There are described new blue to navy blue monoazo dyes of the general formula I ##STR1## in which X is chlorine, bromine or cyano, R is an unsubstituted or substituted alkyl group having 1 to 4 carbon atoms, R.sub.1 and R.sub.2 independently of one another are each an alkyl group which has 1 to 4 carbon atoms and which is unsubstituted or substituted by lower alkoxy, aryloxy or aryl, or an unsubstituted or substituted phenyl group, Y is lower alkyl or lower alkoxy, and n is an integer of at most 4; processes for producing them; and their use for dyeing and printing hydrophobic materials, especially aromatic polyesters, the resulting dyeings being level deep and reproducible, while additionally distinguished by good general fastness properties.

The invention relates to valuable new blue to navy blue monoazo dyes of the 
general formula I 
##STR2## 
in which X is chlorine, bromine or cyano, R is an unsubstituted or 
substituted alkyl group having 1 to 4 carbon atoms, R.sub.1 and R.sub.2 
independently of one another are each an alkyl group which has 1 to 4 
carbon atoms and which is unsubstituted or substituted by lower alkoxy, 
aryloxy or aryl, or an unsubstituted or substituted phenyl group, Y is 
lower alkyl or lower alkoxy, and n is an integer of at most 4; and also to 
the production and use of the new dyes. 
The terms `lower alkyl and lower alkoxy` relate to alkyl or alkoxy groups 
having 1 to 4, preferably 1 or 2, carbon atoms, such as methyl, ethyl, 
methoxy or ethoxy. 
R, R.sub.1 and R.sub.2 as an alkyl group having 1 to 4 carbon atoms can be 
both straight-chain and branched-chain. They are, independently of one 
another, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 
sec-butyl or tert-butyl. These alkyl groups can be substituted, for 
example in the case of R by halogen, such as bromine or particularly 
chlorine, CN, lower alkoxy, especially methoxy or ethoxy, or aryloxy, 
particularly phenoxy; or in the case of R.sub.1 and R.sub.2 by lower 
alkoxy, especially methoxy and ethoxy, aryloxy, particularly phenoxy, or 
aryl, especially phenyl. For R there may be mentioned in particular 
methyl, ethyl, methoxymethyl and phenoxymethyl; and for R.sub.1 and 
R.sub.2 in particular methyl, ethyl, propyl, isopropyl, methoxyethyl, 
phenoxyethyl, benzyl and phenethyl. As a substituted phenyl group, R.sub.1 
and R.sub.2 can be for example tolyl or chlorophenyl. 
X is preferably chlorine or bromine. R is preferably unsubstituted alkyl, 
especially ethyl and in particular methyl. R.sub.1 is preferably 
isopropyl, ethyl or methoxyethyl and especially methyl. R.sub.2 is 
preferably lower alkyl or lower alkoxyalkyl, particularly methyl, ethyl, 
methoxyethyl or ethoxyethyl. Y is preferably methyl or ethyl. n is 
preferaly 1 or 2, especially 1. In preferred monoazo dyes of the formula 
I, X is chlorine or bromine, R, R.sub.1 and Y independently of one another 
are methyl or ethyl, R.sub.2 is as defined under the formula I, and n is 1 
or 2. 
Preferred monoazo dyes of the formula I are in particular those in which X 
is chlorine or bromine, R, R.sub.1 and Y independently of one another are 
methyl or ethyl, R.sub.2 is methyl, ethyl, methoxyethyl or ethoxyethyl, 
and n is 1. 
Dyes of the formula (I) are obtained by a process wherein diazo components 
of amines of the general formula II 
##STR3## 
are coupled with coupling components of the general formula III, in the 
p-position with respect to the amino group: 
##STR4## 
in which X, R, R.sub.1, R.sub.2, Y and n are as defined under the formula 
I. 
The diazo components of the formula II are known, and can be obtained by 
processes known per se. The coupling components of the formula III are 
new, and can be obtained for example by condensation of a ketone of the 
formula 
##STR5## 
with an amine of the formula 
##STR6## 
in which R, R.sub.1, R.sub.2, Y and n are as defined under the formula I, 
with subsequent reduction of the condensation product. 
the diazotisation of the diazo components mentioned is performed in the 
customary manner, preferably with the aid of a solution of 
nitrosylsulfuric acid in concentrated sulfuric acid. 
The coupling can likewise be performed in a manner known per se, for 
example in a neutral or advantageously acid aqueous solution or 
suspension. 
After coupling has been effected, the formed dyes can be readily separated 
from the coupling mixture, for example by filtration, since they are 
virtually insoluble in water. 
According to the invention, there is suggested in addition an alternative 
process for producing the dyes of the invention, which process comprises 
treating the corresponding dye of the formula I, in which --COY denotes a 
hydrogen atom, with an acylating agent. Examples of acylating agents are 
acetic anhydride, acetyl chloride or propionyl chloride. This alternative 
process is advantageously performed by reacting the reactants in the 
presence of a base, for example pyridine. 
The new monoazo dyes are excellently suitable for dyeing and printing 
hydrophobic materials, for example those made from polyamides, in 
particular however textiles or fibres made from aromatic polyesters, such 
as polyethylene glycol terephthalate, or condensation products from 
terephthalic acid and 1,4-(bis-hydroxymethyl)-cyclohexane or cellulose 
triacetate. The monoazo dyes according to the invention have in particular 
very good dyeing and build-up properties on aromatic polyester textile 
materials, in consequence which it is possible to obtain with uniformly 
defined monoazo dyes level, deep and reproducible shades. 
The blue to navy blue dyeings and printings obtained on the stated 
materials with the said dyes are distinguished by a good colour in 
artificial light and good colouring strength, and by good general fastness 
properties, especially good pH stability, and good fastness to sublimation 
and to light. 
Dyeing with the dyes of the formula I is performed by introducing the 
material to be dyed into an aqueous dispersion of the dyes, preferably at 
elevated temperatures, for example at 40.degree. C.; optionally adding 
customary auxiliaries, such as sulfite cellulose degradation products, 
condensation products from higher alcohols with ethylene oxide, polyglycol 
ethers of fatty acid amides or alkylphenols, and so forth, and then 
preferably adding to the bath acid agents, for example organic acids such 
as formic acid or acetic acid, or inorganic acids such as phosphoric acid. 
The bath is subsequently heated to the optimum dyeing temperature, 
preferably, depending on the type of fibre materials to be dyed, to a 
temperature of between 70.degree. and 140.degree. C. Dyeing is performed 
at this temperature until the desired depth of colour is obtained. After 
cooling of the bath, the dyed fibre material can be subjected to an 
aftertreatment, for example in the case of acetate fibres to an 
aftertreatment with soaps, or in the case of fibres formed from aromatic 
polyesters to a reductive aftertreatment with the addition of alkali. 
When aromatic polyesters or triacetate fibres are dyed at a temperature of 
105.degree. C., it is generally advantageous to concomitantly use 
customary carrier substances, such as mono-, di- or trichlorobenzene, 
benzoic acid, salicylic acid, o- and p-phenylphenol or benzyl alcohol. 
Printing is likewise carried out in a manner known per se by applying to 
the materials a printing paste containing the dye(s) and the customary 
auxiliaries, and subsequently subjecting the printings to a heat 
treatment. 
The claimed dyes are superior to the nearest comparable dyes by a better 
fastness to boiling and better substantivity in the dyeing of polyester 
materials.