Superabsorbent polymer made from acrylic acid

US7964689B2 · kind B2 · utility

Assignee

• Evonik Stockhausen GmbH · US

Inventors

• Stefan Nordhoff · Recklinghausen, DE
• Axel Kobus · Langen, DE
• Stefan Gross · Lörrach, DE
• Hans-Rolf Lausch · Alzenau, DE
• Torsten Balduf · Pfungstadt, DE
• Roland Fornika · Dülmen, DE
• Guenther Bub · Marl, DE

Key dates

• Filing date: Sep 13, 2010
• Grant date: Jun 21, 2011
• Expiry date: Sep 13, 2030

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/43
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a superabsorbent polymer that includes a (meth)acrylic acid made by a process that comprises the following process steps: a) (meth)acrylic acid is crystallized out from a mother liquor; b) crystallized (meth)acrylic acid is separated from the mother liquor; c) at least part of the separated (meth)acrylic acid crystals are melted; d) the melted part is at least partially recycled to the step a) or step b). The superabsorbent polymer according to the present invention includes an process to make (meth)acrylic acid, the apparatus suitable for implementing the process, and the use of the apparatus for the production of (meth)acrylic acid characterized by a high purity of the thereby obtainable (meth)acrylic acid as well as by a high efficiency with regard to the achievable yield and necessary energy requirement, thereby providing an improved superabsorbent polymer.