Patent GB-834903-A (GB)
Title: Method of optically brightening materials
Filed: 1956-09-25
Abstract: Compounds of the formula <FORM:0834903/IV (b)/1> <FORM:0834903/IV (b)/2> wherein R1 stands for hydrogen or an alkyl group, R2 stands for hydrogen, or an alkyl, aryl, acyl, cyano, or carboxyl group which may be esterified or a carbonamide group which may be substituted by alkyl, aryl or aralkyl radicals, and in which the aromatic rings, including any which may be present in R2 may be substituted with halogen atoms or hydroxyl, alkoxy, alkyl, aryl, aralkyl, sulphonic acid, sulphonamide, nitro, cyano, or carboxyl (which may be esterified) groups or a carbonamide group which may be substituted by alkyl, aryl, aralkyl radicals or an amino group which may also be substituted by alkyl, aryl or aralkyl radicals, possibly sulphonated, are prepared by reacting a hydroxy - naphthaldehyde such as 2 - hydroxy - 1 - naphthaldehyde, 1 - hydroxy - 2-naphthaldehyde, 1 - hydroxy - 4 - methoxy - 2-naphthaldehyde, 1 - hydroxy - 4 - chloro - 2-naphthaldehyde or 1 - hydroxy - 4 - bromo - 2-naphthaldehyde with a carboxylic acid or an ester which contains a methylene group adjacent the carboxyl group such as malonic acid, cyanacetic acid, acetoacetic acid, malonic acid diethylester and cyanoacetic acid ethylester.  The reactions are effected in the presence of piperidine, added dropwise. In Example (8) 5,6 benzocoumarin-3 carboxylic acid ethyl ester obtained as above is boiled with sodium hydroxide and treated with hydrochloric acid to give 5, 6-benzocoumarin-3 carboxylic acid.  In Example (9) 2-hydroxy-1 naphthaldehyde is heated with sodium acetate and acetic acid anhydride to give 5,6-benzocoumarin.ALSO:Textiles, paper, straw and leather are treated with a substantially colourless fluorescent benzocoumarin compound, which may have the formula <FORM:0834903/IV(c)/1> or <FORM:0834903/IV(c)/2> wherein R1 is hydrogen or an alkyl group and R2 is hydrogen or an alkyl, aryl, acyl, cyano, or carboxyl group, which may be esterified, or a carbonamide group, which may be substituted by alkyl, aryl or aralkyl radicals.  The aromatic rings, including any which may be present in R2, may be substituted with halogen atoms or hydroxyl, alkoxy, alkyl, aryl, aralkyl, sulphonic acid, sulphonamide, nitro, cyano, or carboxyl groups, which may be esterified, or carbonamide groups, which may be substituted by alkyl, aryl or aralkyl radicals, or amino groups, which may also be substituted by alkyl, aryl or aralkyl p radicals, possibly sulphonated.  The compounds may be applied in aqueous solution to natural fibres, and water-insoluble compounds may be applied to artificial fibres in aqueous dispersion or organic solution.  The compounds may also be applied in conjunction with detergents.  The examples refer to the treatment of cellulose acetate, polyacrylonitrile, polyglycol terephthalate and polyamide fibres, the compounds specified being 5,6-benzocoumarin, 5,6 - benzocoumarin - 3 - carboxylic acid ethyl ester, 5,6-benzocoumarin-3-carboxylic acid nitrile, 3-acetyl-5,6-benzocoumarin and 5,6-benzocoumarin-3-carboxylic acid monmethyl amide.  The treating baths are compounded by adding the benzocoumarin compound in alcoholic or dioxane solution to an aqueous bath which contains either oleyl alcohol sulphonate or paraffin sulphonate and, in certain examples, also formic acid, ortho-phenyl-phenol or benzoic acid, or, as in Example 8, to an aqueous bath containing sulphuric acid.  In Example 3 a trace of ammonia is added to the bath.  In Example 4, the benzocoumarin compound is compounded with a formaldehyde-hydroxynaphthalene sulphonic acid condensation product and dispersed in water.  The treating baths may be at 30-70 DEG  C., or the bath containing the fibres may be heated to and maintained at the boil.ALSO:Substantially colourless fluorescent benzocoumarin compounds which may have the formula <FORM:0834903/IV (a)/1> or <FORM:0834903/IV (a)/2> wherein R1 is hydrogen or an alkyl group and R2 is hydrogen or an alkyl, aryl, acyl, cyano, or carboxyl group, which may be esterified, or a carbonamide group, which may be substituted by alkyl, aryl or aralkyl radicals, are incorporated in solutions from which artificial fibres or films are made.  The aromatic rings, including any which may be present in R2, may be substituted with halogen atoms or hydroxyl, alkoxy, alkyl, aryl, aralkyl, sulphonic acid, sulphonamide, nitro, cyano, or carboxyl groups, which may be esterified, or carbonamide groups, which may be substituted by alkyl, aryl or aralkyl radicals, or amino groups, which may also be substituted by alkyl, aryl or aralkyl radicals, possibly sulphonated.  The compounds may be included in spinning compositions for polyester, polyamide, polyurethane or polyacrylonitrile fibres.  In Example 10, an alcoholic solution of 5,6-benzocoumarin-3-carboxylic acid ethyl ester is added to a spinning solution of cellulose acetate in acetone.