Reactive azo dyes containing at least one haloacylaminomethyl group and processes for their production

The invention comprises water-soluble reactive azo dyes which contain at least one group of the formula -arylene-(CH2-NH-CO-R-Hal)n where R represents a divalent saturated or unsaturated aliphatic radical which may be substituted by halogen and possesses 1 to 3 carbon atoms, n represents one of the integers 1 or 2, Hal represents chlorine or bromine and arylene represents an arylene radical of the benzene or naphthalene series which may contain one or more alkyl or alkoxy groups with 1 to 5 carbon atoms and in addition one or more halogen atoms and is linked to the residue of the azo dye molecule either through a secondary or tertiary amino N atom or through the available N atom of a 5-pyrazolone ring and a process for the preparation thereof which consists in condensing in concentrated sulphuric acid, preferably of 85-100% strength or in concentrated phosphoric acid, at a temperature between 0 DEG and 30 DEG C. (a) a water-soluble monoaze or disazo dye having at least one aryl radical of the benzene or naphthalene series (which may contain one or more alkyl or alkoxy groups with 1 to 5 carbon atoms and in addition one or more halogen atoms) which is linked to the residue of the azo dye molecule either through a secondary or tertiary amino N-atom or through the available N atom of a 5-pyrazolone ring with (b) an N-halogenomethyl or N-hydroxymethyl derivative of an amide of a saturated or unsaturated chloro-or bromo-carboxylic acid containing 2 to 4 carbon atoms or the symmetrical ether corresponding to such N-hydroxymethyl derivative, the reactants being so chosen that the group -CH2N-CO-R-Hal enters into the said radical. In a modified process an azo dye intermediate is employed instead the azo dye (a) and after the condensation reaction, the condensation product is converted to an azo dye by a process involving an azo coupling reaction. The reactant (b) may be prepared by reacting formaldehyde, or a compound yielding formaldehyde on cleavage, and an amide of a saturated or unsaturated chloro- or bromocarboxylic acid containing 2 to 4 carbon atoms and may be used in the medium in which it is prepared. The dyes are suitable for dyeing, padding or printing wool, silk, synthetic polyamide fibres and fibres of natural and regenerated cellulose. Among the many examples relating to the preparation of mono-and disazo dyes are described processes in which the dye obtained by coupling diazotized 1-aminobenzene-2-sulphonic acid with 2-(21,41,61-trimethyl) - phenyla