METHOD FOR PREPARING DERIVATIVES OF 4,4'-DIAMINOSTILBENE-2,2'-DISULFOACID Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention describes method for preparing derivatives of 4,4'-diaminostilbene-2,2'-disulfoacid as stable aqueous solutions. Method involves interaction of cyanuric chloride with 4,4'-diaminostilbene-2,2'-disulfoacid and amine of the formula (II): wherein R means hydrogen atom, SO₃M, wherein M means sodium, potassium, mono-, di-, triethanolamine in an aqueous medium followed by isolation of the interaction product by effect with organic or inorganic acid at 50-90 C and conversion of free acid to solution by effect with inorganic base or ethanolamine at 60-80 C in the presence of carbamide, glycol and ethanolamine. Compounds are used as optical bleach agents in paper and pulp and textile industry. EFFECT: improved preparing method.2 cl