Preparation of liquid formulations of basic azo dyes

A process for preparing liquid formulations of dyes of the general formula I

• where
• Y is chlorine or bromine,
• Z is hydrogen, chlorine, bromine, sulfonic ester, nitro or optionally substituted sulfamoyl,
• R is alkylene optionally interrupted by oxygen,
• m is 1 or 2,
• n is 0 or 1,
• p is 0, 1 or 2,
• An⊖ is the equivalent of an anion,
• R1 and R2 are independently hydrogen, optionally substituted alkyl, alkenyl, cycloalkyl, aralkyl or aryl or cominbe with the joining nitrogen to form a heterocycle,
• R3 is hydrogen or optionally substituted alkyl,
• B is hydrogen or C1- to C4-alkyl,
• B1 is hydrogen, hydroxyl, C1- to C4-alkoxy or C1- to C4-alkyl, where
• R4 is optionally substituted alkyl and
• R5 is hydrogen or C1- to C4-alkyl, and the radical
• may also be an optionally substituted piperazine radical, by diazotizing an amine of the formula II
• and then coupling the diazonium salt onto a compound of the formula III
• and also optionally adding solubilizing additives, which comprises effecting said diazotizing at a pH set to an acidic value using pure methanesulfonic acid or at least 20 mol % mixtures of methanesulfonic acid in monobasic acids.