GB507126A - Improvements in the manufacture of organic esters of cellulose - Google Patents

Abstract

507,126. Cellulose esters. BRITISH CELANESE, Ltd. Aug. 9, 1938, No. 23458. Convention date, Aug. 14, 1937. [Class 2 (ii)] Cellulose-acetates and other organic esters of cellulose are stabilized by subjecting them, after ripening, to a treatment with a tertiary amine in which at least two aryl or aralkyl radicles are attached to a tertiary nitrogen atom. Examples of such amines are diphenyl aniline, dibenzyl aniline, benzyl methyl aniiine, benzyl ethyl aniline and benzyl phenyl aniline. The amine may be added to the solution of the ripened esters before precipitation, or it may be incorporated with the ester during precipitation, or after precipitation preferably with the ester in finely divided form and in suspension. During the ripening process, small quantities of inorganic salts such as aluminium chloride and zinc chloride, or hydrochloric acid may be added since these assist in reducing the formation of unstable compounds ; and the catalyst used for esterification may be whoily or partly neutralized prior to the addition of the amine. Cellulose esters which are to be treated after precipitation, may during precipitation be treated with hypochlorite &c. to improve their colour. The Specification as open to inspection under Sect. 91 refers also to the treatment of nitrocellulose and of cellulose ethers. This subjectmatter does not appear in the Specification as accepted.