Azo dyes are obtained by introducing into any azo-body at least one group of the type <FORM:0422843/IV/1> in which R1=H, alkyl, aralkyl, acidyl or the group --R2--O--R3, R2=an aliphatic hydrocarbon radicle consisting of at least two carbon atoms, and R3=alkyl, aralkyl, alkylene, alkoyl, aralkoyl or aroyl. Alkyl includes derivatives, e.g. C2H4Cl, C2H4NMe2, C2H4SO3H &c. The process consists in: (1) coupling an aromatic diazo compound with a coupling component containing at least one alkyl-, aralkyl- or alkylene-oxyalkylamino group, or an alkoyl-, aralkoyl- or aroyl-oxyalkylamino group; (2) by reaction of a dyestuff containing a primary or secondary amino-group with an ether or an organic ester of an alcohol, which contains at least one group capable of reacting with the --NH2 or ---NHX group of the dyestuff, X meaning alkyl, aralkyl or acidyl; (3) by etherifying or esterifying with an organic acid or dyestuff containing an o -oxyalkylamino group. According to the components chosen they dye wool, silk, cotton, regenerated cellulose, cellulose esters or ethers, paper, lacquers and varnishes and may be used as pigments. The insoluble dyestuffs, which are especially suitable for dyeing cellulose esters and ethers, may be ground with dispersing agents to form dyestuff preparations. In examples, the following dye-stuffs are described: (1)--(6) and (8)--(10) p-nitraniline, 5-nitro-2-anisidine, 2-chlor-4-nitraniline, sulphanilic acid or 2 : 6-dichlor-4-nitraniline --> b - [(ethylphenyl) - amino] - - ethylmethylether or ethyl - (o - acetoxyethyl) - aniline (red to bordeaux-red); (7) 2 : 4-dinitraniline --> b - [(2 - methoxy - 5 - methyl)-phenylamino] - ethylmethylether. Examples of the dyeing process for acetate artificial silk are also given. Samples have been furnished under Sect. 2 (5) of the following dyestuffs: (1) and (2) p-nitraniline or 2-chlor-4-nitraniline --> [di - (o - methyloxyethyl)] - aminobenzene; (3) and (4) p-nitraniline or 2 : 4-dinitraniline --> 5-methyl-2-methoxy-1-[di-(o -methyloxyethyl]-aminobenzene; (5) 6-chlor-2 : 4-dinitraniline ---> 1-methyloxyethylaminonaphthalene. Other components specified are aniline, toluidines, nitranilines, chloranilines or their sulphonic or carboxylic acids, e.g. metanilic acid, nitrochloranilines, anisidines, nitro- and chloro-anisidines, dinitranilines, dinitrochloranilines, o-aminophenol and its derivatives, e.g. o-aminocresols, nitroaminophenols, e.g. 5-nitro-2-aminophenol, chloraminophenols and their sulphonic acids, naphthylamines and their sulphonic acids, aminoazobenzene and its derivatives, e.g. aminoazotoluenes and aminazobenzenesulphonic acids; b - (phenylamino) - ethylmethylether, b - (phenylamino) - diethylether, b - [(methylphenyl) - amino] - ethylmethylether or-diethylether, b - [(ethylphenyl)amino] - diethylether, b - [(5 - methyl) - phenylamino] - ethylmethyl - ether diethylether, b -[(2-methoxy-5-methyl)-phenylamino] - diethylether, b - [(2 : 5 - dimethoxy) - phenylamino] - ethylmethylether or -diethylether, b - [{(2 - methoxy - 5 - methyl or methoxy) - phenylethyl} - amino] - ethyl - methylether or -diethylether, (o -acetoxyethyl)-aniline, (o - acetoxyethyl) methyl- or -ethyl-aniline and (o - acetoxyethyl) - toluidines or anisidines. The following additional combinations (acetate artificial silk dyes) are also specified: aniline or p-nitraniline ---> b -(phenylamino) - ethylmethylether or -diethylether or (o - acetoxyethyl) - aniline, (yellow to orange red); 5-nitro-2-aminophenol, 4 : 6-dinitro-o-anisidine or 2 : 4-dinitraniline ---> b - [(2 - methoxy - 5 - methyl) - phenylamino] - ethylmethylether or b -[(2 : 5 - dimethoxy) - phenylamino] -ethylmethylether (red violet to violet brown). Arylaminoalkylethers are made (1) by condensing the corresponding amine, e.g. aniline, ethylaniline or 1-amino-2-methoxy-5-methyl-benzene with an ether of a polyhydric alcohol which contains at least one non-etherified OH group or with a sulphuric acid ester or dialkyl ether sulphate or arylsulphonic ester thereof, e.g. the p-toluenesulphonic ester of glycolmonomethyl- or ethyl ether (from the glycol ether and p-toluenesulphochloride); (2) by condensing a halogen-ether with the amine; (3) by etherifying the corresponding arylaminoalcohol; (4) by causing an arylaminohalogenalkyl compound to react with an alcoholate; (5) by causing an aryl compound which contains in the nucleus a substituent capable of reacting (e.g. a halogen in o-position to a nitro group), to react with an aminoalkylether. Thus b - [(ethylphenyl) - amino] - ethylmethyl ether is made from ethylaniline and the p-toluenesulpho ester of glycol monomethylether or by etherifying ethyl-(o -oxyethyl)-aniline by means of a methylhalide and sodium; b - [(2 - methoxy - 5 - methyl) - phenylamino] - ethylmethylether may be similarly made from 1-amino-2-methoxy-5-methylbenzene. The di-(o -methyloxyethyl) compounds required in the preparation of the samples are also prepared in the same manner. Esters of arylaminoalcohols with organic acids are made (1) by condensing the corresponding amine with an organic ester of a polyhydric alcohol, which contains at least one non-esterified OH group, or with sulphuric acid esters or arylsulphonic acid esters thereof; (2) by condensing an organic ester of a halogenated alcohol with the amine; (3) by esterifying the corresponding arylaminoalcohol; (4) by causing an arylaminohalogenalkyl to react with the salt of an organic acid; (5) by reaction between an aryl compound which contains in the nucleus a substituent capable of reaction, e.g. a halogen in o-position to a nitro group, and an organic ester of an amino-alcohol. Thus (acet-o -oxyethyl)-ethylaniline is made from o -oxyethyl-aniline and acetic anhydride in presence of sodium acetate. The Specification as open to inspection under Sect. 91 comprises also the condensation of an azo dyestuff which contains a primary or secondary amino group with a hydrogen halide ester, an arylsulphonic acid ester or sulphonic acid ester of a polyhydric alcohol containing at least one esterified group. In the case of the corresponding ethers [cf. (2) above], the following compounds are specified: <FORM:0422843/IV/2> <FORM:0422843/IV/3> or homologues thereof. In respect of o -oxyalkylamino dyestuffs it is stated that these are obtainable by means of compounds such as Cl.CH2CH2OH, Br--[CH2]3 OH, I--CH2(CHOH)--CH3, Br--[CH2]3--CH (OH)CH3. Dyes containing o -halogenalkylamino groups, e.g. --NH--CH2.CH2Br or --NH--[CH2]3--Br may be treated with an alcoholate or the salt of an organic acid, e.g. sodium formate or acetate. Further components specified are 1 : 8-aminonaphthol sulphonic acids, e.g. H acid or toluene sulphonic acids thereof, aminoazo dyestuffs, e.g. aniline or naphthylamine sulphonic acids ---> aniline, cresidine, a -naphthylamine and its 6- or 7-sulphonic acids and 1-amino-2-methoxynaphthalene; (o -acetoxyethyl)-methyl-toluidines or anisidines, [di(o -ethyloxymethyl)]-aniline, [di-(o - acetoxyethyl)] - aniline, 1 - [(ethyl - oxy - methyl - )amino] - naphthalene, 2 - [(ethyloxy - methyl-)-amino]-naphthalene, <FORM:0422843/IV/4> (obtained by alkylating m-nitraniline and reducing) and the corresponding OH compound (obtained by Sandmeyers reaction). Dyestuffs are also specified in which the group <FORM:0422843/IV/5> is in the diazo component. Aminoazo dyes of the general formula <FORM:0422843/IV/6> e.g. 4 - amino - 4<1> - (ethyl - ethyloxy - methyl)-, 4 - amino - 4<1> - (diethyloxymethyl)-, 4 - amino-4<1>-(o -oxyethyl-ethyl-oxymethyl)-or 4-amino-4<1>-(ethyl-o -acetoxyethyl) - aminoazobenzene, may be diazotized and used for developing cotton which has been prepared with arylides of 2 : 3-oxynaphthoic acid, 2 : 3-oxyanthracene-carboxylic acid, and hydroxycarbazole- or hydroxybenzocarbazolecarboxylic acids; aminoazo compounds of the type <FORM:0422843/IV/7> may also be used. Sulphonated dyestuffs for wool, silk and cotton may be prepared from sulphanilic acid, nitraniline and dehydrothiotoluidine sulphonic acids. 4-Amino-1-[ethyl-ethyloxymethyl] - aminobenzene (obtained by treating [ethyl-ethyloxymethyl]-aminobenzene or [b - (methylphenyl) - amino] - ethylmethyl ether with nitrous acid and reducing) gives blue dyes when diazotized and coupled with periderivatives of naphthalene, e.g. 1 : 8-dioxy-naphthalene or a 1 : 8-aminonaphthol sulphonic acid; if the diazo component contains halogen or SO2--aryl groups, N-acidyl derivatives of 1 : 8-aminonaphthol sulphonic acids may be used as coupling components. Blue dyes are also obtained by hydrolyzing the dyestuffs obtained by coupling N-acidyl derivatives of 4 - diazo - 1 - (mono - ethyloxymethyl) - amino - benzene with 1 : 8-dioxynaphthalene-4- or 3 : 6-disulphonic acid; the acetyl and nitroso compounds are specified as acidyl derivatives. Disazo and polyazo dyes are also specified, e.g. the dyestuff N-(ethyl-methoxyethyl)-aminobenzene \sM benzidine --> H acid \sM p-nitraniline, primary disazo dyes from m-phenylene diamine and aminonaphthol derivatives, and secondary disazo dyes from the aminoazo dye 1-naphthylamine-6-sulphonic acid --> 1 - naphthylamine - 6 - sulphonic acid. In examples, the following dyes are described: (1) 6-chlor-2 : 4-dinitraniline or H acid --> 1-(mono-ethyloxyethyl)aminonaphthalene; (2) 1-methyl-3<1>-amino - 5<1> - sulphonic acid- 4 : 4<1>-diphenylsulphone --> [b -(ethylphenyl)-amino]-ethylmethylether or the product of reaction of p-toluenesulphonic ester and glycol monomethylether with b -naphthylamine; (3) p-cresolester of p-nitraniline-o-sulphonic acid, which is sulphonated in the cresol nucleus --> [b -(ethylphenyl)-amino]-ethylmethylether; (4) cotton is impregnated with the o-anisidide of 2 : 3-oxynaphthoic acid and developed with diazotized 4 - amino - 3 - chloro - 6 - methoxy - 4<1> - [(ethylethyloxymethyl) - amino] - azobenzene or the dyestuff may be produced in substance;