| abstract |
The present invention relates to a class of compounds of general formula (I) or their salts of general formula (II): n nIn formula (I)-(II), the substituents (A)p and (SO 3 H)n on the benzene ring are at the ortho, meta or para position, n is 0-2, and p is 0-3; M is selected from Li + , Na + , K + , NH 4 + or organic ammonium salt N + R 1 R 2 R 3 R 4 , where R 1 , R 2 , R 3 , R 4 are the same or different H, C 1-18 alkyl groups, cyclohexyl groups, CH 2 CH 2 OH, CH(CH 3 )CH 2 OH or benzyl groups; where p>0, A stands for the same or different groups selected from: H, CN, NO 2 , NH 2 , F, Cl, Br, C 1-18 alkyl group, cyclohexyl group, phenyl group, benzyl group, phenoxy group, C 1-18 alkoxy group, C 1-18 alkylthio group, SO 2 CH═CH 2 , SO 2 CH 2 CH 2 A 1 , NR 6 COR 5 or NR 6 SO 2 R 5 . |