Patent GB-181395-A (GB)
Title: Manufacture of cellulose ethers
IPC: C08B11/02
Filed: 1922-06-12
Abstract: Alkyl ethers of cellulose or of its conversion products which ethers are insoluble in water at 16 DEG  C. and above but which are soluble or swell in water at lower temperatures, are prepared by treating an alkyl ether soluble in water at 16 DEG  C. with caustic alkali and an alkylating-agent, the content of caustic alkali in the reaction mixture amounting to not less than one-tenth and not more than one fourth of the quantity of water present; for example, the reaction mixture may contain for every one part of ethyl celulose soluble in water, 0.3-1 part of caustic alkali and 2-5 parts of water, or 0.75-2.5 parts of caustic alkali and 5-10 parts of water, or 2-5 parts of caustic alkali and 10-20 parts of water.  In carrying out the process, an ethyl ether of cellulose, soluble in water at 16 DEG C., is first made for example by ethylation in known manner of an alkali cellulose or a conversion product or derivative of cellulose soluble in alkali, and the ether isolated and subjected to a further ethylation under the conditions defined above; or the reaction continued in the crude reaction mixture with or without the elimination of a part of the water and after the addition of the necessary quantity of caustic alkali; for such further ethylation a temperature of 40-60 DEG  C. should be maintained if diethyl sulphate is employed, and 70-150 DEG  C. if ethyl halide is used; the caustic alkali and ethylating-agent may be added all at once or in several portions. The ether is filtered off from the reaction mixture which may be diluted with water and may be neutralized or acidified; the ether after washing with water at 16 DEG  C. or above, may be immediately dried, or it may be treated with dilute acid, again washed, and then dried.  Mixed ethers may be obtained by first preparing a water-soluble ether by the use of one alkylating-agent, for instance, a methyl ester, and then further treating this ether with another alkylating-agent, for instance, an ethyl ester.  The Specification includes a number of examples for the manufacture of ethyl ethers, in which the starting materials are an aqueous alkaline solution of a cellulose derivative or conversion product soluble in alkali, and the caustic soda and ethylating-agent are introduced as successive additions, and the products differ slightly in their behaviour to cold water; a range of organic solvents for the finished ethers is specified. Specifications 6035/13, 14339/14 and 149,320 are referred to.  The Specification as open to inspection under Sect. 91 (3) (a) refers to the capacity of the ethers to absorb water at temperatures below 16 DEG  C. so that articles made from these ethers may be readily impregnated or incorporated with substances soluble in water, for example, dyes; and to the use of these ethers in the manufacture of artificial silk, hair, &c., photographic emulsions, lacqueurs, &c., sizes, coatings, dressings, fillings and finishings for textiles, paper, leather, &c., printing-agents and compositions, agents for fixing pigments, adhesives, cements, varnishes, paints, films, artificial leather, and book cloth; and for such uses they may be combined with other water-soluble or water-insoluble cellulose derivatives and other colloids, and with binding-and thickening-agents, and softening- and plastifying-materials; and it includes an example in which the starting material is a sulphite-cellulose impregnated with caustic alkali solution.  This subject-matter does not appear in the Specification as accepted.ALSO:The Specification as it became open to inspection under Sect 91 (3) (a) includes the preparation of adhesives cements, sizes, dressings, &c., employing alkyl ethers of cellulose or of its conversion products which ethers are insoluble in water at 16 DEG  C. and above but which are soluble or swell in water at lower temperatures.  They are prepared by treating an alkyl ether soluble in water at 16 DEG  C. with caustic alkali and an alkylating agent, the content of caustic alkali in the reaction mixture amounting to not less than one-tenth and not more than one-fourth of the quantity of water present.  For such uses the ethers may be combined with other water-insoluble cellulose derivatives and other colloids, and with binding- and thickening-agents, and softening- and plastifying-materials.  This subject-matter does not appear in the Specification as accepted.ALSO:The Specification as it became open to inspection under Sect 91 (3) (a) includes the statement that alkyl ethers of cellulose or of its conversion products which ethers are insoluble in water at 16 DEG  C. and above but which are soluble or swell in water at lower temperatures, prepared by treating an alkyl ether soluble in water at 16 DEG  C. with caustic alkali and an alkylating agent, the content of caustic alkali in the reaction mixture amounting to not less than one-tenth and not more than one-fourth of the quantity of water present, may readily be impregnated or incorporated with dyes and further includes the preparation of printing-agents and thickening-agents for printing-compositions employing these ethers.  For such uses they may be combined with other water-soluble or water-insoluble cellulose derivatives and other colloids, and with binding- and thickening-agents, and softening- and plastifying-materials.  This subject-matter does not appear in the Specification as accepted.