Method for producing cellulose derivatives

US6146858A · kind A · utility

Assignee

• Wolff Walsrode AG · DE

Inventors

• Rainhardt Koch · Neunburg vorm Wald, DE
• Frank Berendes · Hachenburg, DE
• John J. Foster · Windom, US
• Hans-Georg Rast · Odenthal, DE
• Jurgen Engelhardt · Bad Fallingbostel, DE
• Jörg Neubauer · Walsrode, DE
• Wolfgang Koch · Batavia, US
• Klaus Szablikowski · Walsrode, DE

Key dates

• Filing date: Feb 14, 2000
• Grant date: Nov 14, 2000
• Expiry date: Feb 14, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08B11/08
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Samples of commercial cellulose having high crystallinity (>80%) and a degree of polymerization of approximately 1500 were pretreated enzymatically under various conditions with commercial endoglucanases, before the chemical conversion to substituted cellulose derivatives was carried out. The enzymatically pretreated cellulose samples exhibited a significantly higher substitution, up to 222% higher, in comparison with control samples which had been treated with buffer without enzyme. The increase in substitution during the chemical reaction could be observed in the presence of various amounts of alkali, but fell as the amounts of alkali decreased. At the same degree of substitution of the cellulose derivative, the use of cellulose pretreated with endoglucanase significantly reduced the amount of alkali required by 60%, as compared with the use of cellulose pretreated only with buffer. Furthermore, by reducing the amount of water used in the reaction mixture in the chemical reaction, it was possible further to increase the substitution of enzymatically pretreated cellulose.