution in which the acrylic acid has an activity coefficient smaller than 1À5. The acrylic acid solution may be from the catalytic oxidation of propylene or acrolein and impurities comprise acetic acid, formaldehyde, acrolein and furfurol. An example describes the use of 2-ethylhexanol as the organic liquid. |
