ON THE APPLICATION OF NITROSO DERIVATIVES OF CARBAZOLE IN THE DYEING OF TEXTILE FIBERS

L. P. Kulev, V. P. Lopatinskii

In previous works one of us established that the hydrochloride salts of \(n\)-nitrosodimethylaniline and \(n\)-nitrosodiphenylamine possess the ability to condense on textile fibers with the formation of yellow-orange, brown, and black dyes [1, 2, 3]. Dyeing is readily carried out by boiling the material to be dyed for 20–30 minutes in an aqueous solution of the nitroso product; the dyeings are distinguished by high lightfastness. Attempts to establish the structure of the dyes formed on the fiber were not successful, since in the course of dyeing a mixture of compounds of varying degrees of complexity is formed, the final products of which are black dyes. Nevertheless, the study of one of the condensation products of \(n\)-nitrosodiphenylamine gives grounds for asserting that it belongs to the class of azine dyes. Since carbazole may be regarded as a derivative of diphenylamine, it is natural to expect that nitroso derivatives of carbazole should possess analogous properties. However, the poor solubility of \(N\)-nitroso- and 3-nitrosocarbazoles in water impeded the process of dye formation directly on the fiber, and by this route it was not possible to obtain satisfactory results. The use of nitrosocarbazoles in condensation reactions with aromatic amines and phenols proved more successful.

Experiments showed that, upon brief boiling (30–40 minutes) of animal fibers and acetate silk in water with a mixture of nitrosocarbazole and an aromatic amine or phenol in an acidic medium, dyeings of yellow, orange, reddish-brown, and brown-black colors are formed. The colors of the dyeings on the fabric gradually deepen as the duration of boiling is increased. However, the final color depends on the initial amino or hydroxy compound and does not change when the boiling time is prolonged beyond 30–40 minutes. These facts make it possible to conclude that we are dealing with different dyes, in the formation of which both starting products take part, i.e., nitrosocarbazole and the aromatic amine or phenol.

The mechanism of the condensation reaction may be represented as follows. \(N\)-Nitrosocarbazole in hydrochloric acid medium rearranges into 3-nitrosocarbazole [4], which can react in the isonitroso form (quinone oxime) [5]:

\[ \text{N-nitrosocarbazole} \ \xrightarrow{(+\mathrm{HCl})}\ \text{3-nitrosocarbazole} \ \rightleftharpoons\ \text{isonitroso form (quinone oxime)} \]

In the presence of acids the isonitroso product condenses with aromatic amines and phenols, forming quinone-imine dyes, for example:

The condensation product formed on the fabric and apparently having structure (III) gives, in our experiments, the deepest, almost black dyeings. The brown color of the dyeings corresponds to structure (II) of the dye from resorcinol and nitrosocarbazole, which is confirmed by the results of elemental analysis.

It is characteristic that dyeings of the same shades can be obtained both from 3-nitroso- and from \(N\)-nitrosocarbazole. This confirms our assumption that, under the conditions of the experiments (heating in the presence of hydrochloric acid), \(N\)-nitrosocarbazole is converted into 3-nitrosocarbazole, which then reacts with amines and phenols to form dyes. In this way it was possible to obtain fast dyeings only on animal fibers and acetate silk; dyeings on cotton were dull and not fast to light and washing.

Attempts to isolate the dyes from the dye bath were unsuccessful, since that part of the dyes which was not taken up by the fiber underwent rapid resinification. The best results were obtained by heating the starting substances in an acidified benzene solution. In this way, for example, a dye was isolated from \(N\)-nitrosocarbazole and resorcinol (II).

Experimental Part

Carbazole. The starting carbazole was isolated from crude anthracene from the Kemerovo Coke-Chemical Plant by the formaldehyde method [6] and, after several recrystallizations from alcohol, had m.p. \(243\text{--}244^\circ\mathrm{C}\).

\(N\)-Nitrosocarbazole. To obtain \(N\)-nitrosocarbazole, the procedure of V. Khmelevskii and I. Levin [7] was used. The product, recrystallized from alcohol, had the appearance of golden-yellow leaflets and melted at \(83\text{--}83.5^\circ\mathrm{C}\).

3-Nitrosocarbazole. 3-Nitrosocarbazole was obtained from \(N\)-nitrosocarbazole by the method of G. Schott [8]. The product, dried over \(\mathrm{CaCl_2}\), was a dark-green amorphous powder without a definite melting point, readily soluble in alcohol, acetic acid, benzene, and ether.

Dye from \(N\)-nitrosocarbazole and resorcinol. In the experiments, resorcinol with m.p. \(110^\circ\mathrm{C}\), obtained after double recrystallization from benzene in the form of slightly yellowish needles, was used. \(5\ \mathrm{g}\) of \(N\)-nitrosocarbazole and \(2.8\ \mathrm{g}\) of resorcinol were dissolved at \(20^\circ\mathrm{C}\) in \(50\ \mathrm{ml}\) of benzene; then 5–10 drops of concentrated hydrochloric acid (specific gravity 1.19) were added, and the mixture was carefully heated on a water bath. Already at \(30^\circ\mathrm{C}\), formation of a precipitate was observed on the walls of the reaction flask; as heating proceeded, it separated out…

from the reaction mass in the form of dark-red flakes. To complete the reaction, the mixture was boiled for 5 minutes and, after cooling, 20 ml of distilled water was added to it. After careful evaporation of the water from the dark-red solution, crystals of the dye precipitated. The dry crystals had a grayish-black color with a violet shade, dissolved in water, and had no definite melting point. Yield—2.5 g (34.1%). The same dye was obtained from 3-nitrosocarbazole and resorcinol, but in lower yields (10–12%).

Results of analyses:
0.2063 g substance: 0.5710 g CO₂; 0.0628 g H₂O. 0.1279 g substance: 11.2 ml N₂ (21°C, 765 mm). Found, %: C 75.54; H 3.41; N 10.14. C₁₈H₁₀O₂N₂.
Calculated, %: C 75.56; H 3.49; N 9.79.

Experiments on the Dyeing of Natural and Acetate Silk

The dyeing of animal fibers and acetate silk was carried out by two methods. In the first method, dyeings were obtained directly on the fiber by boiling fabric samples in acidified water containing \(N\)-nitroso- or 3-nitrosocarbazole and one of the following substances: resorcinol, pyrogallol, gallic acid, \(m\)-phenylenediamine.

In the second method, the dye was first synthesized from the components, and dyeing was carried out from an aqueous solution of the dye. For dyeing by this method, only the dye obtained from nitrosocarbazole and resorcinol was used.

Experiments on Obtaining Dyeings Directly on Animal Fibers and Acetate Silk

The dyeing procedure by this method was as follows. Dry \(N\)-nitroso- (or 3-nitroso)-carbazole and the amino (or oxy) compound, taken in equimolecular ratios, were thoroughly mixed, and the mixture was shaken in water at room temperature. The dye bath was acidified, brought to boiling, and a fabric sample previously wetted with water was immersed in it. Boiling was continued for 10–60 minutes. Formation of the dye occurred both on the fiber and outside it. The color of the solution gradually deepened simultaneously with the deepening of the color of the dyeings. After dyeing, the fabric was washed and dried.

1. Dyeing with the condensation product of \(N\)-nitroso- (or 3-nitroso)-carbazole with resorcinol.

Equimolecular amounts of \(N\)-nitroso- (or 3-nitroso)-carbazole and resorcinol, after thorough mixing, were boiled in acidified water (1 g of mixture per 50 ml H₂O) with fabric samples (bath ratio 1:50). The color of the solution changed from light yellow (5 min boiling) to reddish-brown (30 min) and did not deepen further. At the same time, the color of the dyeings on the fabric also changed from yellow-orange (10 min boiling), through dark-orange (20 min), to brownish-black (30 min). Further boiling did not deepen the color of the dyeings.

1. Dyeing with the condensation product of \(N\)-nitroso- (or 3-nitroso)-carbazole with pyrogallol.

Dyeing was carried out according to the procedure described above. The color of the solution gradually changed from yellow to red-brown, becoming brown upon cooling of the solution. The shades of the dyeings changed from light yellow-brown (15 min boiling), through light-brown (30 min), to dark-brown (60 min).

1. Dyeing with the condensation product of N-nitroso- (or 3-nitroso-) carbazole with gallic acid.

Dyeing was carried out under the previous conditions; however, the color of the solution and of the dyeings, at the same boiling time, remained lighter than when pyrogallol was used. The deepest dyeings in color were yellow-brown (after 15 min boiling).

1. Dyeing with the condensation product of N-nitroso- (or 3-nitroso-) carbazole with m-phenylenediamine.

Dyeing was carried out under the same conditions. The color of the bath changed from light yellow to orange. Increasing the duration of boiling from 10 to 60 minutes did not deepen the dark-yellow color of the dyeings.

Experiments on dyeing animal fibers and acetate silk with a dye from N-nitrosocarbazole and resorcinol

Dyeing was carried out in a bath containing 1 g of dye per 50 ml of water (bath ratio 1:50), without acidification. On boiling, the color of the solution became intensely red with a violet shade, and on cooling—red-brown. Boiling fabric samples in the dye solution for 5–10 minutes gave brown dyeings with a reddish shade, which, after boiling for more than 30 minutes, became dark brown.

Determination of the fastness of dyeings of dyes from N-nitrosocarbazole and resorcinol

The fastness of the dyeings to light and weather was determined according to GOST 10085—39 [9]. The test and standard samples were exposed simultaneously in an open sunny place for two summer months (July–August). The tests showed good fastness of the dyeings, equal to 4 points.

Conclusions

1. The dyeing properties of a new group of quinone-imine dyes, obtained by the condensation of N-(and 3-)nitrosocarbazoles with aromatic amines and phenols and forming dyeings directly on the fiber from yellow to brown colors, have been investigated.

2. An oxazine dye from N-nitrosocarbazole and resorcinol has been isolated and studied; on animal fibers and acetate silk it gives lightfast dyeings of a brown-black color.

LITERATURE

1. Kulev L. P., Nikiforova O. K. Trudy Khimiko-metallurg. in-ta ZSFAN, issue 4, 13, 1950.

2. Nikiforova O. K. Trudy Khimiko-metallurg. in-ta ZSFAN, issue 4, 21, 1950.

3. Kulev L. P., Stepnova G. M., Kristalev P. V. Izvestiya TPI, 77, 141, 1953.

4. Zeidler O. Ann. 191, 285, 1878.

5. Vorozhtsov N. N. Fundamentals of the Synthesis of Intermediate Products and Dyes, 4th ed., GKhI, 1955.

6. Maksorov B. V. ZhKhP, 6, 41, 1929.

7. Khmelevskii V. I., Levin I. S. POKh, 7, 308, 1940.

8. Schott H., German patent 134983, 1901; Friedländer 6, 61, 1904.

9. Collection of Standards and Technical Specifications for Products of the Chemical Industry, issue III, Standartgiz, 1949.