Process for the treatment of cellulose

US5473061A · kind A · utility

Assignee

• Rhone-Poulenc Rhodia Aktinegesellschaft · DE

Inventors

• Karl Bredereck · Stuttgart, DE
• Ties Karstens · Reutlingen, DE
• Harro Lentz · Siegen, DE
• Hans Steinmeier · Waldenbuch, DE

Key dates

• Filing date: Aug 30, 1994
• Grant date: Dec 5, 1995
• Expiry date: Aug 30, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08B1/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The process for the treatment of cellulose for activation for subsequent chemical reactions by bringing the cellulose in contact with liquid ammonia at a pressure higher than atmospheric pressure in a pressure vessel and subsequent expansion by rapid reduction of the pressure to atmospheric pressure, is carried out by using a cellulose pulp of an alpha-cellulose content of at least 92 mass %, letting the ammonia act on the pulp at room temperature or at a temperature higher than room temperature, after the expansion, removing the ammonia then still remaining in the pressure vessel except for a minimum content at which the state of activation reached by the action of the ammonia is still maintained and finally replacing the residual ammonia still needed to maintain the state of activation by another swelling or inclusion agent. The process is suitable, also on a large industrial scale, especially for the activation of pulp subsequently to be acetylated and makes possible to achieve a homogenous and high-grade activation. Further, no costly cooling apparatus is needed.