Method for purifying acrylic acid or methacrylic acid by crystallization and distillation

US6541665B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Erik Bastiaensen · Kapellen, BE
• Bernd Eck · Viernheim, DE
• Joachim Thiel · Neustadt, DE

Key dates

• Filing date: Jan 2, 2001
• Grant date: Apr 1, 2003
• Expiry date: Jan 2, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/44
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In a process for the purification of acrylic acid or methacrylic acid by crystallization and distillation, the following steps are carried out:(a) crystallization of a mixture containing the acrylic acid or methacrylic acid with formation of product crystals having a higher concentration of acrylic acid or methacrylic acid and of a mother liquor,(b) distillation of at least part of the mother liquor from step (a) with formation of a distillation residue, which is at least partly removed, and of a top product,(c) crystallization of at least part of the top product from step (b) with formation of a crystallization residue, which is removed, and of crystals and(d) recycling of the crystals from step (c) to the crystallization (a).