Hoechst Aktiengesellschaft

Rhone-poulenc Rhodia Aktiengesellschaft

Karl Bredereck

Christian Schumacher

Andreas Von Der Eltz

Ties Karstens

Hans Steinmeier

Brigitte Horsch

Harro Lentz

Emy Togelang

Markus Strauss

Use of carbohydrate compounds as auxiliaries for dyeing and printing fiber materials Use of carbohydrate compounds of the formula (1)

Use of carbohydrate compounds as auxiliaries for dyeing and printing

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.

Process for the treatment of cellulose

A process is disclosed for the preparation of water-soluble cellulose ethers, comprising the steps of activating cellulose with ammonia, alkalizing the activated cellulose, and etherifying the alkali cellulose. In the process, the activated cellulose is alkalized in the presence of ammonia and, optionally, in the presence of an organic solvent, and the ammonia is removed from the alkali cellulose in the presence of the alkalizing agent and, optionally, the organic solvent. Etherification proceeds in a medium which contains at least portions of said organic solvent. The organic solvent comprises, in particular, an alkanol which has from 1 to 6 carbon atoms. For the etherification step, carboxymethylation or hydroxyethylation is preferred.

Process for the preparation of cellulose ethers from ammonia-activated

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Stuttgart, Germany

Karl Bredereck