Cellulose ethers and method for producing the same

US6482940B1 · kind B1 · utility

Assignee

• Wolff Walsrode AG · DE

Inventors

• Erik-Andreas Klohr · Walsrode, DE
• Jörg Neubauer · Walsrode, DE
• Wolfgang Koch · Batavia, US
• Klaus Szablikowski · Walsrode, DE
• Detmar Redeker · Cologne, DE
• Wolfgang Wagenknecht · Teltow, DE
• Fritz Loth · Teltow, DE

Key dates

• Filing date: Dec 30, 1999
• Grant date: Nov 19, 2002
• Expiry date: Dec 30, 2019

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2531/985
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A cellulose ether that is predominantly substituted in the C3 position of the anhydroglucose unit of the cellulose is described. In an embodiment of the present invention, the partial degree of substitution in the C3 position of the cellulose ether is ≧60%, based on the total degree of substitution. Also described is a process for preparing the cellulose ether of the present invention. The process involves, reacting cellulose, dissolved in N-methylmorpholine-N-oxide monohydrate (NMMNO) and optionally other inert organic solvents, with alkylation reagents. The reaction takes place in the presence of: (i) an insoluble solid phase catalyst, e.g., solid ion exchange resins based on polystyrene having quaternary ammonium groups; (ii) stabilizers, e.g., propyl gallate; and (iii) optionally additional soluble co-catalysts, e.g., trimethylbenzylammonium hydroxide.