GB2070050A - Cationic azo dyestuffs - Google Patents

Abstract

Novel cationic azo dyestuffs of the diazahemicyanine class for polyacrylonitrile are obtained by quaternising the compound formed by coupling diazo-thiazoles onto certain diphenylamines which may contain a further cationic group. Shades range from violet to greenish-blue, and they have the general formula <IMAGE> wherein R is optionally substituted lower alkyl, cycloalkyl, alkenyl or aralkyl, R<1> and R<2>, which are the same or different, are selected from hydrogen, optionally substituted alkyl, alkoxy, -COR<4>, halogen, arylamino, sulphonamido, sulphone thiomethoxy or aryl, R<4> is hydrogen or optionally substituted lower alkyl, lower alkoxy, amino, lower alkylamino or arylamino, R<2> is substituted allyl or -ZQ<+> or, when R% is -COR<4>, R<3> is hydrogen or optionally substituted lower alkyl, Z is optionally substituted allylene or arylene, Q<+> is a cationic group, A<{> is an anion, which is 1 or, when R<3> is -ZQ<+>, 2, and before rings A and B are optionally substituted.

Description

SPECIFICATION Cationic azo dyestuffs This invention relates to water soluble cationic azo dyes useful for the coloration of synthetic polymeric materials especially polymers and copolymers of acrylonitrile and dicyanoethylene and also acid modified polyester and polyamides.

According to the present invention there are provided water soluble azo dyestuffs devoid of carboxylic acid and sulphonic acid groups of formula (I)

wherein R is optionally substituted lower alkyl, cycloalkyl, alkenyl or aralkyl, R1 and R2, which are the same or different, are selected from hydrogen, optionally substituted alkyl, alkoxy,

halogen, arylamino, sulphonamido, sulphone, thiomethoxy or aryl, R4 is hydrogen or optionally substituted lower alkyl, lower alkoxy, amino, lower alkylamino or arylamino, R3 is substituted alkyl or --ZZ-Oo or, when R1 is

R3 is hydrogen or optionally substituted lower alkyl, Z is optionally substituted alkylene or arylene, Qs is a cationic group, As is an anion, n is an integer which is 1 or, when R3 isZQQ3, 2, and benzene rings A and B are optionally substituted.

The term "lower" when applied herein to an alkyl or alkyl-containing group refers to such a group in which the alkyl moiety contains from 1 to 4 carbon atoms.

The cationic group Qs may be any such group commonly used in cationic dye technology.

Examples of such a group are protonated amino, quaternary ammonium, cyclammonium, hydrazinium, sulphonium, isothiouronium, etherified hydroxylammonium and phosphonium groups. There are more fully described in, for example, UK Patent Specification No. 1482234.

The anion A3 may be any organic- or inorganic-based anion known to be used with cationic dyes such as those described in the Patent Specification mentioned in the last paragraph. In particular we would mention chloride, methyl sulphate, acetate, bisulphate and tetrachlorozincate. Where Ao is polyvalent the dyestuff will contain a corresponding molar proportion of the cationic moiety.

The benzene rings A and B may each be substituted with one or more of the substituents normally to be found in dyestuff molecules, for example, lower alkyl and lower alkoxy. In particular we would mention methyl, methoxy and ethoxy. Substituents may together form a group linking the benz rings A and B. Such a linking group may be an alkylene or alkylidene group, especially isopropylidene.

In a preferred aspect of our invention we provide dyestuffs of formula (il)

wherein R5 is optionally substituted lower alkyl or lower alkoxy, R6 is hydrogen or optionally substituted lower alkyl, R7 and R8, which are the same or different, are hydrogen, lower alkyl or lower alkoxy and As has the meaning hereinbefore defined.

It is further preferred that R5 is optionally substituted lower alkoxy because we have found that an ester group in the 5-position of the thiazole ring confers better light fastness than an acvl aroun.

In particular we would mention the dyestuffs of formula (II) in which R5 is ethoxy, R6is hydrogen, methyl or hydroxyethyl, R7 is hydrogen, methyl, methoxy or ethoxy, R8 is hydrogen or methoxy and Ao is chloride or tetrachlorozincate.

The dyes of formula (II) are tinctorially strong mid-blue dyes which are brighter than Basic,Blue 41.

They exhibit good all round properties and excellent light fastness. Compatibility values (CV) are generally in the desired range of 2.5 to 3.5. Corresponding dyes derived from N,N-dialkyl anilines have higher compatibility values closer to 5. The relevance of compatibility values to cationic dyes is discussed later.

In another preferred aspect of our invention we provide dyestuffs of formula (ill)

wherein R9 is hydrogen or lower alkyl, R10 is hydrogen or

R13 is optionally substituted lower alkyl or alkoxy, Z is lower alkylene optionally containing a hydroxy substituent, Q is cyclammonium, especially pyridinium, 2- or 4-picolinium or 4-N,N-dialkylamino pyridinium. and R7, R8 and As have the meanings hereinbefore defined.

In particular we would mention the dyestuffs of formula (III) in which R7 is hydrogen, methyl, methoxy or ethoxy, R8 is hydrogen or methoxy, R9 is hydrogen or methyl, R is hydrogen, ethoxy, carbonyl or methyl carbonyl, Z is ethylene orp-hydroxypropylene, Q is pyridinium, 4-methyl pyridinium or 4-N,N-dimethylaminopyridinium and A# is chloride or tetrachlorozincate.

The dyes of formula (III) are violet to blue dyes of high tinctorial strength, good aqueous solubility, good light fastness and good general properties.

In yet another preferred aspect of our invention we provide dyestuffs of formula (IV)

wherein R1' is branched or unbranched alkyl containing from 1 to 6 carbon atoms and carrying one or more substituents selected from hydroxyl, cyano, chloro, bromo, and groups containing

or -0-, and R7, R8, R9, R10, A# have the meanings hereinbefore defined.

More particularly R11 is R12-X wherein R12 is a branched or unbranched alkylene chain containing from 1 to 6 carbon atoms and optionally carrying a hydroxyl substituent, X is cyano, bromo, chloro, hydroxyl,

and R'3 is lower alkyl.

Especially we would mention the dyes of formula (lV) in which R7 is hydrogen, methyl, methoxy or ethoxy. R8 is hydrogen, methyl or methoxy, R9 is hydrogen or methyl, R10 is hydrogen, ethoxycarbonyl or methyl carbonyl, R" is /3-cyanoethyl, y-chloro-P-hydroxypropyl, /3,y-dihydroxy propyl, i3- ethoxycarbonylethyl, or ,B-hydroxyethyl and Ao is chloride or tetrachlorozincate.

The dyes of formula (IV) are violet to greenish blue dyes of high tinctorial strength, good light fastness and good general properties.

In a further aspect of the present invention there is provided a process for the manufacture of the dyestuff of the present invention which comprises quaternising a compound of the formula (V)

wherein R', R2, R3 and the benzene rings A and B are as hereinbefore defined.

As examples of quaternising agents there may be mentioned alkyl halides such as methyl, ethyl, propyl and butyl chlorides and the corresponding bromides, alkenyl halides such as alkyl chloride or bromide, aralkyl halides such as benzyl chloride or bromide, dialkyl sulphates such as dimethyl sulphate, diethyl sulphate, dipropyl sulphate and dibutyl sulphate, alkyl esters of aryl sulphonates such as methyl and ethyl p-toluene sulphonate and other lower alkyl esters of strong mineral acids or organic sulphonates. Other quaternising agents may themselves carry substituents, for example chloropropionitrile, bromopropionamide and bromohydrin.

The reaction between the quaternising agent and dyestuff of formula (V) may be carried out neat without addition of other solvents, or again may be carried out in an inert organic solvent such as benzene, toluene, xylene, chlorobenzene, nitrobenzene, acetone, carbontetrachloride, tetrachloroethane, perchloroethylene, chloroform, dimethylformamide, acetonitrile, acetic acid, formic acid or 2ethoxyethanol. The quaternisation may also be effected in aqueous phase optionally in the presence of an organic solvent. The quaternising agent may be used in considerable excess, for example up to 6 moles for each mole of dyestuff. Suitable temperatures are from 200 to 1 500C and particularly 20--900C. The inclusion of an acid-binding agent is often beneficial.Such agents include magnesium oxide, sodium and potassium carbonate, sodium and potassium bicarbonate, magnesium and calcium carbonate, potassium acetate or mixtures of such agents.

Quaternisation of dyestuffs of formula (V) may also be carried out by reacting with, for example, acrylamide in an organic or mineral acid such as acetic, formic or hydrochloric acid or mixtures of these at between SOC and 1000C.

Quaternisation may also be carried out by reacting a dyestuff of formula (V) with ethylene oxide or its derivatives of formula:

wherein R14 and R'5 represent hydrogen or an optionally-substituted lower alkyl group.

This reaction is carried out in a solvent in the presence of a mineral or organic acid which provides the anion Ao, at temperatures of 100 to 1 000C and preferably 40-900C. Suitable acids include sulphuric, hydrochloric, hydrobromic, phosphoric, benzenesulphonic, toluenesulphonic, formic, acetic or propionic. Such acids may also serve as solvent or may be used in admixture with each other or with other organic solvents such as dimethylformamide, acetonitrile, dioxan, tetrahydrofuran, chlorobenzene, toluene, xylene, nitrobenzene, acetone or methylethylketone.

When the reaction is effected in hydrophobic organic solvents the quaternised dyestuff is normally insoluble and may be isolated by filtration. If desired, the quaternised dyestuff may be isolated from aqueous solution by precipitation in the form of a salt such as tetrachlorozincate obtained by adding zinc chloride to the aqueous solution.

As a result of the quaternisation the dyestuff may be obtained, for example, in the form of the chloride, bromide or methosulphate according to the quaternising agent used. If the dyestuff is required as the salt of a different anion, then one anion may be replaced by another by known methods of metathesis.

Compounds of formula (V) which can be used as starting materials in the above process can be made by diazotising the appropriate 2-aminothiazole and coupling the diazo component so obtained with a coupling component of the formula (VI)

wherein R3 and benzene rings A and B are as hereinbefore defined.

In an alternative process which is a further feature of this invention the dyestuffs of formula (III) may be made by (a) reacting a compound of formula (VII)

wherein Z and benzene rings A and B are as hereinbefore defined, X is a direct link or a linking group and Y is halogen, sulphato or a sulphato ester group, with a tertiary amine, such as pyridine or trimethylamine, followed by reaction with a quaternising agent as in the process previously described; or (b) reacting a compound of formula (V) as above defined with a secondary amine and then reacting the product with two or more moles of a quaternising agent.

The dyestuffs of the present invention may be used to colour polymeric materials by application from an aqueous bath.

In particular the dyestuffs of the invention are valuable for dyeing polyacrylonitrile materials and may be applied to polyacrylonitrile materials from acid, neutral or slightly alkaline dyebaths, (i.e. pH from 3-8) at temperatures between 40-1 200C and preferably between 80-1200C or by printing techniques using thickened print pastes. Tinctorially strong violet to greenish-blue dyeings of good to excellent light fastness and good all round properties are obtained.

The dyestuffs of the present invention may be used for the colouration of polymeric textile materials, particularly polymers and copolymers of acrylonitrile, by the wet transfer printing process. In this process a support, such as paper, is printed with an ink containing a dyestuff, the printed support is placed in contact with a textile material and the whole then subjected to heat pressure under humid or wet conditions and the dyestuff transferred to the textile material.

The dyestuffs of the present invention generally exhibit good Compatibility Values especially those of formula (II) which have values in the range of 2.5 to 3.5.

Compatibility Values can be assessed by the method described in the Journal of the Society of Dyers and Colourists, Volume 87, No.2, page 60 (1971). They are assessed on a scale of 1 to 5 and dyers engaged in the dyeing of polyacrylonitrile materials show a strong preference for dyestuffs having a Compatibility Value (C.V.) of 2.5 to 3.5. Dyestuffs of this C.V. are compatible in dyeing properties with the large majority of mainstream commercial dyes used in the dyeing of polyacrylonitrile and the dyeing rates of mixtures of dyestuffs with C.V. about 3 is such that the dyeing can be more easily controlled and the shade determined and adjusted during dyeing if this should be necessary.

The invention is illustrated but not limited by the following Examples in which all parts and percentages are by weight unless otherwise stated. Where parts by volume are given, the relation of weight to volume is the relation of gram to millilitre.

EXAMPLE 1 3.7 parts of 2-amino-4-methyl-5-ethoxycarbonyl thiazole (prepared by reaction of thiourea with ethylchloro acetoacetate in water) is dissolved in a mixture of 20 parts by volume of glacial acetic acid and 20 parts by volume of propionic acid at O to 50C. To the stirred solution is added 10 parts by volume of nitrosyl sulphuric acid and stirring is continued at O to SOC for a further hour to complete the diazotisation.

4 parts of N-methyldiphenylamine is dissolved in 50 parts by volume of acetone at O to 50C with stirring. After addition of the diazo solution, the resulting blue coupling solution is stirred for 12 hours, then diluted with 100 parts by volume of water and neutralised by the addition of concentrated ammonia liquor (S.G. 1.88) at 0--50C.

The precipitated product is filtered off and washed copiously with cold water. Examination of the product by Thin Layer Chromatography (TLC) indicates a single rubine coloured spot.

1.2 parts of the dye base is dissolved in 30 parts by volume of chlorobenzene at 800C and 5 ml of dimethyl sulphate is added. After stirring for an hour at 800 C, the reaction is essentiaily complete (as judged by TLC). After allowing the solution to cool slowly over 1 8 hours, the crystallised blue dyestuff is filtered off.

The product is dissolved in warm water, filtered through Hyflo Supercel filter and precipitated from the filtrate by the addition of sodium chloride. It is filtered off and dried at 400C.

It dyes ORLON (RTM) polyacrylonitrile material a mid-blue shade, similar to Basic Blue 41, but a little brighter. The dye is compatible with the majority of commercial cationic dyes, having a Compatibility Value (CV) of 2.5. The dyed cloth has good fastness properties, including excellent fastness to light.

EXAMPLES 2-14 Dyes having the formula (II)

in which R5, R6, R7, R8 and A- have the meanings given in Table I are obtained by a method similar to that described in Example 1.

TABLE I

Shade on poly acrylonitri le Example R5 R6 R7 R" Anion (PAN) 2 OC2H5 CH2 CH2 H Cl- Mid-blue 3 " " OCH3 " " Greenish-blue 4 " " OC2H5 " " " 5 " " CH3 OCH3 ZnCl42# " 6 " H " " " Blue 7 " " H " Cl- " 8 " CH3 " " " " 9 ,, H OC2Hs H ZnCl42 # Greenish-blue 10 " " H " " Mid-blue 11 CH3 CH3 " " " " 12 " H " " " " 13 ,, CH3 CH3 OCH3 " Blue 14 OC2H5 C2H4OH H H " Mid-blue EXAMPLE 15 The turquoise dyestuff of formula (V)

is also obtained by a method similar to that described in Example 1.

EXAMPLE 16 Preparation of N-ss-chloroethyldiphenylamine 15.3 parts of phosphorus oxychloride is stirred at 700C and 21.3 parts of N-ss- hydroxydiphenylamine is added gradually, the temperature rising to 100 C. After stirring for a further + hour at 1000C, analysis by TLC indicates complete reaction. (A sample coupled with diazo p-nitroaniline gave only a single yellowish-red spot of higher Rf value than the starting material using as eluent chlorobenzene:acetone:acetic acid 85:10:5 on a silical gel plate).

The oily product is cooled to 250C and poured into 200 parts of cold water with stirring and the resulting oil extracted with ether. "Hyflo Supercel" (RTM) filter aid and Carbon DY3 is added to the ether extract which is then filtered and the filtrate dried over anhydrous magnesium sulphate. Removal of the solvent leaves a clear oily product.

6.5 parts of N-p-chloroethyidiphenylamine is dissolved in 30 parts by volume of pyridine and the solution boiled under reflux for 1 8 hours. Analysis by TLC indicates quaternisation to be complete (one yellowish-red spot of lower Rf value than starting material -- after coupling both with diazo pnitroaniline and eluting with chloroform:methanol:acetic acid 1 5:5:1 on a silica gel plate).

The yellow solution is poured into 200 parts by volume of ethyl acetate and, with stirring, the resulting yellow oil solidified. The pale yellow solid is filtered off, triturated with ethyl acetate, refiltered and finally dried at 700C.

Preparation ofMonocationic Dye 1.5 parts of 2-aminothiazole is dissolved in a mixture of 20 parts by volume of glacial acetic acid and 20 parts by volume of propionic acid, the stirred solution cooled to 0 to SOC, and 7.5 parts by volume of nitrosyl sulphuric acid added dropwise. After stirring for 2 hours at 0 to 50C, the diazotisation is complete.

The diazo solution is added dropwise to a stirred solution of 2.5 parts of 2-(NN-diphenylamino)ethyl pyridinium chloride in 50 parts by volume of methanol at 0 to 50C. After stirring for an hour at 0 to 5 C, the blue coupling solution is poured into 200 parts of water and neutralised by the addition of concentrated ammonia liquor (S.G. 0.88), an orange solution being obtained. Addition of sodium chloride and zinc chloride precipitates the dye, which is filtered off and dried.

Preparation ofBis-cationic Dye The monocationic dye is dissolved in 25 parts by volume of glacial acetic acid and 0.5 parts of light magnesium oxide and 5 parts by volume of dimethyl sulphate are added. The mixture is stirred and heated to 600C and maintained at this temperature for 2 hour to complete the reaction.

After pouring the violet solution into 200 parts of water, the product is isolated as a tarry precipitate by the addition of sodium chloride and 100% aqueous zinc chloride solution. This is dissolved in hot water and re-precipitated by the addition of sodium chloride. The dyestuff is filtered off, the cake slurried in a small volume of cold water to remove the majority of inorganic material and filtered off. The violet coloured solid is dried at 4000.

It dyes ORLON (RTM) polyacrylonitrile material a violet shade, the dyed cloth having good fastness.

properties.

EXAMPLES 17-23 Dyes having the formula shown in Table II are obtained by a method similar to that described in Example 16.

TABLE II

sXample Dye Anion PAN on 17 CR jzncl ddish 1? CH iZnCl4243 Reddish CR/\ blue O > blue 3 C2H50 C2HjbN+ 5 S 18 C3 CR3 OCEl3 1e ,t NCQ-.

2 =tCH3 19 CR3CR I' Blue o C CR o 20 | CR CH CR3 jZnC1426 > ReddiE!X e 3 < 4 CH3 blue CHO""'0 ( 2 5 S 0CR3 c2geN(Ca3) I OCH 1 ai CH3 n > Cl Cl-Blue OCE' ~ '.

CR 3 CH 22 6 / 3 MA ZnC14 9 Blue 0 > N c- ss=N3 C2H50 \ S CH2CECHU OH 23 CR / G2] 5Cl9 n OC H CH2HCII.?N\' C2H50 S CH27HCH2N=t CH, OH EXAMPLE 24 5 parts of 2-aminothiazole are dissolved in a mixture of 50 parts by volume of glacial acetic acid and 50 parts by volume of propionic acid. The solution is filtered and cooled to O to 5 C and diazotised by the dropwise addition of 25 parts by volume of nitrosyl sulphuric acid; a further 2 hours stirring at O to SOC is needed to complete the reaction.

10.7 parts of N-P-hydroxyethyldiphenylamine is dissolved in 50 parts by volume of acetone and the solution added dropwise to the stirred diazo solution at O to 5 C. After a further 2 hours, the coupling mixture is poured onto 200 parts of ice and the excess liquid decanted off, leaving a tarry solid product.

3 parts of the tarry solid is dissolved in 75 parts by volume of glacial acetic acid. 0.5 parts of light magnesium oxide and 5 parts by volume of dimethyl sulphate is added and the mixture heated to 600C and maintained at this temperature for 3 hours with stirring to complete the quaternisation.

After cooling to 250C, the blue solution is drowned into 200 parts of water, the resulting solution filtered to remove traces of insoluble material, and 100% aqueous zinc chloride solution added to the filtrate to precipitate the dye. This is filtered off and dried.

It dyes ORLON (RTM) polyacrylonitrile material a bright reddish-blue shade; the dyed cloth has good wet fastness and good light fastness.

EXAMPLES 25-33 Dyes having the formula (IV)

in which R7, R8, R9, R10, R11 and AO have the meanings given in Table Ill are obtained by methods similar to that described in Example 24.

TABLE Ill

Ex. R7 RB R9 RIO Rtl Anion Shade on PAN 20 Bluish-violet 25 H H H H C2H4CN %ZnC142E) Bluish-violet OH 26 .. ,, ,, .. CH2CHCH2CI 55 Reddish-blue OH 27 i ,, .. . CH2CH2CH2OH .. IS 28 .. .. ,, .. O2H4O0OO2H5 Cl(3 29 .. ,, CH3 COOC2Hs C2H40H ZnOl42 Blue 30 OC2H5 " " " I, Ol0 Mid-blue 31 - OCH3 CH3 ,, .. ,r S, aS 32 CH3 OCH3 ,, .. .. %ZnC 142 1ZnCI, 20 Reddish-blue 33 H H .. COCH3 ,, .. Blue

Claims (6)

1. Water soluble azo dyestuffs devoid of carboxylic acid and sulphonic acid groups of formula (I)

wherein R is optionally substituted lower alkyl, cycloalkyl, alkenyl or aralkyl, R1 and R2, which are the same or different, are selected from hydrogen, optionally substituted alkyl, alkoxy,

halogen, arylamino, sulphonamido, sulphone, thiomethoxy or aryl, R4 is hydrogen or optionally substituted lower alkyl, lower alkoxy, amino, lower alkylamino or arylamino, R3 is substituted alkyl or -Z-Q# or, when R' is

R3 is hydrogen or optionally substituted lower alkyl, Z is optionally substituted alkylene or arylene, Q# is a cationic group, As is an anion, n is an integer which is 1 or, when R3 is ZQe, 2, and benzene rings A and B are optionally substituted.

2. Dyestuffs according to claim 1 of formula (II)

wherein R5 is optionally substituted lower alkyl or lower alkoxy, R6 is hydrogen or optionally substituted lower alkyl, R7 and R8, which are the same or different, are hydrogen, lower alkyl or lower alkoxy and As is an anion.

3. Dyestuffs according to claim 1 of-formula (III)

wherein R9 is hydrogen or lower alkyl, R10 is hydrogen or

P13 is optionally substituted lower alkyl or alkoxy, Z is lower alkylene optionally containing a hydroxy substituent, Q is cyclammonium, especially pyridinium, 2- or 4-picolinium or 4-N,N-dialkylamino pyridinium, and R7, R8 and AO have the meanings defined in claim 2.

4. Dyestuffs according to claim 1 of formula (IV)

wherein P11 is branched or unbranched alkyl containing from 1 to 6 carbon atoms and carrying one or more substituents selected from hydroxyl, cyano, chloro, bromo, and groups containing

or -0-, and R7, P8 R9, R10, AO have the meanings defined in claim 3.

5. A process for the manufacture of the dyestuffs according to claim 1 which comprises quaternising a compound of the formula (V)

wherein R1, R2, R3 and the benzene rings A and B are as defined in claim 1.

6. A process for the manufacture of the dyestuffs according to claim 3 which comprises (a) reacting a compound of formula (Vli)

wherein Z and benzene rings A and B are as hereinbefore defined, X is a direct link or a linking group and Y is halogen, sulphato or a sulphato ester group, with a tertiary amine, followed by reaction with a quaternising agent; or (b) reacting a compound of formula (V) as defined in claim 5 with a secondary amine and then reacting the product with two or more moles of a quaternising agent.