CH624424A5 - Process for the preparation of water-soluble azo dyes derived from 4,4'-diaminobenzanilide - Google Patents

Abstract

The process for the preparation of sulphonated azo dyes covered by the general formula: <IMAGE> where A is as defined in claim 1, comprises coupling a tetraazotised 4,4'-diaminobenzanilide in an alkaline medium with salicylic acid and in turn coupling the diazo-monoazo mass thus obtained in a substantially alkaline medium with the coupling element of the formula A, according to known techniques. The dyes thus obtained by diazotization and coupling of the said intermediate show application characteristics analogous to those of the direct dyes from the benzidine series, but their manufacturing process is free from the hazard of the toxicological risks which characterise the latter. These dyes show optimum wet fastness and light fastness properties and are used in direct dyeing of cotton and other cellulosic fibres such as linen, fibres of regenerated cellulose, hemp, jute and also natural and synthetic polyamide fibres and mixtures thereof, leather and other analogous materials.

Description

The present invention refers to a process for the preparation of a new series of sulphonated azo dyes suitable for the direct dyeing of cotton and other cellulosic fibers, such as linen, regenerated cellulose fibers, 65 hemp, jute and also natural and synthetic polyamide fibers and their blends, leather and other similar materials. The subject of the present patent application are water-soluble azo dyes of the general formula:

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i - (o) - n = n - <^ 0 ^) ~ conh - <^ 0 ^) - n = n cooh a

oh nh2

where A =

- n = n or / —n0-

HO3S

SO-jH D

or:

nii2

h2n o

ch3

- n = n - <

o / - soyi or:

0 Cu 0

n = n ~

ho soyi or:

or> -n = n- |

-n = n or o

- n = n -

or

- n = n-

it2n nh2

I know ^ h cooh

=, i - \ Q ^ ~ NH-co - (^ Q ^ - N = N - (5) -

SOOR

5

624424

The direct dyes mentioned above present application characteristics similar to those of the conventional direct dyes of the benzidine series, without however their manufacturing process involving particular toxicological risks. In fact, benzidine and its derivatives, which are used in the preparation of dyes having a structure similar to that of the invention, are dangerous substances for their carcinogenic effects and consequently their use and their preparation require rigorous environmental hygiene measures. The direct dyes of the general formula I are prepared by a process characterized in that a 4,4'-diaminobenzanilide tetraazotate is coupled in an alkaline medium with salicylic acid and that the diazo-monozoic mass thus obtained is in turn coupled in a medium substantially alkaline with the coupling element of formula A according to substantially known methods.

These dyes provide dark-toned dyes ranging from green to brown on cellulose, nitrogen and leather. The application in dyeing of the dyes of the general formula I is carried out with the same methods used for the direct benzidine dyes, that is at a temperature commonly comprised between 50 ° and 100 ° C, from an aqueous bath containing the appropriate quantities of dye and from 5 to 20% (with respect to the fiber weight) of anhydrous Na2SO4 or NaCl.

The following examples given by way of non-limiting example illustrate the invention.

Example 1

19.6 parts of sulphanilic acid suspended in 170 parts of water and 16,7 parts of HCl 20 ° Bé, and 100 parts of ice are diazotized at 0 ° C by pouring the solution of 7,8 parts NaN02 in 20-30 'in 20% solution (w / v).

The mixture is stirred for 2 hours and the excess of nitrous acid is destroyed with sulphamic acid. The diazotation mass is poured in 15 'on the solution of 12.2 parts of m. Toluene diamine in 200 parts of water, 100 parts of ice and 22 parts of HCl 20 ° Bé.

The pH is brought to 5.5-6 by dripping the solution of 20.7 g of NaHCO3 in 200 parts of water in Ih. It is left under stirring at night. The next morning it is heated to 40-45 ° C, 140 parts of aqueous solution of 10% Na2COa (w / w) are added: pH 9-9.5; when the solution is complete, it is cooled to 10 ° C with ice and then the 4,4'-diaminobenzanilide - salicylic acid diazo-monoazoic mass is added, prepared separately as indicated below. Temperature 10 ° C, pH ca. 8. It is left under stirring at night. In the morning it warms up to approx. 70 ° C is acidified with 28 parts of 20 ° Bé HCl and salt at 10% (w / v) with 300 parts of rock salt. It is vacuum filtered and washed with 10% brine. It squeezes carefully. The product obtained dried at 70-80 ° C for 24h dyes cellulosic fibers with a yellowish-brown hue.

The above mentioned diazo-monoazoic is prepared as follows.

22.7 parts of 4-4'-diaminobenzanilide, suspended in 100 parts of water and 52 parts of hydrochloric acid 20 ° Bé after cooling with 100 parts of ice are tetrazotized by dripping at 0-5 ° C of the solution of 14 parts of NaNOa in 60 parts of water. After 60 'of stirring, the excess of nitrous acid is eliminated with sulphamic acid.

15 parts of salicylic acid dissolve in 150 parts of H20 and 14.6 parts of NaOH 36 ° Bé. The solution obtained, added with 5 parts of Na2CO, g, as a 20% (w / v) solution and cooled to 0-2 ° C with 50 parts of ice, is quickly added (~ 2 ') to the mass of the tetrazo. 15 parts of Na2CQ3 are poured into Ih as a 20% (w / v) solution. Temperature 0-2 ° C, pH ca. 9. Shake for 2h at the end.

Example 2

18.9 parts of 2-amino-phenol-4-sulfonic acid suspended in

150 parts of water and 10.5 parts of hydrochloric acid 20 ° Bé are cooled with 100 parts of ice and at 0-5 ° C they are diazotized by dripping in 30 'of the solution of 7 parts of NaNOa in 30 parts of H2O.

5 After stirring for 60 'the excess of nitrous acid is eliminated with sulphamic acid.

11.6 parts of resorcin dissolve in 70 parts of water and 13.3 parts of NaOH 36 ° Bé. On the obtained solution the diazotation mass is poured into Ih keeping the temperature io at 0-5 ° C with 150 parts of ice and the pH at about 9 with 26.5 parts of NaOH 36 ° Bé. The mixture is left under stirring to complete the copulation and then the solution of 26 parts of CuS04 is added. 5HaO in 80 parts of H20 at 70 ° C; 8 parts of Na acetate are added. 3h20. It is kept for 3 hours 15 at 35-40 ° C and pH 5-5.5. We salt at 6% (w / v) with 45 parts of rock salt; the precipitate obtained is filtered empty and squeezed carefully. The cake is taken up in 150 parts of water at 40 ° C and solubilized by adding a solution of 15 parts of Na2CO: in 70 parts of H2O, at pH approx. 9. Maintaining the 2nd temperature at 10-15 ° C, pour 4,4'-diaminobenzanilide - salicylic acid on the mass of diazo-monoazoic acid, prepared separately according to Example 1.

It is left under stirring at night. The following morning it is heated to 60-70 ° C, acidified to light Congo Red with 25 hydrochloric acid 20 ° Bé. It is filtered empty and the panel is carefully squeezed.

The product obtained, dried at 70-80 ° C, can be applied in dyeing and printing on cellulosic fibers with a reddish brown shade of excellent wet and light fastness.

30

Example 3

13.8 parts of p-nitroaniline are suspended in 50 parts of H20 and 35 parts of HCl 20 ° Bé. 100 parts of ice and diazota are added by rapidly pouring in a solution 35 at 20% (w / v) of 7 g of NaN02, at a temperature of 10 ° C. The mixture is left under stirring for 30 minutes. On the clarified solution of the diazo, the solution of 39 parts of acid H in 150 parts of H2O and 14.6 parts of NaOH 36 ° Bé is poured in 45 'at 0-5 ° C. pH 0.8-1.1. The mixture is left under stirring overnight and then poured onto the mass 40 of diazo-monoazoic 4-4'-diaminobenzanilide - salicylic acid prepared separately according to example 1. 50 parts of ice are added and the pH is brought to 8, 5-9 with 16 parts of Na2C03 dissolved in 70 parts of H20. It is left to stir at night. In the morning it is heated to 70 ° C and filtered empty. Panel 45 squeezes carefully. It dries at 80-90 ° C.

The product obtained dyes cellulosic and polyamide fibers in a bluish green tone with excellent wet and light fastness.

Example 4

20.4 parts of 4-4'-diaminobenzanilide, suspended in 45 parts of H20 and 52 parts of HCl 20 ° Bé, after cooling with 200 parts of ice are tetrazotized by dripping the solution of 12 at 0-5 ° C, 5 parts of NaNOa in 50 parts of H20. The mixture is left under stirring for 1 hour at pH 1-1.5. Excess nitrous acid with sulphamic acid is removed.

13.5 parts of salicylic acid dissolve in 180 parts of H2O and 6.5 parts of Na2CO; J. pH 7.5. 100 parts of ice are added and poured flush over the tetrazotation mass. The pH is raised to 99.5 with 29 parts of Na2-C03. The mixture is left in 60 stirring at 0.5 ° C for 3 hours and the solution of 17.2 parts of l-naphthylamino-6/7 sulfonic acid dissolved in 270 parts of H20 at 40 ° C and 9.3 parts of NaOH 36 ° Well and cooled with 100 parts of ice. It is left under stirring at night. The next morning the pH is brought to 2.5 with 42 parts 65 of HCl 20 ° Bé; after 15 'of stirring the pH is raised to 8.5 with 22.5 parts of NaOH 36 ° Bé to complete the copulation. The mass is added with 200 parts of ice, 60 parts of H2S04 60 ° Bé and is slowly dizzy by dripping

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below level the solution of 11.5 parts of NaNO, in 50 parts of H, 0. The mixture is left under stirring until the next day, the excess of nitrous acid with sulphamic acid is eliminated and the suspension obtained as described below is added:

16.3 parts of m.phenylenediamine dissolve in 330 parts of water and bring to pH 5-5.5 with a little 20 ° Bé HCl. 270 parts of ice, 7.2 parts of sodium nitrite are added and 26.1 parts of 20 ° Bé HCl diluted with 26.1 parts of HaO are dropped under level in 3 hours. There is weak acidity in Rosso Congo. The mixture is left under room temperature until stirring until the next day.

The mass rises to 17% with rock salt (135 parts), the precipitated dye is filtered empty and squeezed carefully. The cake is suspended in 400 parts of H., 0 at 90 ° C, homogenized and then cooled with 300 parts of ice. 5 The copulation mass is brought to pH 7.5 with 120 parts of NaOH 36 ° Bé and is left under stirring until the next day. The mixture is heated to 70 ° C and salted at 3% (w / v) with 90 parts of rock salt. It is filtered empty and squeezed carefully. It dries at 80 ° C. The dye obtained dyes cellulosic fibers in brown tones with good solidity characteristics.

v

Claims (5)

624424 # 2 crn TT Process according to claim 1, wherein A is: to f2 aa 2 CLAIMS 1. Process for the preparation of sulphonated azo dyes included in the general formula: h0 - (5) - n = n — c ° nh ~ ^ 0 ^) "n = n cooh - TO where A is: or: OH NH ' Oto - n = n - / o) —no. hozs' 5 > 0, H (THE) or: nh, or n = n - H2N i ^ ch Process according to claim 1, wherein A is: ho3s SO ^ H characterized in that the diazomonoazoic mass obtained is coupled with the diazo compound obtained from the diazotized p-nitroaniline and coupled in acid medium with "H acid". n = n SO ^ H 10 characterized in that the diazomonoazoic mass obtained is coupled with the diazo compound obtained from 5 diazotized sulphanilic acid and coupled with m-toluilen - diamine in acid medium. 3 624424 characterized in that a 4,4'-diaminobenzanilide tetra-nitrogen is coupled in an alkaline medium with salicylic acid and that the diazo-monoazoic mass thus obtained is in turn coupled in a substantially alkaline medium with the coupling element of formula A. 3 or: 0 Cu 0! or - N = N _ or I HAVE - (o / n = n ■ or SO ^ H ■ n = n - v'nsn-, or - n = N> ~ N = SOyi ii2n nh2 COOH = "■ (5y nh ~ co- (5> - H = li - / o> - 011 Process according to claim 1, wherein A is: 20 25 I have characterized in that the obtained diazo-monoazoic mass is coupled with the diazo compound obtained from the diazotized 2-amino-phenol-4-sulfonic acid and coupled in alkaline medium with resorcin added with copper sulphate pentahydrate. 35 5. Process according to claim 1, wherein A is: it is characterized in that the obtained diazo-monoazoic mass is first coupled in alkaline medium with l-naphthylamino-6- or -7-sulphenic acid, and that the obtained mass is diazotized and coupled in substantially alkaline medium with tetra-nitrogen m-phenylenediamine and coupled in 55 acid medium.