Basic azo dyestuffs containing a n-picolinium alkylene amino phenyl group

Basic azo dyestuffs devoid of sulphonic acid and carboxylic acid groups and of the formula ##STR1## wherein A is an optionally substituted aromatic carboxylic or heterocyclic radical, R is an optionally substituted lower alkyl, aralkyl or cycloalkyl radical, Y is an optionally substituted alkylene radical of 1 to 4 carbon atoms, Z.sup..sym. is a 3- or 4-methylpyridinium group, X is an anion and the ring B may be further substituted, useful for dyeing synthetic polymeric materials especially polymers and copolymers of acrylonitrile.

This invention relates to basic azo dyestuffs containing pendant cationic 
groups, to the manufacture of such dyestuffs and to their use for the 
colouration of synthetic polymeric materials in the form of fibres, films, 
threads, tapes and textile materials generally and particularly for the 
colouration of polymers and copolymers of acrylonitrile and also acid 
modified polyesters and polyamides and polymers and copolymers of 
dicyanoethylene. 
According to the present invention there are provided basic azo dyestuffs 
devoid of sulphonic acid and carboxylic acid groups and of the formula: 
##STR2## 
wherein A is an optionally substituted aromatic carbocyclic or 
heterocyclic radical, R is an optionally substituted lower alkyl, 
cycloalkyl or aralkyl radical, Y is an optionally substituted alkylene 
radical of 1 to 4 carbon atoms, Z.sup..sym. is a 3- or 4-methylpyridinium 
group, X is an anion and the ring B may be further substituted. 
A, which is the residue of the diazo component, may be any aromatic 
carbocyclic or heterocyclic residue. A may for example be a radical of the 
benzene or naphthalene series and may carry as substituents any of the 
substituents normally found in dyestuff molecules, for example alkyl, 
cycloalkyl, aralkyl, alkoxy, aralkoxy, aryl, carbalkoxy, acyloxy, arylazo, 
acylamino, aryloxy, arylamino, carbamoyl, sulphamyl, alkylmercapto, 
arylmercapto, dialkylammino and substituted derivatives thereof and nitro, 
cyano, halogeno or trifluoromethyl groups. 
Examples of heterocyclic rings which may be represented by A include 
thiazole, isothiazole, benzthiazole, benzisothiazole, thiadiazole, 
triazole, quinoline, thiophene, pyrrole, indole, carbazole, pyridine, 
isoquinoline and quinoxalone rings, any of which may be substituted by the 
types of substituents listed hereinbefore. 
The ring B may be further substituted with any of the substituents normally 
present in dyestuff molecules, for example those types listed 
hereinbefore. 
R may be any optionally substituted lower alkyl, cycloalkyl or aralkyl 
radical. By the term lower alkyl we means alkyl containing from 1 to 4 
carbon atoms. Examples of R include methyl, ethyl, propyl, butyl, benzyl, 
cyclohexyl, isopropyl, cyclopentyl and isobutyl. 
Y may be any optionally substituted alkylene radical of 1 to 4 carbon 
atoms, examples of Y include 
##STR3## 
Y is preferably the --CH.sub.2 CH.sub.2 --radical. 
The group Z.sup..sym. is a 3- or 4-methylpyridinium group attached to the 
remainder of the molecule via the nitrogen atom and is preferably 
4-methylpyridinium. 
As anions represented by X.sup..crclbar. there may be mentioned for 
example inorganic anions such as chloride, bromide, iodide, nitrate, 
tetrachlorozincate, bisulphate or sulphate or organic anions such as 
acetate, propionate, methosulphate, methyl sulphonate, the water-soluble 
dyestuffs will contain a corresponding molar proportion of the cationic 
part of the dyestuff. 
Replacement of one anion by another anion in the dyestuff may be carried 
out by known methods, for example metathesis. 
A preferred class of dyestuffs of the present invention are dyestuffs of 
the formula: 
##STR4## 
wherein A and X are as hereinbefore defined, A.sup..sym. is 
4-methylpyridinium and wherein the ring B does not carry any further 
substituent or is substituted with a methyl group ortho to the azo group, 
X.sup..crclbar. is preferably chloride. 
A is preferably the residue of the diazo component derived from 
4-nitro-2-chloroaniline, 4-nitro-2-cyano-aniline, 
5-nitro-2-amino-thiazole, 3-phenyl-5-amino-1,2,4-thiadiazole or 
2,4-dinitro-6-bromoaniline. 
As a further feature of the present invention there is provided a process 
for the manufacture of the dyestuffs of the invention which comprises 
diazotising an amine of the formula A-NH.sub.2 and coupling the resultant 
diazonium salt in acid medium with a compound of the formula: 
##STR5## 
wherein A, B, R, Y, Z and X are as hereinbefore defined. 
Diazotisation and coupling may be carried out by methods known in the art. 
Examples of amines which may be used as diazo components include o-, m- or 
p-nitroaniline, 2,4-dinitroaniline, 2,4-dinitro-6-(chloro or 
bromo)-aniline, 4-methanesulphonylaniline, 4- or 5-nitro-2-toluidine, 4- 
or 5-nitro-2-anisidine, 2,4,6-trinitro- aniline, 
2,4-dinitro-6-carbomethoxyaniline, 2-amino-5-nitrobenzotrifluoride, 
2,4-bis(methanesulphonyl)aniline, 2-(chloro- or bromo-)-4-nitroaniline, 4- 
or 5-nitromethylanthranilate, 2,6-di(chloro- or 
bromo-)aniline-4-sulphonamide, 2,6-di(chloro- or 
bromo-)-4-methylsulphonylaniline, 2,5-di-(chloro- or 
bromo-)-4,6-dinitroaniline, 2-amino-3,5-dinitrobenzotrifluoride, 
3-amino-2-(chloro- or bromo-)-4,6-dinitro(toluene or anisole), 
3-amino-4-(chloro- or bromo-)-2,6-dinitro(toluene or anisole), 2- or 
4-cyanoaniline, 4-nitro-2-cyanoaniline, 2,4-dinitro-6-cyanoaniline, 
2-nitro-4-cyanoaniline, 2-chloro-4-cyanoaniline, 
3-amino-2,4,6-trinitrotoluene, 2-(chloro- or 
bromo-)-4-methylsulphonylaniline, 2-(chloro- or 
bromo-)-4-sulphamylaniline, 2-amino-5-nitrophenylmethylsulphone, 
2-amino-3,5-dinitrophenylmethylsulphone, 2-amino-3-(chloro- or 
bromo-)-5-nitrophenylmethysulphone, 2-sulphamyl-4-nitroaniline, 
2-methylsulphamyl- 4-nitroaniline, 2-ethylsulphamyl-4-nitroaniline, 
2-butylsulphamyl-4-nitroaniline, 2-dimethylsulphamyl-4-nitroaniline, 
2-methylsulphamyl-4,6-dinitroaniline, 2-methylsulphamyl-4-nitro-6-(chloro- 
or bromo-)aniline, 2-phenylsulphamyl-4-nitroaniline, 
methyl-2-amino-3-(chloro- or bromo-)-5-nitrobenzoate, 
dimethyl-2-amino-5-nitroterephthalate, 4-aminobenzenesulphonamide, 
2-nitro-4-methylaniline, 2-cyano-4-methylaniline, 4-aminobenzene-(2,5- or 
3,5-dichloro)benzenesulphon-N,N-dimethylamide, 
4-amino-3-chlorobenzenesulphon-N,N-dimethylamide, 
5-chloro-2,4-bis-(N,N-dimethylaminosulphonyl)aniline, 
2-chloro-5-cyanoaniline, 2-cyano-5-chloroaniline, 2,4-dicyanoaniline, 
4-aminodiphenylsulphone, 2-aminobenzenesulphon-N,N-dimethylamide, 2- or 
4-aminobenzonitrile, 2-aminophenylmethyl or ethylsulphone, 
3-amino-1,2,4-triazole, 2-amino-6-methoxybenzthiazole. . . . 
2-amino-6-nitrobenzthiazole 
5-amino-3-phenyl-1,2,4-thiadiazole 
2-amino-3,5-dicyano-4-methylthiophene 
2-amino-3-carbethoxy-5-nitrothiophene 
2-amino-3-cyano-5-nitrothiophene 
2-amino-3-nitro-5-cyanothiophene 
2-amino-3,5-dinitrothiophene 
2-amino-5-nitrothiazole 
2-amino-5-bromothiazole 
2-amino-5-chlorothiazole 
3-amino-5-nitro-2,1-benzisothiazole 
3-amino-5-nitro-7-bromo-2,1-benzisothiazole 
Examples of coupling components which may be used include 
N-2-(N-ethyl-N-phenylamino)-ethyl-4-methylpyridinium chloride 
N-2-(N-ethyl-N-3-methylphenylamino)-ethyl-4-methylpyridinium chloride 
N-2-(N-methyl-N-3-methylphenylamino)-ethyl-4-methylpyrid-inium chloride 
N-2-(N-ethyl-N-phenylamino)-ethyl-3-methylpyridinium chloride 
N-2-(N-ethyl-N-3-methylphenylamino)-ethyl-3-methyl pyridinium chloride 
N-2-(N-methyl-N-phenylamino)-ethyl-4-methylpyridinium chloride 
N-2-(N-propyl-N-phenylamino)-ethyl-4-methylpyridinium chloride 
N-2-(N-ethyl-N-3-chlorophenylamino)-ethyl-4-methylpyridinium chloride 
N-2-(N-ethyl-N-3-acetylaminophenylamino)-ethyl-4-methylpyridinium chloride 
N-3-(N-ethyl-N-phenylamino)-2-hydroxypropyl-4-methylpyridinium chloride 
N-2-(N-ethyl-N-2-methoxy-5-methylphenylamino)-ethyl-4-methyl pyridinium 
chloride 
Compounds of the formula: 
##STR6## 
required for the above process may be made by reacting a compound of the 
formula: 
##STR7## 
with for example phosphorus oxychloride, phosphorus trichloride, 
phosphorus pentachloride or preferably thionyl chloride either neat or in 
an inert solvent such as toluene at about 40.degree. to 75.degree. C. to 
convert the hydroxy group to chlorine and then reacting the product with 
4-methylpyridine to give the desired quaternary salt. 
In an alternative process the dyestuffs of the present invention can be 
manufactured by reacting 3- or 4-methylpyridine with a compound 
##STR8## 
wherein A, B, R and Y are as hereinbefore defined and R.sup.2 is a group 
capable of reacting with a tertiary base to give a cationic group. 
Compounds for use in this alternative process may be obtained for example 
by coupling a diazotised ANH.sub.2 on to a compound of the formula: 
##STR9## 
or by coupling on to a compound of the formula: 
##STR10## 
followed by replacement of the hydroxyl by halogen. 
Examples of R.sup.2 include sulphato groups and halogen atoms such as 
chlorine or bromine, particularly chlorine. 
This alternative process of the invention may conveniently be carried out 
by heating the compound and the 3- or 4-methylpyridine together in a 
solvent which may be an excess of the amine or solvents such as water, 
aryl halides such as monochlorobenzene and o-dichlorobenzene, 
tetrahydrofuran, acetone, N,N-dimethylformamide and dimethylsulphoxide or 
mixtures of these. Suitable reaction temperatures are from 20.degree. to 
150.degree. C. but higher temperatures may be used if desired. 
The dyestuff may be isolated from the reaction mixture for example by 
filtration if insoluble or by dilution with an appropriate non-solvent 
followed by isolation of the precipitated dyestuff or by dilution with 
water, separation of water-soluble impurities, and precipitation by 
salting out with, for example, sodium chloride or as a double salt, with 
zinc chloride. 
The dyestuffs of the present invention are advantageous over dyestuffs of 
similar structure but which have different cationic groups in that the 
present dyestuffs which have a 3- or 4-methylpyridinium cationic groups 
can be obtained in an improved physical form and have better solubility in 
water and aqueous organic solvents. The improved solubility is 
particularly good in the case of dyestuffs with a 4-methylpyridinium 
cationic group. It may be necessary in some cases to introduce a slight 
heat treatment at 35.degree. to 60.degree. C. into the isolation stage in 
order to obtain the improved physical form. 
Thus with some known dyestuffs such as Basic Red 18:1, precipitation from 
the coupling reaction gives a precipitate which is slow to filter and 
gives a filter paste or filter cake of only about 40% solids strength. 
Such a filter paste is slow to dry and additionally retains large 
quantities of salt which are deleterious to the aqueous solubility of the 
product particularly in concentrated liquid formulations. The related 
dyestuff of the present invention having a 4-methylpyridinium cationic 
group precipitates at 25.degree. C. in a better form than Basic Red 18:1 
and additionally it is found that on heating this precipitated product to 
35.degree. to 60.degree. C. a morphological change to a larger crystalline 
form takes place and the dyestuff filters rapidly to give a filter paste 
of approximately 75% solids. This has the advantage that it is easily 
dried minimising the previous bulk drying problem, the salt retention is 
much lower and aqueous solubility and solubility in aqueous organic liquid 
formulations is further increased. 
The dyestuffs of the invention are valuable for obtaining shades on 
synthetic polymeric materials in the form of textile materials by applying 
the dyestuff from an aqueous dyebath. The dyestuffs are particularly 
valuable for application to polymers and copolymers of acrylonitrile and 
of dicyanoethylene and polyesters, polyamides and cellulose esters and 
blends containing such materials. The polymeric materials may be modified, 
for example acid-modified. 
The dyestuffs of the invention may for example be applied to 
polyacrylonitrile or polydicyanoethylene materials from acid, neutral or 
slightly alkaline dyebaths (i.e. pH from 3 to 8) at temperatures between 
40.degree. and 120.degree. C. and preferably between 80.degree. and 
120.degree. C. or by printing techniques using thickened print pastes. 
On polyacrylonitrile, especially when the polyacrylonitrile has been 
modified to contain acidic groups, dyeings in bright yellow to blue shades 
are obtained which are distinguished by their good wet and light fastness 
and high tinctorial strength and build up. 
The dyestuffs of the invention may also be applied by a wet transfer 
printing process in which 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 and pressure under 
humid/wet conditions. 
The dyestuffs are also particularly valuable for colouration preferably 
from neutral dyebaths, of polyamide and polyester polymeric materials 
which are modified to contain acidic groups.

The invention is illustrated but not limited by the following Examples in 
which all parts and percentages are by weight unless otherwise specified. 
EXAMPLE 1 
Preparation of 4-nitro-2-chloroaniline 
N-2-(N'-ethylanilino)-ethyl-4-methylpyridinium chloride 
Diazotisation 
A slurry of 52.2 parts of 4-nitro-2-chloroaniline in 600 parts of water and 
70.2 parts of concentrated hydrochloric acid were stirred at ambient 
temperature for 18 hours. Crushed ice was then charged to reduce the 
temperature to 0.degree. C. and a solution of 21 parts of sodium nitrite 
in 60 parts of water added in one portion. The resulting diazo solution 
was stirred for 1/2 hour at 0.degree.-5.degree. C. in the presence of 
nitrous acid, filtered and excess of the latter removed by the addition of 
sulphamic acid solution. 
Coupling 
To the stirred diazo solution at 0.degree.-5.degree. C. was added, over 1/2 
hour, a solution of 91.25 parts of 
N-2-(N'-ethylanilino)ethyl-4-methylpyridinium chloride in 200 parts of 
water. 
After addition of the diazo solution was completed, the product began to 
precipitate as micro needles, c.a. 1.mu. in size. The reaction mixture was 
stirred for a further 3 hours at 0.degree.-5.degree. C. and then 18 hours 
at 20.degree. C. At this stage microscopic investigation showed the 
dyestuff to be present as crystalline, small needle-like clusters having 
an overall brownish appearance (the crystals which precipitated initially 
from the coupling medium had a reddish appearance). 
Morphological change 
20 Parts of sodium chloride (1% w/v) were charged to the reaction mixture 
and the temperature raised to 40.degree..sup..+-. 5.degree. C. and 
maintained at this level for a total of 5 hours. During this time, the 
dyestuff underwent a marked morphological change to much larger ruby-type 
crystals. The mixture was cooled at 30.degree. C. and filtered on a 15 cm 
nutsche in 25 secs. the highly crystalline product having a greenish 
sheen. 
It dyes Orlon a yellowish-red shade, rated trace blue and trace brighter v. 
Basic Red 18:1, having excellent fastness properties. 
It has superior aqueous solubility to Basic Red 18:1 as shown below, both 
dyestuffs having a chloride anion. 
______________________________________ 
Solubility in water 
Temperature (in grams/100 ml) 
.degree. C. Example 1 Basic Red 18.1 
______________________________________ 
30 2.5 2 
60 62 37 
90 &gt;100 39 
______________________________________ 
By a similar procedure, the following dyes may also be obtained: 
__________________________________________________________________________ 
Shade on 
Example 
Dyestuff Anion 
Polyacrylonitrile 
__________________________________________________________________________ 
##STR11## Cl.sup..crclbar. 
Rubine 
3 
##STR12## " Bordeaux 
4 
##STR13## " Orange 
5 
##STR14## Cl.sup..crclbar. 
Reddish-blue 
6 
##STR15## " Violet 
7 
##STR16## " Reddish-blue 
8 
##STR17## Cl.sup..crclbar. 
Orange 
9 
##STR18## " Reddish-yellow 
10 
##STR19## " Red 
11 
##STR20## Cl.sup..crclbar. 
Red 
12 
##STR21## " Violet 
13 
##STR22## " Red 
__________________________________________________________________________