Synthesis of Iodine-Containing Monoazo Dyes
Abstract Generated abstract
This paper reports the preparation of iodine-containing monoazo dyes intended to explore the effect of halogen substitution on dye properties. The authors synthesized p-iodoaniline and 4,4'-iodoaminodiphenyl derivatives, diazotized them, and coupled each diazo component with phenol, beta-naphthol, chromotropic acid, and H-acid. Eight previously undescribed dyes were obtained, and their water solubility and fastness to soap, soda, washing, rubbing, and perspiration were tabulated. The results indicate that dyes derived from phenol and beta-naphthol were water-insoluble and generally showed higher fastness than those based on chromotropic acid or H-acid.
Full Text
Synthesis of Iodine-Containing Monoazo Dyes
A. M. Sedov, A. A. Sergeeva, A. N. Novikov
(Presented by the scientific-methodological seminar of the Chemical-Technological Faculty)
It is known that, in obtaining certain dyes, halogens have been introduced in order to shift the shade in one direction or another [1].
Thus, for example, a dye based on 3-iodoaniline and perylene-tetracarboxylic-3,4,9,10-acid surpasses the iodine-free dye in purity and brightness. The dyeings possess high fastness to light, oils, and migration into solvents [2].
Proceeding from the few literature data, we undertook the synthesis of iodine-containing monoazo dyes, using p-iodoaniline and 4,4′-iodoaminodiphenyl as the diazo components. The iodoamino compounds necessary for diazotization were obtained by reduction of p-iodonitrobenzene and 4,4′-iodonitrodiphenyl [3, 4]; the corresponding iodonitro compounds were synthesized from benzene and diphenyl by the combined action on them of iodine and a sulfuric–nitric acid mixture.
Experimental Part
Diazotized p-iodoaniline and 4,4′-iodoaminodiphenyl were coupled, each separately, with H-acid, chromotropic acid, β-naphthol, and phenol.
Example 1. Coupling of diazotized p-iodoaniline with chromotropic acid.
5.1 g of p-iodoaniline was dissolved in a mixture of 10.5 ml of concentrated hydrochloric acid and 250 ml of water and cooled with ice to 0°C. Then, with stirring, a solution of 2 g of sodium nitrite in 8 ml of water was added to the resulting solution of p-iodoaniline. After 30 min of stirring, the diazo solution was added to a solution, cooled to 0°C, of 8 g of chromotropic acid and 13 g of sodium acetate in 50 ml of water, and the resulting mixture was stirred for another 3–4 hours at +5–7°C. The dye was salted out with sodium chloride and filtered off. Yield of the monoazo dye: 9–11 g.
Example 2. Coupling of diazotized 4,4′-iodoaminodiphenyl with β-naphthol.
3.4 g of 4,4′-iodoaminodiphenyl was dissolved in a mixture of 7 ml of concentrated hydrochloric acid and 50 ml of water. The solution was cooled to 0°C by adding ice. Then a solution of 2.5 g of sodium nitrite in 10 ml of water was added to this solution, and after 30 min of stirring 15 g of sodium chloride was added. The diazo solution was added, with stirring, to a cooled solution of β-naphthol, obtained by dissolving 7.2 g of β-naphthol at 60°C in 110 ml of a 2% sodium hydroxide solution. After
After addition of the diazo solution, the mixture was stirred for another 1 hour. The dye was salted out and filtered off. The yield of the monoazo dye was 7–8 g.
Monoazo dyes with other azo components were obtained analogously. Some characteristics of the iodine-containing monoazo dyes obtained are given in Table 1.
Table 1
Characteristics of iodine-containing monoazo dyes
| Diazo component of the dye | Azo component of the dye | Solubility in water | Fastness of dyeings, points: to soap | Fastness of dyeings, points: to soda | Fastness of dyeings, points: to washing | Fastness of dyeings, points: to rubbing | Fastness of dyeings, points: to perspiration |
|---|---|---|---|---|---|---|---|
| p-Iodoaniline | phenol | insol. | 5/5 | 5/5 | 5/5 | 5/3 | 5/5 |
| p-Iodoaniline | beta-naphthol | insol. | 5/5 | 5/4 | 5/5 | 5/4 | 5/4 |
| p-Iodoaniline | chromotropic acid | sol. | 3/4 | 3/4 | 3/4 | 4/2 | 3/4 |
| p-Iodoaniline | H-acid | sol. | 3/3 | 3/1 | 3/3 | 5/3 | 3/2 |
| 4,4'-Iodoaminodiphenyl | phenol | insol. | 5/5 | 5/5 | 5/5 | 5/4 | 5/4 |
| 4,4'-Iodoaminodiphenyl | beta-naphthol | insol. | 5/5 | 5/5 | 5/4 | 4/4 | 5/5 |
| 4,4'-Iodoaminodiphenyl | chromotropic acid | sol. | 3/4 | 3/5 | 3/4 | 5/2 | 3/3 |
| 4,4'-Iodoaminodiphenyl | H-acid | sol. | 3/3 | 1/2 | 3/2 | 4/1 | 3/2 |
Conclusions
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Eight iodine-containing monoazo dyes not described in the literature were obtained with the diazo components p-iodoaniline and 4,4'-iodoaminodiphenyl and with the azo components chromotropic acid, H-acid, beta-naphthol, and phenol.
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Monoazo dyes with the azo components beta-naphthol and phenol possess high fastness.
References
- E. Leibmitz, H. Iheurer, Journal of General Chemistry, 34, 140, 1953–54.
- W. Eckert. German Federal Republic Patent, 1105084, 30, 11, 1961.
- F. Griss. Zeitschrift für Chemie, 218, 1866.
- W. Teilacker, W. Berger, P. Popper, Chem. Ber., 89, 4, 970 (1956).