Abstract: A process for the preparation of a cellulose ether by reacting in a heterogenous reaction mixture an alkaline solution and an etherifying agent with a fibrous cellulose. The total of the required stoichiometric amount of the alkaline solution and at least a portion of the etherifying agent required in producing the cellulose ether are admixed (e.g. in a mixing nozzle) at sufficiently low temperature to suppress reaction between the alkaline solution and the etherifying agent. The admixture is then contacted with the cellulose fibers, preferably by spraying the admixture thereupon. Additional of the etherifying agent if required is then added to the reaction mixture, and the heterogenous reaction mixture is agitated and reacted at an initial temperature below 40.degree. C. sufficient to produce alkalization of the cellulose. Thereafter the temperature is increased above 40.degree. C., preferably incrementally or gradually up to about 100.degree. C., preferably to 80.degree. C.

Abstract: Improved reaction efficiencies are obtained when water is removed during a reaction of alkali cellulose and an etherifying agent to produce cellulose ethers. The removal of water during the etherification reaction reduces the amount of by-products formed during the reaction.

Abstract: 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.

Abstract: A process for the purification of cold-water soluble cellulose ethers containing alkali metal halides consisting essentially of suspending a cold-water-soluble cellulose ether crude reaction product containing 25% by weight or more of alkali metal halides, based on the dry weight, in an aqueous solution containing from 4% to about 25% by weight of one or more water-soluble salts of acids selected from the group consisting of polybasic inorganic acids and organic polycarboxylic acids with agitation at a temperature of from 10.degree. C. to 50.degree. C., separating the purified cellulose ether solids and optionally repeating the suspending and separating steps one or more times. The resulting material can be employed in washing and cleansing composition slurries for spray-drying. The process is especially suitable for the treatment of methyl cellulose or water-soluble mixed ethers of methyl or ethyl cellulose with a sodium sulfate solution.

Abstract: In the preparation of organosoluble cellulose ethers, the content of alkali metal (hydroxides and the salts thereof) in the resulting cellulose ether is reduced by forming a solution of the cellulose ether and an organic solvent, converting the alkali metal hydroxide therein to an alkali metal salt and heating the resulting solution at conditions sufficient to (1) increase the size of the alkali metal salt particles and (2) remove any water therefrom. Filtering the resulting mixture and drying the filtrate yields a cellulose ether containing a very small percentage of alkali metal salt, e.g., often less than about 500 ppm.

Abstract: The present invention is related to a new process for producing cellulose C.sub.1 -C.sub.4 -alkyl ethers by subjecting cellulose to reaction with an alkali metal hydroxide and subjecting the resulting alkali metal salt of cellulose to reaction with an alkyl halide wherein the alkyl group contains 1 to 4 carbon atoms. The new process is characterized by subjecting 1 part by weight of cellulose to reaction with 0.5 to 4 parts by weight of the alkyl halide in a positive mixer having a fast-running mixing appliance and a container with adjustable internal pressure and cooling of the internal container wall, adding the alkali metal hydroxide in a concentrated aqueous solution or in a substantially water-free and finely divided state, and adjusting the pressure in the reaction vessel with cooling in such a way that the temperature of the reaction mixture remains in the range of from 15.degree. to 40.degree. C., and raising the temperature of the reaction mixture after termination of the alkalization to from 50.

Abstract: This invention comprises a gas-permeable contact lens consisting essentially of a plasticized cellulose resin selected from a partially esterified or partially etherified cellulose polymer plasticized with a compatible plasticizer in an amount sufficient to increase the gas permeability of the cellulose resin.

Abstract: In the process for the preparation of low-substituted cellulose ethers comprising the successive steps of etherification of alkali cellulose, neutralization of the crude cellulose ether, washing, drying and pulverization, the neutralization step is carried out in two stages, i.e., by first employing 5 to 80% of an acid stoichiometrically required and then adding an additional amount of the acid to complete neutralization. The cellulose ethers thus prepared can readily be pulverized into fine powder having a very good flowing property and yet an excellent binding force, and work as a suitable disintegrator in tablets.

Abstract: Novel absorber for the blood and the like, particularly a tampon for menses, which is made of the filaments of a lower alkyl or a lower hydroxyalkyl substituted cellulose ether. The absorber is insoluble in the blood and the like when it is used, but it is dispersible and soluble in water when it is thrown away.

Abstract: This invention comprises a gas-permeable contact lens consisting essentially of a plasticized cellulose resin selected from a partially esterified or partially etherified cellulose polymer plasticized with a compatible plasticizer in an amount sufficient to increase the gas permeability of the cellulose resin.