GB2146652A

GB2146652A - Red monoazo disperse dyes

Info

Publication number: GB2146652A
Application number: GB08419607A
Authority: GB
Inventors: John Frederic Dawson; Malcolm Stewart Jackson; Keith Bramham; John Michael Wyles
Original assignee: Yorkshire Chemicals Ltd
Current assignee: Yorkshire Chemicals Ltd
Priority date: 1983-09-16
Filing date: 1984-08-01
Publication date: 1985-04-24
Also published as: GB8324810D0; GB8419607D0; GB2146652B

Abstract

Monoazo disperse dyes of general formula:- <IMAGE> wherein R<1> and R<2> each independently represent an alkyl group such that the sum of their carbon atoms must total at least three, R<3> is an alkyl group, and n is 2 or 3; mixtures of two or more such dyes; processes for the preparation of the dyes and the mixtures; and processes for dyeing or printing hydrophobic fibres with the dyes or the mixtures.

Description

SPECIFICATION Red monoazo disperse dyes In the dyeing of hydrophobic fibres, especially polyester fibres, with disperse dyes, bright bluish red were for many years obtained by use of dyes of the anthraquinone series, of which C.l. Disperse Reds 60,92,132,146 and 159 may be cited as examples.

More recent work has described monoazo dyes which closely approach the hue and brightness of these anthraquinone dyes and offer considerable advantages in economy over the latter. They frequently show advantages also in light fastness in heavy shades and in wet fastness.

We have found that dyes of general formula:

where R is an alkyl group, have the desired properties, but unfortunately possess comparatively poor build up.

We were surprised to find that by replacing at least one of the two methyl groups in the above with an alkyl group containing at least two carbon atoms, the build up was significantly improved.

According to the present invention therefore, there are provided monoazo disperse dyes of general formula:

wherein R1 and R2 each independently represent an alkyl group such that the sum of their carbon atoms must total at least three, R3 is an alkyl group and n is 2 or 3 The preferred dyes are those in which each of the alkyl groups R1, R2 and R3 contain 1-5 carbon atoms.

Specially preferred dyes are those in which the alkyl groups R1 and R2 each contain 1-3 carbon atoms and the alkyl group R3 contains 2-5 carbon atoms.

Also according to the present invention there are provided mixtures of two or more monoazo disperse dyes of general formula II as defined above.

The preferred dyes present in the mixtures claimed above are those in which each of the alkyl groups R1, R2 and R3 contain 1-5 carbon atoms. Specially preferred dyes in these mixtures are those in which the alkyl groups R1 and R2 each contain 1-3 carbon atoms and the alkyl group R3 contains 2-5 carbon atoms.

It is further preferred that the dyes in these mixtures differ in respect of the values of only one of the groups R1, R2 and R3. It is still further preferred that they differ in respect of the values of group R' only.

It is understood that the term "alkyl" groups refers to both straight and branched chain alkyl groups.

The invention also provides a process for the preparation of dyes of general formula 11 in which a compound of general formula:

wherein R', R2, R3 and n have the meanings given above and R4 and R5 each represents a chlorine, bromine or iodine atom, is reacted with a metal cyanide, whereby the groups R4 and R5 are replaced by cyanide groups.

This is a nucleophilic replacement reaction which is known and is described, for example, in BP 1,125,683.

The preferred compounds of general formula III are those in which R4 and R5 represent bromine atoms.

The preferred dyes of general formula Ill are those in which each of the alkyl groups R1, R2 and R3 contain 1-5 carbon atoms. Specially preferred dyes are those in which the alkyl groups R' and R2 each contain 1-3 carbon atoms and the alkyl group R3 contains 2-3 carbon atoms.

The compounds of general formula Ill may be obtained for example by the diazotisation of an amine of general formula:

and coupling the resultant diazonium compound to a coupling component of general formula:

wherein R1, R2, R3, R4, R5 and n have the meanings given above.

The invention further provides a process for the preparation of a mixture of two of more dyes of general formula 11 in which a mixture of two or more intermediate compounds of general formula III, in which Ra, R2, R3, R4, R5 and n have the meanings given above, are reacted with a metal cyanide, whereby the groups R4 and R5 are replaced by cyanide groups.

The mixture of compounds of general formula Ill may be prepared by the physical admixture of compounds of general formula Ill or by coupling in admixture the diazonium salts of one or more amines of general formula IV with one or more coupling components of general formula V. Where a mixed coupling process is used it is usually based on a mixture of diazo components coupled to a single coupler or on a mixture of couplers coupled to a single diazo component. In a preferred process a mixture of the diazonium salts of two or more amines of general formula IV are coupled to one coupling component of general formula V.

Mixtures of dyes of general formula 11may also be prepared by physical admixture of the dyes after preparation as individual products.

Specific examples of the amines of general formula iV which may be used for preparing the diazo compounds are: 2,6-dibromo-4-methylaniline 2,6-dibromo-4-ethylaniline 2,6-dibromo-4-propylaniline 2,6-dibromo-4-isopropylaniline 2,6-dibromo-4-butylaniline 2,6-dibromo-4-sec-butylaniline 2,6-dibromo-4-tert-butylaniline 2,6-dibromo-4-amylaniline Specific examples of amines of general formula V which may be used as coupling components are:: N-2-cyanoethyl-N-ethyl-3-acetylaminoaniline N-2-cyanoethyl-N-propyl-3-acetylaminoaniline N-2-cyanoethyl-N-butyl-3-acetylaminoaniline N-2-cyanoethyl-N-3-methylbutyl-3-acetylaminoaniline N-2-cyanoethyl-N-amyl-3-acetyiaminoaniline N-2-cyanoethyl-N-ethyl-3-propionylaminoaniline N-2-cyanoethyl-N-propyl-3-propionylaminoaniline N-2-cyanoethyl-N-butyl-3-propionylaminoaniline N-2-cyanoethyl-N-amyl-3-propionylaminoaniline N-2-cyanoethyl-N-3-methylbutyl-3-propionylaminoaniline N-2-cyanoethyl-N-ethyl-3-butyrylaminoaniline N-2-cyanoethyl-N-propyl-3-butyrylaminoaniline N-2-cyanoethyl-N-butyl-3-butyrylaminoaniline N-2-cyanoethyl-N-amyl-3-butyrylaminoaniline N-2-cyanoethyl-N-3-methyl butyl-3-butyrylam inoanil ine N-2-cyanoethyl-N-ethyl-3-valerylaminoaniline N-2-cyanoethyl-N-propyl-3-valerylaminoaniline N-2-cyanoethyl-N-butyl-3-valerylaminoaniline N-3-cyanopropyl-N-ethyl-3-acetylaminoaniline N-3-cyanopropyl-N-propyl-3-acetylaminoaniline N-3-cyanopropyl-N-butyl-3-acetylaminoaniline N-3-cyanopropyl-N-ethyl-3-prnpionylaminoaniline N-3-cyanopropyl-N-ethyl-3-butyrylaminoaniline N-2-cyanoethyl-N-ethyl-3-isobutyrylaminoaniline N-2-cyanoethyl-N-isopropyl-3-acetylaminoaniline N-2-cyanoethyl-N-3-methyl butyl-3-acetylaminoaniline N-3-cyanopropyl-N-isopropyl-3-acetylaminoaniline N-3-cyanopropyl-N-isopropyl-3-propionylaminoaniline N-2-cyanoethyl-N-isopropyl-3-propionylaminoaniline N-2-cyanoethyl-N-3-methyl butyl-3-propionylaminoaniline The invention further includes a process for the dyeing and printing of hydrophobic fibres, particularly polyester fibres with disperse dyes or mixtures of disperse dyes of general formula II.

Specific examples of hydrophobic fibres are cellulose acetate fibres such as secondary cellulose acetate and cellulose triacetate, polyamide fibres, polyacrylonitrile fibres such as "COURTELLE" ("COURTELLE" is a Registered Trade Mark), and in particular polyester fibres such as "TERYLENE" ("TERYLENE" is a Registered Trade Mark).

The dyes are preferably dispersed by grinding with water and a suitable dispersing agent, e.g. Dyapol PHS.

Dyeing may be carried out on polyester fibres from an aqueous bath at 95-140"C optionally in the presence of a carrier, for example, an emulsion of 2-phenylphenol such as that sold as "Optinol B". Alternatively the dye dispersion may be thickened with sodium alginate or otherthickeners commonly used in textile printing and applied to polyester fabrics in the usual way by padding or printing with a roller or through a screen. After drying the fabric, the dye is fixed, for example by steaming, at 1.0 to 1.7 bar pressure or by heating the fabric in dry air at 160-220"C for 30 to 90 seconds or by heating at 170-1800C for 4 to 8 minutes with high temperature (superheated) steam.The dyes may also be applied by dyeing or printing on to a secondary cellulose acetate, polyamide and polyacrylonitrile fibres by the typical methods of application to these fibres described in the Colour Index, Third Edition, 1971 and its supplements, 1975 and 1982 (published by the Society of Dyers and Colourists, Bradford, England).

We have found that there are advantages in having mixtures of two or more compounds of General Formula II since such mixtures have superior dyeing properties to those of the individual components of such a mixture. These superior dyeing properties are demonstrated by the dye mixtures dyeing more rapidly and being less sensitive to variations in dyeing temperature than are the individual components of the mixture alone. This means that these mixtures are much less affected by processing variables than the individual components of the mixtures alone and so enable excellent reproducibility of dyeings from batch to batch.

In heavy depths, the improved dyeing rate of the mixtures ensures maximum exhaustion in economic times, which apart from the saving in time, further ensures maximum reproducibility from batch to batch.

With the single components, maximum exhaustion in heavy depths may only be obtained by prolonged and uneconomic dyeing times.

The dyes of the present invention provide bright red shades of good general fastness properties with good build up properties.

The invention will be more clearly understood by reference to the following Examples in which parts and percentages are by weight unless otherwise stated.

Example 1 21.4 parts of 3-propionylamino-4-(2,6-dibromo-4-methyl-phenylazo)-N-2-cyanoethyl-N-propylaniline, prepared as in Preparation 1 is added to 100 parts dimethylformamide and to this are added 4.7 parts of zinc cyanide and 0.4 parts copper cyanide.

The mixture is warmed to 100"C and maintained at this temperature until thin layer chromatography shows the reaction to be completed. After cooling to room temperature the reaction mixture is added to water containing sodium perborate. After stirring for several hours the dye of formula

is filtered off, washed and dried.

Preparation 1 6.9 parts of sodium nitrite are added with stirring to 70 parts of 100% sulphuric acid, the temperature being held at 30"C by external cooling. The temperature is then raised to 70"C before cooling to 300C. 26.5 parts 2,6-dibromo-4-methylaniline are then added during 30 minutes and the mixture stirred for three hours at this temperature. The diazo solution so obtained is added to a solution prepared by adding the mixture containing 25.9 parts N-2-cyanoethyl-N-propyl-3-propionylamino-aniline prepared as in Preparation 2 below in 10 parts of 100% sulphuric acid and 500 parts of iced water at 0 C. The pH is maintained at 3-4 during coupling by the addition of anhydrous sodium acetate.The mixture is stirred for one hour and the dye which has the formula:

is filtered off, washed well with water and dried.

Preparation 2 The N-2-cyanoethyl-N-propyl-3-propionylaminoaniline used in Preparation 1 may be prepared as follows.

A mixture of 21.7 parts N-2-cyanoethyl-3-propionylaminoaniline, 12.3 parts 3-bromopropane and 4.3 parts sodium carbonate in 80 parts ethanol is reluxed, more 3-bromopropane and sodium carbonate being added if necessary until TLC shows the reaction to be complete. The mixture is filtered to remove the inorganic material and the filtrate used in the method described in Preparation 1.

Example 2 If the 21.4 parts of 3-propionylamino-4-(2,6-dibromo-4-methylphenylazo)-N-2-cyanoethyl-N-propylaniline used in Example 1 is replaced by 21.4 parts of 3-acetylamino-4-(2,6-dibromo-4-ethylphenylazo)-N-2cyanoethyl-N-propylaniline the dye formed has the formula:

Example 3 One part of the dye prepared in Example 1 is added to 18 parts of water and 2 parts of Dyapol PHS and milled in a ball mill until the average particle size of the dye is reduced to 1.5 Fm.

20 parts of the resultant aqueous dispersion is diluted to 1000 parts with water to form a dyebath. 100 parts of polyester yarn are introduced into the dyebath at room temperature and the temperature is then raised to 1300C and maintained for one hour in a pressurised dyeing machine. After this time the yarn is removed, rinsed and dried. The polyester fibres are dyed bright red shades possessing good light, wet processing and sublimation fastness together with good build up properties.

Example 4 One part of the dye prepared in Example 2 is added to 18 parts of water and 2 parts of Dyapol PHS and milled in a ball mill until the average particle size of the dye is reduced to 1-5 ym.

20 parts of the resultant aqueous dispersion is added to a mixture of 5 parts of a galactomannan thickening agent, such as that sold as "Indalca PA 3" and 5 parts of urea in 50 parts of water for form a paste which is then printed through a screen onto polyester fabric. After drying, the print is fixed by steaming for 20 minutes at 1.4 bar pressure. After this time the fabric is removed, washed and dried. The bright red print has good fastness to light and washing.

Example 5 If the 21.4 parts of 3-propionylamino-4-(2,6-dibromo-4-methylphenylazo)-N-2-cyanoethyl-N-propylaniline used in Example 1 is replaced buy a mixture comprising 10.42 parts 3-acetylamino-4-(2,6-dibromo-4 ethylphenylazo)-N-2-cyano-ethyl-N-ethylaniline and 10.98 parts 3-acetylamino-4-(2,6-dibromo-4ethylphenylazo) N-2-cyano-ethyl-N-butylaniline the dye mixture obtained has the following formula::

The mixture of intermediate compounds of general formula V used to prepare the dye mixture of formula IX may be formed by mixing the individual intermediate compounds or alternatively by coupling a mixture of the appropriate coupling components - viz - N-2-cyano-ethyl-N-ethyl-3-acetylaminoaniline and N-2cyanoethyl-N-butyl-3-acetylaminoaniline to diazotised 2,6-dibromo-4-ethylaniline.

Example 6 One part of the product from Example 5 is treated according to the process of Example 3. The resulting dyed polyester fibres are brighter red and have good fastness properties.

In the following table data is given referring to other monoazo dyes of the present invention corresponding to the general formula II which may be prepared and used in accordance with the general methods described in the preceding examples.

Example R1 R2 Rs CnH2n Shade on polyester Fibres 7. CH3 CH2CH3 (CH2)3CH3 C2H4 Red 8 CH3 CH2CH3 (CH2)2CH(CH3)CH3 C2H4 9 CH3 (CH2)2CH3 CH2CH3 C2H4 10 CH3 (CH2)2CH3 (CH2)3CH3 C2H4 11 CH3 (CH2)3CH3 CH2CH3 C2H4 12 CH2CH3 CH3 (CH2)4CH3 C2H4 13 CH2CH3 CH3 (CH2)5CH3 C2H4 14 (CH2)2CH3 CH3 CH2CH3 C2H4 15 (CH2)2CH3 CH3 CH2CH2CH3 C2H4 16 (CH2)2CH3 CH3 (CH2)3CH3 C2H4 17 (CH2)2CH3 CH2CH3 CH2CH3 C2H4 18 (CH2)2CH3 CH2CH3 CH2CH2CH3 C2H4 19 (CH2)2CH3 CH2CH3 (CH2)3CH3 C2H4 20 (CH2)2CH3 CH2CH3 (CH2)2CH(CH3)2 C2H4 21 (CH2)2CH3 (CH2)2CH3 CH2CH3 C2H4 22 (CH2)2CH3 (CH2)2CH3 (CH2)3CH3 C2H4 23 CH(CH3)CH3 CH3 CH2CH3 C2H4 24 CH(CH3)CH3 CH3 (CH2)2CH3 C2H4 25 CH(CH3)CH3 CH3 (CH2)3CH3 C2H4 26 CH(CH3)CH3 CH2CH3 CH2CH3 C2H4 27 CH(CH3)CH3 CH2CH3 (CH2)3CH3 C2H4 28 CH(CH3)CH3 (CH2)2CH3 C2H5 C2H4 29 CH(CH3)CH3 (CH2)2CH3 (CH2)2CH3 C2H4 30 CH(CH3)CH3 CH3 CH2CH3 C2H4 31 CH(CH3)CH3 CH2CH3 CH2CH3 C2H4 32 CH2CH(CH3) CH3 (CH2)2CH3 C2H4 33 CH2CH(CH3)2 CH3 (CH2)3CH3 C2H4 34 C(CH3)3 CH3 CH2CH3 C2H4 35 C(CH3)3 CH2CH3 CH2CH3 C2H4 36 CH3 CH2CH3 CH2CH3 C3H6 37 CH3 (CH2)2CH3 CH2CH3 C3H6 38 CH2CH3 CH3 CH2CH3 C3H6 39 CH2CH3 CH2CH3 CH2CH3 CH5 40 CH2CH3 (CH2)2CH3 CH2CH3 C3H6 41 CH2CH3 (CH2)3CH3 CH2CH3 C3H6 Example 42 6.9 parts of sodium nitrite are added with stirring to 70 parts of 100% sulphuric acid, the temperature being held at 30"C by external cooling. The temperature is then raised to 700C before cooling to 30DC. 27.9 parts 2,6-dibromo-4-ethylaniline are added during 30 minutes and the mixture stirred for three hours at this temperature. The diazo solution so obtained is added to a solution of 23.1 parts N-2-cyanoethyl-N-ethyl-3 acetylaminoaniline in 10 parts of 100% sulphuric acid and 500 parts of iced water at 0 C. The pH is maintained at 3-4 during coupling by the addition of anhydrous sodium acetate. The mixture is stirred for one hour and the product filtered off, washed well with water and dried.

20.8 parts of the above product is added to 100 parts of dimethylformamide and to this are added 4.7 parts of zinc cyanide and 0.4 parts of copper cyanide.

The mixture is warmed to 100"C and maintained at this temperature until thin layer chromatography shows the reaction to be complete. After cooling to room temperature the reaction mixture is added to water containing sodium perborate. After stirring for several hours, the dye of formula:

is filtered off, washed and dried.

Example 43 One part of the dye from Example 42 is added to 18 parts of water and 2 parts of Dyapol PHS and milled in a ball mill until the average particle size is reduced to 1-2 Fm.

When the above dispersion is used to dye polyester fibres according to the method described in Example 2, bright red shades are obtained which have good light, wet processing and sublimation fastness.

This dye shows excellent build up on polyester fibres, but if in Example 42, the 2,6-dibromo-4-ethylanilene is replaced by 2,6-dibromo-4-methylaniline, (ie. a dye of general formula 1), the resultant dye shows inferior build up.

Example 44 If in the above Example 42 the 27.9 parts of 2,6-dibromo-4-ethylaniline is replaced by a mixture of 14.0 parts of 2,6-dibromo-4-ethylaniline and 14.7 parts 2,6-dibromo-4-isopropylaniline, the resulting mixture has the following formula:

where R is a mixture of ethyl and iso-propyl.

Example 45 One part of the product from Example 44 is added to 18 parts of water and 2 parts of Dyapol PHS and milled in a ball mill until the average particle size is reduced to 1-2 Fm.

20 parts of the resultant aqueous dispersion is diluted to 1000 parts with waterforform a dyebath. 100 parts of polyester yarn are introduced into the dyebath at room temperature and the temperature is then raised to 1 300C and maintained for one hour in a pressurised dyeing machine. After this time the yarn is removed, rinsed and dried. The polyester fibres are dyed bright red shades possessing good light, wet processing and sublimation fastness together with good build up properties.

Example 46 One part of the product from Example 44 is added to 18 parts of water and 2 parts of Dyapol PHS and milled in a ball mill until the average particle size of the dye is reduced to 1-2 Fm.

20 parts of the resultant aqueous dispersion is added to a mixture of 5 parts of a galactomannam thickening agent, such as that sold as "Indaica PA 3" and 5 parts of urea in 50 parts of water to form a paste which is then printed through a screen onto polyester fabric. After drying, the print is fixed by steaming for 20 minutes at 1.4 bar pressure. After this time the fabric is removed, washed and dried. The bright red print has good fastness to light and washing.

Example 47 Various mixtures of dyes of general formula II are prepared by coupling mixtures of diazotised amines of general formula III with coupling components of general formula IV, in the manner described in Example 44, the quantities of the various reactants being as described in the following table. All the resultant dyes gave bright red dyeings and prints on polyester when applied according to the methods described in Examples 45 and 46.

Example Mixed diazo components of formula Coupling component of No. III (where R4 & R5 = Br) general formula IV R' parts R' parts R2 R3 n parts 47:1 -CH2CH3 18.6 -CH(CH5)2 9.8 -CH3 -CH2CH3 2 23.1 47:2 -CH2CH3 20.9 -CH2CH2CH3 7.4 -CH3 -CH2CH3 2 23.1 47:3 -CH2CH3 16.5 -CH2CH(CH3)2 12.3 -CH3 -CH2CH3 2 23.1 47:4 -CH2CH3 14.0 -CH2CH2CH2CH3 15.4 -CH3 -CH2CH3 2 23.6 47:5 -CH3 8.8 -CH2CH3 18.6 -CH2CH3 -CH2CH3 2 24.6 47:6 -CH3 10.6 -CH(CH3)2 17.6 -CH2CH2CH3 -CH2CH3 2 26.0 47:7 -CH2CH3 18.6 -CH2CH2CH3 9.8 -CH2CH3 -CH2CH3 2 24.6 47:8 -CH2CH3 20.9 -CH(CH3)2 7.4 -CH(CH3)2 -CH2CH3 2 26.1 47:9 -CH2CH3 9.3 -CH(CH3)2 19.6 -CH3 -CH(CH3)2 2 24.7 47:10 -CH2CH3 11.16 -CH(CH3)2 15.8 -CH3 -CH2CH2CH3 2 24.6 47:11 -CH2CH3 11.9 -CH2CH2CH3 11.7 -CH3 -CH2CH(CH3)2 2 26.1 47::12 -CH2CH3 20.9 -CH2CH2CH2CH3 7.7 -CH3 -CH2CH3 3 24.5 47:13 -CH2CH3 16.7 -CH(CH3)2 11.7 -CH3 -CH2CH2CH3 3 26.0 47:14 -CH2CH3 14.0 -CH(CH3)2 14.7 -CH3 -CH(CH3)2 3 26.1 47:15 -CH3 8.8 -CH2CH3 18.4 -C2H5 -CH(CH3)2 3 26.5 47:16 -CH2CH2CH3 14.7 -CH(CH3)2 14.7 -CH3 -CH2CH3 2 23.1 47:17 -CH2CH3 23.5 -C(CH3)3 6.7 -CH3 -CH2CH3 2 23.1 Example 48 10.7 parts of 3-acetylamino-4-(2,6-dibromo-4-isopropylphenylazo)-N-2-cyanoethyl-N-ethylaniline and 10.4 parts of 3-acetylamino-4(2,6-dibromo-4-ethylphenylazo)-N-2-cyanoethyl-N-ethylaniline are added to 100 parts dimethylformamide and to this are added 4.7 parts of zinc cyanide and 0.4 parts of copper cyanide.

The mixture is warmed to 100 C and maintained at this temperature until thin layer chromatography shows the reaction to be complete. After cooling to room temperature the reaction mixture is added to water containing sodium perborate. After stirring for several hours the dye mixture of formula:

where R is a mixture of ethyl and iso-propyl, is filtered off, washed and dried.

Example 49 Other mixtures of dyes of general formula II are prepared from mixtures of compounds of general formula V in which R4 and R5 represent bromine atoms, by nucleophilic replacement of the said bromine atoms by cyano groups using the method described in Example 48.

These mixtures of compounds of general formula V are exemplified in the following table. Component 1 Component 2 Example R1 R2 R3 n parts R1 R2 R3 n parts No.

49:1 -CH2CH3 -CH3 -CH2CH3 2 19.9 -CH(CH3)2 -CH3 -CH2CH3 2 30.6 49:2 -CH2CH3 -CH3 -CH2CH3 2 21.1 -CH2CH2CH3 -CH3 -CH2CH3 2 29.0 49:3 -CH2CH3 -CH3 -CH2CH3 2 37.1 -CH2CH(CH3)2 -CH3 -CH2CH3 2 13.1 49:4 -CH2CH3 -CH3 -CH2CH3 2 35.3 -CH2CH2CH2CH3 -CH3 -CH2CH3 2 14.9 49:5 -CH2CH3 -CH3 -CH2CH3 2 39.6 -CH2CH2CH2CH2CH3 -CH3 -CH2CH3 2 10.7 49:6 -CH2CH3 -CH3 -CH2CH3 2 24.7 -CH2CH3 -CH3 -CH3CH2CH3 2 25.5 49:7 -CH2CH3 -CH3 -CH2CH3 2 19.8 -CH2CH3 -CH3 -CH(CH3)2 2 30.6 49:8 -CH2CH3 -CH3 -CH2CH3 2 29.7 -CH2CH3 -CH3 -CH2CH(CH3)2 2 21.0 49:9 -CH3 -CH2CH3 -CH2CH3 2 29.7 -CH3 -CH2CH3 -CH2CH2CH2 2 20.4 49:10 -CH3 -CH2CH3 -CH2CH3 2 24.7 -CH3 -CH2CH3 -CH(CH3)2 2 25.5 49:11 -CH3 -CH2CH3 -CH2CH3 2 28.3 -CH3 -CH2CH3 -CH2CH(CH3)2 2 22.5 49:12 -CH2CH3 -CH3 -CH2CH3 3 20.4 -CH(CH3)2 -CH3 -CH2CH3 3 31.4 49:13 -CH2CH3 -CH3 -CH2CH3 3 30.5 -CH2CH2CH2 -CH3 -CH2CH3 3 20.9 49: :14 -CH3 -CH2CH3 -CH2CH3 2 39.6 -CH3 -CH2CH2CH3 -CH2CH3 2 10.2 49:15 -CH3 -CH2CH3 -CH2CH3 2 19.8 -CH3 -CH2(CH3)2 -CH2CH3 2 30.6 49:16 -CH3 -CH2CH3 -CH2CH3 2 37.1 -C(CH3)3 -CH3 -CH2CH3 2 13.4 Example 50 15.3 parts of 2,6-dibromo-4-ethylaniline, 8.8 parts of 2,6-dibromo-4-isopropylaniline and 4.6 parts of 2,6-dibromo-4-secbutylaniline are diazotised and coupled to 23.1 parts of N-2-cyanoethyl-N-ethyl-3acetylaminoaniline according to the method described in Example 42. The resultant dye, when applied to polyester fibres according to the method described in Example 43, gives bright red dyeings of very good build up having good fastness to light, wet processing and sublimation.

Claims

1. Monoazo disperse dyes of general formula:

wherein R1 and R2 each independently represent an alkyl group such that the sum of their carbon atoms must total at least three, R3 is an alkyl group, and nis2or3.

2. Dyes as claimed in claims 1 wherein R1, R2 and R3 each contain 1 to 5 carbon atoms.

3. Dyes as claimed in claim 1 or 2 wherein R1 and R2 each contain 1 to 3 carbon atoms and R3 contains 2 to 5 carbon atoms.

4. Dyes of the formula given in claim 1 substantially as herein described with reference to and as illustrated in any of Examples 1,2 or 7 to 42.

5. A process for the preparation of dyes of the general formula given in claim 1 which comprises reacting a compound of general formula:

wherein R1,R2, R3 and n have the meanings given in claim 1 and R4 and R5 each represent a chlorine, bromine or iodine atom, with a metal cyanide whereby the groups R4 and R5 are replaced by cyanide groups.

6. A process as claimed in claim 5 wherein R4 and R5 are each bromine atoms.

7. A process for the preparation of dyes of the general formula given in claim 1 substantially as herein described with reference to and as illustrated in any of Examples 1,2 or 7 to 42.

8. A mixture of two or more of the dyes claimed in any of claims 1 to 4.

9. A mixture as claimed in claim 8 wherein the dyes differ in respect of the values of only one of the groups R1, R2 and R3.

10. A mixture as claimed in claim 8 or 9 wherein the dyes differ only in respect of the values of the group R1.

11. A mixture of two or more of the dyes as claimed in claim 1 substantially as herein described with reference to and as illustrated in any of Examples 5,44,47:1 to 47:17,48,49:1 to 49:16 or 50.

12. A process for the preparation of a mixture of two or more of the dyes claimed in claim 1 which comprises reacting a mixture of two or more intermediate compounds of general formula:

wherein R', R2, R3 and n have the meanings given in claim 1 and R4 and R5 each represent a chlorine, bromine or iodine atoms, with a metal cyanide whereby the groups R4 and R5 are replaced by cyanide groups.

13. A process for dying or printing hydrophobic fibres in which the dyeing is effected with a monoazo disperse dye of the general formula II as claimed in any of claims 1 to 4 or with a mixture of such dyes.

14. A process as claimed in claim 13 wherein the hydrophobic fibres are cellulose acetate fibres, polyamide fibres, polyacrylonitrile fibres or polyester fibres.

15. A process as claimed in claim 13 or 14 wherein the dye or mixture of dyes is dispersed by grinding with water and a dispersing agent.

16. A process as claimed in claim 13, 14 or 15 wherein polyester fibres are dyed from an aqueous bath at 95 to 1400C.

17. A process as claimed in claim 13, 14 or 15 wherein a dispersion of the dye or mixture of dyes is thickened with a thickener and applied to polyester fabric by padding or printing with a roller or through a screen, the fabric is dried and the dye is fixed.

18. A process for the dyeing or printing of hydrophobic fibres substantially as herein described in any of Examples 3,4,43,45 or 46.