Optische Aufhellmittel

摘要

The invention comprises compounds of the formula or n which X is hydrogen or methyl and m is 1 or 2. They may be prepared by reacting the corresponding chloromethyl compounds with a pyridine compound of formula in which X is hydrogen or methyl. The chlormethyl compounds used as starting materials may be prepared by introducing 1 or 2 chloromethyl groups into 2,5-di-[benzoxcyolyl-(21)]-furan compounds of formula in which Z stands for H or CH3, by reaction with hydrogen chloride and formaldehyde or with dichloromethyl ether in the presence of chlorosulphonic acid. The 2,5-di-[benzoxazoly-1-(21)]-furan compounds may themselves be formed by reacting furan-2,5-dicarboxylic acid or a functional derivative thereof at 160-260 DEG C., preferably in the presence of a condensation catalyst, with 1-amino-2-hydroxy-5-methyl-benzene in the molecular ratio of 1 : 2.ALSO:New compounds having the formula or in which X is hydrogen or methyl and m is 1 or 2 are used for the optical brightening of fibrous materials made of cotton, viscoses, acetate rayon, polyvinyl chloride, polyethylene, polypropylene and polyamides, and polyacrylonitrile and acrylonitrile copolymers. The fibrous materials may be treated with aqueous solutions of the optical brightening agents, preferably at 50-100 DEG C. The solutions used may be partial, weakly alkaline or acidic. The new compounds may be added to bleaching baths, for example, chlorite bleaching baths and may also be used in conjunction with a dispersant, a water-soluble inorganic salt or a dressing agent. In an example a polyacrylonitrile fabric is treated at 60-100 DEG C. with a bath containing one of the new optical brightening agents, formic acid, an adduct from ethylene oxide and octadecyl alcohol and sodium chlorite.