GB796524A - Improvements in or relating to optical whitening agents - Google Patents

Abstract

New whitening agents have the general formula <FORM:0796524/IV (b)/1> where R1 is an amino group, or a residue of a primary or secondary amine which does not contain an auxochrome or a chromophore, and which is linked to the triazine ring through its nitrogen atom, and R2 is chlorine, hydroxyl or has the same meaning as R1. The compounds and their water-soluble salts, such as alkali-metal salts exhibit a green fluorescence, and have a good affinity for cellulosic materials, particularly cotton and linen textiles and paper. They are prepared by reacting a compound of the above formula in which all the substituents are chlorine with a compound HR1 at neutral pH and 25-50 DEG C., leaving R2 as Cl, which may be replaced by -OH by treatment with sodium hydroxide solution, or by -R2 by treatment with a compound HR2 at neutral pH and 50-100 DEG C. The intermediate tetrachloro compound may be prepared by reacting cyanuric chloride with the disodium salt of 4-amino - 41 - (p - aminobenzoylamino) - stilbene-2,21-disulphonic acid. The latter compound may be prepared by condensing p-nitrobenzoylchloride with 4-amino-41-nitrostilbene-2,21-disulphonic acid, and reducing nitro to amino with iron and hydrochloric acid. In examples, compounds are prepared in which R1 and R2 are respectively: (1) -NHC6H5, -Cl; (2) -NHC6H5, -N(CH2CH2OH)2; (3) -NHC6H5, -NHC6H5; (4) -NH-CH2CH2OH, -OH; (5) -NH-C6H5-SO3H(m), -NHC6H5; (6) -NHC6H5, <FORM:0796524/IV (b)/2> ; (7) -NH-C6H5-OCH3, -N(CH2CH2OH)2; (8) -N(CH2CH2OH)2, -N(CH2CH2OH)2; (9) -NHC6H5, -NH2; (10) -NHC6H5, -NHCH3; (11) -NHCH2CH2OH, <FORM:0796524/IV (b)/3> (12) -N(CH3)(C6H5), -N(CH2CH2OH)2.ALSO:A compound of the general formula <FORM:0796524/IV (b)/1> where R1 is an amino group, or a residue of a primary or secondary amine which does not contain an auxochrome or a chromophore, and which is linked to the triazine ring through its nitrogen atom, and R2 is chlorine or hydroxyl, or has the same meaning as R1, or a watersoluble salt thereof such as an alkali-metal salt, may be applied to cotton and linen textiles or paper. The compound may be used in conjunction with known whitening agents which exhibit a bluish or violet fluorescence and may be incorporated in solid or liquid soaps or detergents.ALSO:New whitening agents, which may be incorporated in solid or liquid soaps or detergents, have the general formula <FORM:0796524/III/1> where R1 is an amino group, or a residue of a primary or secondary amine which does not contain an auxochrome or a chromophore, and which is linked to the triazine ring through its nitrogen atom, and R2 is chlorine or hydroxyl or has the same meaning as R1. The compounds and their water-soluble salts, such as alkali metal salts, exhibit a green fluorescence and may be used in conjunction with known whitening agents which exhibit a bluish or violet fluorescence.