DE1234891B - Process for the production of azo dyes - Google Patents

Description

Process for the preparation of azo dyes It has been found that valuable new azo dyes are obtained if sulfonic acid group-free azo dyes of the general formula are used Reacts with alkylating agents. The products obtainable in this way can, after alkaline treatment, be subjected a second time to the action of alkylating agents, further alkylation of the dyes taking place.

In the general formula, A stands for the radical of a five- or six-membered hetero ring which, in addition to the nitrogen atom, can also contain other heteroatoms, such as S or further N atoms, and which can have customary substituents, such as alkyl, cycloalkyl, aryl , Carboxylic acid ester, - NH2, - NH-acyl, acyl and alkoxy groups or halogen substituents; the ring A can also carry fused aromatic rings which in turn can have the aforementioned or other substituents, R denotes H or an optionally substituted alkyl or aryl radical; R2 stands for H or an optionally further substituted alkyl radical; R3 denotes H or a substituent, for example halogen or an alkyl, CF3, NH2, NH-acyl, -NR-acyl, an optionally further substituted sulfonamide or carbonamide radical, a carboxylic ester or nitro group; X represents either a direct bond or the group n stands for the number 1, 2 or 3.

The new dyes obtainable in the first stage according to the process correspond to the probable formula Here A, X, Ri, R2, R3 and n have the meaning given above; R4 represents an alkyl, cycloalkyl or aralkyl radical, and Y- represents an anion.

If the radical R2 in formula II is hydrogen, the alkylated dyes can be converted into the associated free bases by treatment of their aqueous solutions or suspensions with alkalis, which in turn can be alkylated again, with cationic dyes of the probable formula in which A, X, Ri, R3, R4, Y- and n have the abovementioned meaning and R, denotes an alkyl, cycloalkyl or aralkyl radical.

The azo dyes of the formula I to be used as starting compounds can be prepared, for example, by adding heterocyclic compounds which carry a diazotizable amino group and of the formula correspond, in which A has the meaning given above, diazotized in the usual way and the diazo compounds with pyrazolo [1,5-a] benzimidazoles or pyrazolo [5,1-b] quinazolones of the formula wherein X, Ri, R2, R3 and n have the meaning given above, couples. The pyrazolo [1,5-a] benzimidazoles and pyrazolo [5,1-b] quinazolones used here as azo components can be prepared by the processes of German patent 1,120,455 and Austrian patent 216,505.

According to the invention, the term alkylation also includes the introduction understood by aralkyl and cycloalkyl radicals. Preferred alkylating agents are Alkyl, aralkyl or cycloalkyl halides, such as methyl chloride, ethyl bromide, benzyl chloride, Phenacyl chloride, also dialkyl sulfates or alkyl esters of aromatic sulfonic acids, such as dimethyl sulfate, ethyl p-toluenesulfonate and others.

The alkylation is expediently carried out in organic solvents, such as carbon tetrachloride, benzene, dichlorobenzene or nitrobenzene, with increased Temperature executed. Simultaneously with the quaternization of the Dye (formation of the cationic dye) can be used as substituents in the molecule any amino, hydroxyl or carboxyl groups present or still present in hetero rings hydrogen-bearing N atoms are alkylated, etherified or esterified.

Both the single (Formula 1I) and the double (Formula III) alkylated process products have the character of basic dyes and are more or less soluble in water. Some of the mono-alkylated dyes are Very sparingly soluble in water, but become very good as a result of the second alkylation water soluble.

If the water solubility is sufficient, the dyes can be used for Dyeing or printing of synthetic materials such as fibers, flakes, threads, Tapes, foils and the like made of polyacrylonitrile and predominantly containing acrylonitrile Use mixed polymers to achieve pure and true colors. Even Stained cotton can be dyed in clear, genuine tones. The heavily in water to insoluble process products can either be used in aqueous dispersion for dyeing of synthetic materials, e.g. B. from polyacrylonitrile, use or by reaction with suitable acids or acidic dyes in lacquer or pigment dyes being transformed.

The parts mentioned in the following examples are parts by weight.

Example 1 To prepare the starting dye, diazotization is carried out in Usually 30 parts of 2-aminobenzothiazole and combined the diazo solution with one aqueous, hydrochloric acid solution of 34.5 parts of 2-methylpyrazolo- [1,5-a] benzimidazole. The coupling to the azo dye starts immediately and ends after a short time. The reaction mixture is blunted for complete precipitation of the azo dye formed to about pH = 4, filtered and washed the dye repeatedly with water. To drying gives 62 parts of brown powder.

33.2 parts of the starting azo dye thus obtained are in 300 parts Stirred chlorobenzene, heated to 100 ° C and slowly with 13 at this temperature Parts of dimethyl sulfate are added. This is followed by a further 2 hours at 110 to 120 ° C touched. After cooling, the dye formed is filtered off with benzene washed and dried. 43 parts of a dark brown powder are obtained. The dye is very sparingly soluble in water. It dyes polyacrylonitrile fibers from an aqueous dispersion yellowish red.

Example 2 The 43 parts obtained according to Example 1 are monoalkylated Dye are mixed in 1000 parts of water, with soda to a pH of 8 to 9 set and stirred at 15 to 20 ° C for 1 hour. After suction and Drying gives 32 parts of a red-brown powder.

17.3 parts of this powder are mixed in 200 parts of o-dichlorobenzene and heated to 100 ° C. At this temperature, 6.3 parts of dimethyl sulfate gradually become added and then stirred at 120 to 130 ° C for 2 hours. The bisalkylated one After cooling, the dye is filtered off, washed with benzene and dried. 22 parts of a dark red-brown powder are obtained, which dissolves in water with red Color dissolves. The dye colors structures made of polyacrylonitrile from weak to strong acid bath in very real red tones. Example 3 37.6 parts of the diazotized 6-ethoxy-2-aminobenzothiazole and 2-methylpyrazolo [1,5-a] benzimidazole Azo dye are mixed in 350 parts of o-dichlorobenzene and gradually increased at 100.degree mixed with 12.6 parts of dimethyl sulfate. This is followed by a further 2 hours at 120.degree touched. After cooling, filtering, washing with benzene and drying, one obtains 48 parts of a red-brown powder which is very sparingly soluble in water, the polyacrylonitrile fibers dyes from aqueous dispersion in bluish-tinted red shades.

Example 4 48 parts of the monoalkylated obtained according to Example 3 Dye are mixed in 1000 parts of water and stirred at pH 8 to 9 for 1 hour. After suctioning off, it is washed with water and dried. 35 parts are obtained a brown one Powder. 19.5 parts of this powder are divided into 250 parts Stirred chloroform and treated with 6.3 parts of dimethyl sulfate. Then 4 hours heated to boiling. After cooling, the bisalkylated dye is filtered off and dried. 24 parts of a water soluble in blue-red color are obtained Powder that is made from an acid bath structure made of polyacrylonitrile or containing acrylonitrile Copolymers dyes in intense bordo shades of very good fastness properties. example 5 26.6 parts of that obtained from diazotized 3-amino-triazole- (1,2,4) and 2-methylpyrazolo [1,5-a] benzimidazole available azo dye are mixed in 250 parts of chlorobenzene and heated to 100.degree gradually mixed with 12.6 parts of dimethyl sulfate. Then stir 2 hours at 110 ° C, allowed to cool and isolate the alkylated dye through Filter off. 37 parts of a readily water-soluble yellow powder are obtained. The dye colors structures made of polyacrylonitrile or acrylonitrile-containing structures from an acid bath Copolymers in very real yellow tones. Example 6 Those obtained according to Example 5 37 parts of alkylated dye are dissolved in 500 parts of water and made up with soda pH = 8 to 9 set. It is stirred for one hour at room temperature and the now water-insoluble free dye base was filtered off and dried. There will be 20 parts obtain. 14 parts of this dye are mixed in 100 parts of nitrobenzene and at 100'C with 7.7 parts of diethyl sulfate. After stirring for 2 hours at 110'-C is cooled and the bisalkylated dye formed is filtered off. Man contains 18 parts of a very readily water-soluble yellow powder. The dye colors structures made of polyacrylonitrile from an acidic bath in a very real reddish-tinged yellow Tones.

Dyes with coloring properties very similar to those of Examples 5 and 6 are obtained when using the diazotized 3-amino-1,2,4-triazole-carboxylic acid (5) and 2-methylpyrazolo- [1,5-a] benzimidazole available dye for mono- or. Bisalkylation analogous to the procedure described in Examples 5 and 6. Example 7 17.5 Parts of the diazotized 2-aminothiazole and 2 - methyl - 7 - trifluoromethyl - Pyrazolo [1,5-a] -benzimidazole prepared monoazo dye are in 250 parts Chlorobenzene was stirred and 6.3 parts of dimethyl sulfate were added at 100 ° C. Then The mixture is stirred at 110 to 120 ° C. for a further 2 hours. After cooling, the monoalkylated Dye filtered off and dried. 22 parts of a sparingly water-soluble one are obtained Powder, the polyacrylonitrile fibers from dispersion in real, yellowish-red tones colors.

Example 8 22 parts of the monoalkylation product obtained according to Example 7 are stirred in 400 parts of water, with soda or sodium hydroxide solution to a pH value from 8 to 9 and stirred for 1 hour at room temperature. Then the dye vacuumed, washed and dried. 15 parts of a brown-red powder are obtained. 9.1 parts of this powder in 150 parts of chlorobenzene at 100 ° C with 3.2 parts Dimethyl sulfate reacted and after the addition of the dimethyl sulfate a further 2 hours. at 110 ° C stirred. After cooling, the bisalkylated dye is filtered off with suction, with Benzene washed and dried. 11 parts of a red-brown are obtained, with a red one Color of water-soluble powder made from acidic bath polyacrylonitrile fibers yellow-tinged red dyes with good fastness properties.

Example 9 20.4 parts of that obtained from diazotized 5-methyl-2-aminobenzothiazole and 2-phenylpyrazolo [1,5-a] benzimidazole are obtained in 300 parts Trichlorobenzene at 100-'C with 7.7 parts of diethyl sulfate and 2 hours at Stirred at 120 ° C. It is then cooled, the dye formed is filtered off and dried. 25 parts of the monoalkylated dye are obtained as a dark brown-red powder, that is sparingly soluble in water. The dye colors polyacrylonitrile from aqueous Dispersion in real red tones.

Example 10 25 parts of the dye obtained according to Example 9 are used stirred in 500 parts of water for 1 hour at pH = 8 to 9. After filtering off the dye washed with water and dried. 10.6 parts of the thus obtained Product are in 200 parts of o-dichlorobenzene at 100 C with 3.2 parts of dimethyl sulfate added and stirred at 120.degree. C. for 2 hours. After cooling, vacuuming and drying 12 parts of a dark brown, soluble in water with a blue-red color are obtained Powder, the polyacrylonitrile from an acid bath in very real blue-tinged red tones colors.

Further examples of products to be manufactured according to the invention are given in the following table: In-shade on polyacrylonitrile with dimethyl sulfate game diazo component coupling component monoalkylated dye bisalkylated dye - 11 3-Amino-1,2,4-triazole 2-methyl-6-chloro-pyrazolo-yellow Reddish yellow [1,5-a] benzimidazole 12 the same. 2-phenyl-6-chloro-pyrazolo-red-tinged yellow strong red-tinged yellow [1,5-a] benzimidazole 13 3-amino-indazole 2-methylpyrazolo [1,5-a] - the same. benzimidazole 14 the same. 2-Phenylpyrazolo [1,5-a] - strongly reddish-tinged yellow, yellow-tinged orange benzimidazole continuation In-shade on polyacrylonitrile with dimethyl sulfate play diazo component coupling component monoalkylated dye bisalkylated dye 15 2-Amino-5-methyl-thiazole 2-methylpyrazolo [1,5-a] - yellowish red yellowish red benzimidazole 16 also 2-phenylpyrazolo [1,5-a] - red red benzimidazole 17 the same. 2-methyl-7-trifluoromethyl-yellowish red red pyrazolo [l, 5-a] benz- imidazole 18th 2-aminobenzothiazole 2- (3'-acetylaminophenyl) - bluish red Bordo pyrazolo [1,5-a] benz- imidazole Example 19 19 parts of methyl p-toluenesulfonate are gradually added to 36 parts of the azo dye from diazotized 2-aminobenzothiazole and 2-methylpyrazolo [5,1-b] quinazolone in 500 parts of o-dichlorobenzene at 100.degree. C. and then at 140 to 2 hours Stirred at 150 ° C. After cooling to 0 ° C., the monoalkylated dye is filtered off and dried. 52 parts of a dark brown-red powder which is sparingly soluble in water are obtained. From an aqueous dispersion, the dye dyes materials made of polyacrylonitrile in real reddish-tinged blue shades.

Example 20 52 parts of the dye obtained according to Example 19 are stirred into 1000 parts of water, the suspension is adjusted to pH = 8 to 9 with soda or sodium hydroxide solution and stirred at room temperature for 1 hour. The free dye base is then filtered off, washed with water and dried. 30.5 parts of a red-brown powder are obtained. 18.7 parts of the dye thus obtained are mixed with 200 parts of chlorobenzene, heated to 100 ° C. and 6.5 parts of dimethyl sulfate are gradually added. After stirring for a further 2 hours at 120 ° C., the mixture is cooled, filtered off and the dye is washed with benzene. After drying, 23 parts of a water-soluble bisalkylation product with an intensely blue-red color are obtained. The dye colors materials made of polyacrylonitrile or acrylonitrile-containing copolymers in very real blue-tinged red shades.

Example 21 37.4 parts of the azo dye from diazotized 2-amino - Benzthiazole and 2,4-dimethylpyrazolo- [5,1-b] quinazolone are chlorobenzene in 500 parts stirred and heated to 100 ° C. At this temperature it gradually becomes 12.6 parts Dimethyl sulfate was added and the mixture was stirred at 120 to 125 ° C. for 2 hours. After cooling down the dye formed is filtered off, washed with benzene and dried. Man contains 47 parts of a reaction product which is slightly water-soluble with a blue-red color, that from an acid bath containing materials made of polyacrylonitrile or acrylonitrile Mixed polymers dyes in very real blue-tinged red tones.

Further dyes which can be prepared according to the invention are listed in the table below. In-shade on polyacrylonitrile with dimethyl sulfate play diazo component coupling component monoalkylated dye bisalkylated dye 22 3-Amino-1,2,4-triazole 2-Methylpyrazolo [5,1-b] - Yellow Reddish yellow chinazolone 23 like. 2-Phenylpyrazolo [5,1-b] - reddish-tinged yellow like. chinazolone 24 like. 2-methyl-6-chloro-pyrazolo yellow like. [5,1-b] quinazolone 25 3-Aminoindazole 2-methylpyrazolo [5,1-b] - reddish yellow yellowish orange chinazolone 26 the same. 2-Phenylpyrazolo [5,1-b] - the same. The same. chinazolone 27 2-aminothiazole 2-methylpyrazolo [5,1-b] - red red chinazolone 28 also 2-phenylpyrazolo [5,1-b] - red red chinazolone 29 also. 2-methyl-7-chloro-pyrazolo-red red [5,1-b] quinazolone 30 2-Amino-4-methyl-2-methylpyrazolo [5,1-b] - Red Red thiazole quinazolone ' 31 same as 2,4-dimethylpyrazolo red red [5,1-b] quinazolone continuation In-shade on polyacrylonitrile with dimethyl sulfate Diazo component coupling component play monoalkylated dye bisalkylated dye 32 2-Amino-6-ethoxy-2-methylpyrazolo [5,1-b] - strong bluish red red-violet benzthiazole quinazolone 33 the same. 2,4-dimethylpyrazolo- the same. The same. [5,1-b] quinazolone 34 likewise. 2-methyl-6-acetylamino-red-violet violet pyrazolo [5,1-b] quinazolot. The dyes obtainable by the processes of Examples 1 to 10 and 19 and 20 correspond to the probable formulas

Claims (2)

Claims: 1. Process for the preparation of azo dyes, characterized in that sulfonic acid group-free azo dyes of the general formula where A stands for the radical of a five- or six-membered hetero ring, R, hydrogen, an alkyl or aryl radical, R2 is hydrogen or an alkyl radical, R3 is hydrogen or a substituent, X is a direct bond or the group and n denotes the number 1, 2 or 3, reacts with alkylating agents and, if appropriate, subjecting the dyes obtainable in this way to the action of alkylating agents a second time after alkaline treatment. 2. The method according to claim 1, characterized in that that the alkylating agent is alkyl, aralkyl or cycloalkyl halides, dialkyl sulfates or alkyl esters of aromatic sulfonic acids and the alkylation in organic Performs medium at elevated temperature. When announcing the registration a coloring table with explanations has been laid out.