Process for preparing cellulose ethers with recovery of alkali

US5840882A · kind A · utility

Assignee

• Clariant Corporation · DE

Inventors

• Reinhard Doenges · Bad Soden, DE
• Rudolf Ehrler · Frankenthal (Pfalz), DE

Key dates

• Filing date: Aug 20, 1997
• Grant date: Nov 24, 1998
• Expiry date: Aug 20, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08B11/20
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Cellulose ethers which contain hydroxyalkyl groups are prepared, with the recovery of sodium hydroxide, by cellulose being etherified with alkylene oxide in a water-containing organic suspension medium in the presence of at least 1.0 mol of sodium hydroxide per mole of anhydroglucose units, the water-containing organic suspension medium being separated off after the etherification reaction is complete, the crude cellulose ether being extracted with a suitable solvent mixture, the lower-boiling organic components being distilled off from the solvent mixture after the extraction, the water-containing organic suspension medium separated off being added to the distillation residue of the solvent mixture to form a multiphase mixture, the bottom phase of the multiphase mixture being separated and the sodium hydroxide present in the bottom phase being reused.