Abstract: A process for preparing 2-(4'-aminophenyl) 5-amino benzimidazole, a known intermediate used in the synthesis of azo dyes, is disclosed wherein p-nitrobenzoic acid is condensed with aniline, and the N(4'-nitrobenzoyl) aniline produced is dinitrited to N(4'-nitrobenzoyl) 2,4-dinitroaniline; the latter is reduced to the corresponding triamine, which, upon cyclodehydration, results in the 2-(4'-aminophenyl) 5-amino benzimidazole.

Abstract: Liquid dyestuffs of the general formula: ##STR1## in which A and B each represent the residue of an aromatic benzene or naphthalene primary amine, possibly substituted by alkyl or alkoxy groups containing 1 to 2 carbon atoms, n represents 0 or 1, y represents 0 or 1, x and Z each represent a whole number such that the sum x + y + z is a whole number from 5 to 17, a process for the preparation of such dyestuffs in which there is coupled in aqueous medium the diazo derivative of an amine of the general formula:A - [N=N - B].sub.n -NH.sub.2in which A, B, n have the same significance as in claim 1, with a compound of the formula: ##STR2## in which x, y and z have the same significance as above, and the use of these dyestuffs for the coloration of petroleum products, inks, fats, waxes and plastics material.

Abstract: Liquid dyestuffs of the general formula: ##STR1## in which y represents 0 or 1, x and z each represent a whole number in which the sum x + y + z is a whole number from 5 to 17; a process for the preparation of such dyestuffs in which the bis-diazo derivative of bis-(4-amino-phenyl)-sulphide is coupled in aqueous medium with a 2-N-alkylamino-naphthalene of the formula: ##STR2## x, y and z having the same significance as above, in the proportion of two molecules of naphthalene derivative to one molecule of bis-diazo derivative; and the use of these dyestuffs for the coloration of petroleum products, inks, fats, waxes and plastics materials.

Abstract: Solution of ethylauramine hydrochloride in thiodiglycol; process for the preparation of such a solution in which dry ethylauramine hydrochloride, without water of crystallisation, is dissolved in thiodiglycol and process of colouration in which the colouring agent is such a solution.