Verfahren zum Isolieren, und zwar in konzentrierter Form aus einer wässrigen Lösung, von optischen Aufhellern

摘要

1304349 Triazinylamino stilbene sulphonic acid salts IMPERIAL CHEMICAL INDUSTRIES Ltd 31 March 1970 [9 April 1969] 18216/69 Heading C2C [Also in Division D1] Optical brighteners of the formula where M is an alkali metal, ammonium or substituted ammonium group, X is an alkoxy group, R1 is an optionally substituted alkyl group and R2 is hydrogen or an optionally substituted alkyl, cycloalkyl or aryl group, are isolated in concentrated form from aqueous solutions by adding to the aqueous solution at 60-100‹ C. an alkali metal, ammonium or substituted ammonium salt of a halogen acid or sulphuric acid in an amount sufficient to precipitate an oil containing the optical brightener and separating the oil from the aqueous solution, the aqueous solution of optical brightener having heen obtained by condensing cyanuric chloride in any order with an alcohol XOH, an amine NHR1R2 and 4,41- diaminostilbene- 2, 21-di.sulphonic acid. The salt, which is preferably NaCl, may be added in amounts of up to 5% by wt. of the aqueous solution. The oil generally comprises 40-60% optical brightener, up to 5% salt and the remainder water. It may be dried to obtain a powder or dissolved in the required solvent for application to substrates. Examples describe the preparation and isolation of Na and K salts of compounds derived from 2-methoxy-4- N-methylanilino-, 2-ethoxy-4-N-methylanilino-, 2 - methoxy - 4 N - #- cyanoethylanimo -, 2- methoxy - 4 - N - #- hydroxyethylamino-, 2 - methoxy - 4 - ethylamino-, 2 - methoxy- 4 - diethylamino-, 2 - methoxy - 4 - N - methylmetanilino- and 2 - methoxy - 4 - N - methylsulphanilino-triazines.