Patent GB-1073256-A (GB)
Title: New bis-oxazoles,process for their preparation and their use
IPC: C01B31/30
Filed: 1964-08-21
Abstract: Bis-oxazoles of the general formula <FORM:1073256/C4-C5/1> in which R represents a p-phenylene nucleus which may carry substituents and A1 and A2 are the same or different and each represents a benzene residue which may carry substituents may be used as brightening agents in combination with detergents. They may be added to (a) salts of sulphonate detergents, such as sulphonated benzimidazoles carrying higher alkyl radicals in the 2-position; salts of monocarboxylic acid esters of 4-sulphophthalic acid with higher fatty alcohols; salts of fatty alcohol sulphonates, alkylarylsulphonic acids, condensation products of higher fatty acids with aliphatic hydroxy sulphonic or aminosulphonic acids, cellulose sulphite waste liquor, or condensation products of formaldehyde with (possibly alkylated) naphthalene sulphonic acids; (b) nonionic detergents, for example polyglycol ethers derived from ethylene oxide and higher fatty alcohols, alkyl phenols or fatty amines; and (c) soaps.ALSO:The invention comprises bis-oxazoles of the formula <FORM:1073256/C2/1> in which R represents a p-phenylene radical which may be substituted and A1 and A2 are the same or different and each represents a benzene residue which may be substituted. Substituents on the benzene rings A1 and A2 may be, for example, halogen atoms; phenyl groups; saturated C1-C12 non-aromatic hydrocarbon groups; aralkyl radicals, cyanoalkyl radicals, carboxyalkyl groups or carbalkoxyalkyl groups containing up to 12 carbon atoms; or carboxyl, carboxylic acid ester, carboxylic amide or carboxylic hydrazide groups; or vicinal carbon atoms of the benzene residues A1 and A2 may complete a 6-membered alicycle. The phenylene nucleus may carry, for example, a halogen atom or a C1-C4 alkyl group. The bis-oxazoles may be prepared by the following methods:  (a) by condensing OHC-R-COOH with a compound of formula <FORM:1073256/C2/2> to form a carboxylic acid of formula <FORM:1073256/C2/3> which is reacted with an o-hydroxyamino compound of formula <FORM:1073256/C2/4> at an elevated temperature preferably in the presence of a condensation catalyst, e.g. boric acid; (b) by reacting at least one orthohydroxyamino compound of formula <FORM:1073256/C2/5> or <FORM:1073256/C2/6> with a p-carboxy cinnamic acid of the formula HOOC-HC = CH-R-COOH.ALSO:Bis-oxazoles of the general formula <FORM:1073256/C3/1> in which R represents a p-phenylene nucleus which may carry substituents and A1 and A2 are the same or different and each represents a benzene residue which may carry substituents, are used as optical brightening agents for (a) lacquers, e.g. acrylic resin lacquers, alkyd resin lacquers and cellulose lacquers such as acetylcellulose and nitrocellulose lacquers; and (b) films, foils, ribbons or other shaped articles of polyamides, polyesters or polyolefines or other resins, e.g. polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol and polyvinyl esters of organic acids, e.g. polyvinyl acetate.  The brightening agents may be added to the resins before or during shaping.  Examples are given of the treatment of (a) a polyester granulate from polyterephthalic acid ethylene glycol ester (Example 8); (b) a polyamide in chip form prepared from hexamethylene diamine adipate (Example 9); (c) polyethylene foil (Examples 12 to 14); and (d) a polyvinyl chloride foil (Example 16).ALSO:Bis-oxazoles of the general formula <FORM:1073256/D1-D2/1> in which R represents a p-phenylene radical which may be substituted, and A1 and A2 are the same or different and each represents a benzene nucleus which may be substituted, are used as optical brightening agents for brightening synthetic fibres e.g. of cellulose esters such as cellulose propionate or acetyl cellulose, of polyamides, and of polyesters or polyolefins, and also for brightening natural fibres, for example, wool and cotton.  Examples are given of the use of the bis-oxazoles in the brightening of (a) a polyamide or polyester fabric (Ex. 7), (b) polypropylene fibres (Ex. 10), (c) polyethylene fibres (Ex. 11) and (d) polyvinylidene chloride fibres.