- Fiber-reactive disazo brown dye having vinylsulfone-type reactive group
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A compound, or a salt thereof, represented by the following formula, STR1 wherein A is a substituted or unsubstituted phenylene or naphthylene group, B is STR2 in which R3 is a hydrogen atom or a lower alkyl, lower alkoxy, acylamino or ureido group, and R4 is a hydrogen atom or a lower alkyl or lower alkoxy group, R1 and R3 are independently a hydrogen atom or a substituted or unsubstituted lower alkyl group, X is a substituted or unsubstituted amino, lower alkoxy, substituted phenoxy or sulfo group, Y is --SO2 CH=CH2 or --SO2 CH2 CH2 Z, in which Z is a group capable of being split by the action of an alkali, and m is 2 or 3, which is useful for dyeing hydroxyl group- or amide group-containing fiber materials to give dyed products of a brown color having excellent fastness properties with good build-up property.
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- Process for the isolation of 1-naphthylamine-4,8-disulphonic acid
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Process for the isolation of 1-naphthylamine-4,8-disulphonic acid from sulphonation mixtures containing it according to which process the sulphonation mixture is introduced into preheated water in such a manner that, at the start of crystallization, a temperature of at least 100° C. is reached and the 1-naphthylamine-4,8-disulphonic acid is separated from the mother liquor at a temperature not higher than 70° C. The process is applied particularly advantageously for the isolation of 1-naphthylamine-4,8-disulphonic acid from sulphonation mixtures which have been obtained by introducing in turns alkali metal sulphate, 1-naphthylamine-8-sulphonic acid and SO3 into sulphuric acid which has been introduced initially, a total of 1.5 to 3 mols of SO3 and 0.6 to 1.5 mols of alkali metal sulphate being employed per mol of 1-naphthylamine-8-sulphonic acid.
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