Лако-красочные материалы — производство

The intra — and intermolecular arrangements of the DPP molecules in a DPP crys­tal have been investigated by single X-ray structure analysis [22-28]. Angles and bond distances in the diphenyl DPP 2 are shown in Figure 11.3. The DPP molecule is practically planar, the phenyl rings being twisted out of the heterocyclic plane by only […]

Like many other pigment classes, DPP pigments fluoresce in solution. The Stokes shifts are in the range of 10-15 nm and the fluorescence quantum yields ca. 60% [16]. In the solid state, some DPPs show a minor fluorescence. Through N substi­tution, both the solubility and the Stokes shift can be increased. Some specific N-substituted DPP […]

During investigations to synthesize N, N’-substituted DPP derivatives, Langhals et al. have been able to condense the diketofurofurane 8 with anilines in the pres­ence of dicyclohexylcarbodiimide (DCC) and isolate the tetraphenyl DPP 9 in 46% yield (Scheme 11.6, top) [9]. An alternative approach to N, N’-diaryl DPPs 9A is based on the classical Stobbe condensation […]

A second new route to DPP Pigments was developed and published in 1983 [5, 6]. In this route, a succinic ester is condensed in a pseudo-Stobbe condensation with an aromatic nitrile in the presence of strong base to afford the desired DPP in good yield (Scheme 11.4). Mechanistically, the formation of a DPP unit from […]

Several syntheses of the diketopyrrolopyrrole skeleton have been described in the lit­erature. In the following sections, different syntheses published are summarized. 11.2.1 Reformatsky Route In the original publication [1] describing the first DPP synthesis (Scheme 11.1) via a Reformatsky reaction, the authors postulated that the formation of the DPP 2 proceed via an oxidative dimerisation […]

OlofWallquist and Roman Lenz 11.1 Introduction This chapter summarizes the scientific, technological, and applicatory know-how on diketopyrrolopyrrole (DPP) pigments available in the literature since their first appearance in 1974 up to about mid 2006. Emphasis is placed on the chemistry, properties, and applications. History In 1974, Farnum et al. [1] briefly reported on the attempted […]

Because of their physicochemical properties benzimidazolone pigments represent an extremely low toxicological and environmental risk. Like other azo pigments, the benzimidazolone pigments have very high oral LD50 values. Exposure to fine dust should however be avoided in the workplace, and normal industrial hygiene procedures for handling chemicals should be practiced. References

Benzimidazolone pigments first appeared on the German market in 1964. The relative order in which the seventeen generic structures, still available as pigments from Clariant, were launched in Europe, is listed in Table 10.3. As mentioned above, there are numerous manufacturers of benzimidazolone pigments today. Since the introduction of this pigment class, they have successfully […]

The properties described qualify benzimidazolone pigments for applications such as high quality industrial paints, including automotive finishes and special effect paints, plastics and high performance printing inks. The colorants are available in the form of powders, masterbatches, liquid dispersions, pastes and granules (see Table 10.4). Table 10.2 Spectrometric data of five commercially available benzimidazolone pigments. […]

Benzimidazolone pigments cover a broad spectral range from very greenish yellow through orange, red and violet to brown. The tinctorial strength of the pigments pre­pared varies considerably because oftheir different physical characteristics. This fact does not surprise us, as the median of the particle size distribution ranges from 50 nm to 1000 nm (compare Table […]