Лако-красочные материалы — производство

As a class, the dyes are bright and strong, but are generally deficient in lightfast­ness. Consequently, they are used in outlets where brightness and cost-effective­ness, rather than permanence, are paramount, for example, the coloration of paper. Many dyes of this class, especially derivatives of pyronines (xanthenes) are among the most fluorescent dyes known (see later).

Typical dyes are the diphenylmethane Auramine O (28; R = CH3, X = C-NH 2; C. I. Basic Yellow 2); the triphenylmethane Malachite Green (27; R = CH3; R’ = H; C. I. Basic Green 4 ); the thiazine dye Methylene Blue (30; R = CH3; C. I. Basic Blue 9) used extensively in the Gram staining test for bacteria; the oxazine dye C. I. Basic Blue 3 (31; R = C2H5), and the xanthene dye C. I. Acid Red 52 (32). The bright magenta dye (32) is used in several ink-jet magenta inks, normally to improve the chroma (vividness).

The structural interrelationships of the diarylcarbenium dyes (26), triarylcar — benium dyes (27) and their heterocyclic derivatives are shown in Figure 2.6.

2.6.2 References

[1] J. Griffiths: Colour and Constitution of Organic Molecules, Academic Press, London, 1976, p. 250.

[2] J. Fabian, H. Hartmann: “Light Absorption of Organic Colorants”, Reactivity and Structure Conceptsin Organic Chemistry, vol. 12, Springer Verlag, Berlin, 1980, p. 137.

[3] H. Zollinger: Color Chemistry, 2nd ed., VCH Verlagsgesellschaft, Weinheim, 1991, p. 71.

[4] J. Griffiths, K. J. Pender, Dyes Pigm. 2 (1981) 37.

[5] C. Reichardt: Solvents and Solvent Effects in Organic Chemistry, 2nd ed., VCH Ver­lagsgesellschaft, Weinheim 1988, p. 107.

[6] Hoechst, DE 1 098 652, 1956.

[7] Hoechst, DE 1644 619, 1967.

[8] Dahl, DE 36 900, 1886.

[9] ICI, DE 508 499, 1929.

[10] Hoechst, DE 2 460 491, 1974 (M. Haehnke, F. Kohlhaas, F. Meininger, T. Papenfuhs).

[11] Hoechst, DE 2 344 443, 1973 (R. Neeb, T. Papenfuhs).