Quinophthalone pigment

Quinophthalone colorants have a long history as dyes, especially as disperse dyes, acid dyes and paper dyes [2]. 

The first quinophthalone pigments were described in the 1960s. Table 19.1 shows the chemical composition of quinophthalone pigments known from the patent literature, the shades of the products and the dates of the relevant patent applications. 

High Performance Pigments. Edited by Edwin B. Faulkner and Russell J. Schwartz Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31405-S 

Quinophthalone (3) and its derivatives are normally products with good solubility in organic media. Neutral compounds like 3-hydroxyquinophthalone and its bro-minated derivatives are often used as disperse dyes for the coloration of polyester fibres [3] and styrenics. Sulfonated derivatives represent suitable anionic dyes for the coloration of wool, silk, paper and food. Products carrying basic side chains with quaternary nitrogen atoms are used for coloring paper [4]. 

Simple quinophthalone molecules are not suitable as pigments under standard application conditions in plastics and paints. In order to improve their resistance to solvents and migration several routes were followed  

Jacobson in 1882 fused phthalic anhydride with quinoline bases obtained from coal tar, which also contained quinaldine (136). He thus received quinophthalone (137). Quinophthalone derivatives bearing sulfonic or carboxylic acid functions represent suitable anionic dyes. Derivatives carrying basic side chains containing quarternary nitrogen, on the other hand, provide cationic dyes. The compounds are used especially as disperse dyes [1]. 

the parent structure to all pigments which are described in this chapter, continues to be prepared by fusion or, even better, by treating quinaldine with phthalic anhydride in an inert high boiling solvent at 200°C to 220°C. 

Although Eibner elucidated the structure between 1904 and 1906, it was only through IR and nuclear magnetic resonance spectroscopy (NMR) that the chro-maticity of these molecules could be attributed to keto-enol tautomerism and simultaneous hydrogen bond formation (structures 137a = 137b) [2]. 

Quinophthalone molecules are too soluble in various media to be used under normal application conditions. Both solvent and migration resistance may be enhanced by enlarging the molecule, and the options are as follows  

These methods produce yellow to red compounds which exhibit satisfactory pigment properties. 

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Quinophthalone pigments have a polycyclic structure derived from quinaldine and phthalic anhydride. 

Quinophthalone pigments are marketed in very limited number. The pigments provide yellow to red shades and are used primarily to color paints and plastics. 

P.Y.138 type quinophthalone pigments afford exceedingly lightfast and weather-fast greenish yellow shades with good heat stability. Their main fields of application are in paints and in plastics. 

Quinophthalones. The quinophthalone pigments are prepared by condensation of quinaldincs with a variety of aromatic anhydrides. One pigment in this series, Pigment Yellow 138, is a reasonably weatherfast greenish yellow pigment of good heat stability. The main field of application is paints and plastics. 

Quinophthalone pigments fall in the green shade yellow area and compete with cadmium yellow on a cost/performance basis. These pigments are suitable for rigid and flexible polyvinyl chloride (PVC), polyolefins, styrenics, acrylics, and polyurethane. They possess good resistance to chemicals, solvents, light, and heat (260-282°C). Transparent, semiopaque, and opaque versions are available. 

Quinophthalone Pigments 307, 310, 419 asymmetrical 310 manuFacture oF 310 Quinoxalinedione Pigments 419... 

Quinophthalone pigments are polycyclic compounds that derive their name from the parent compound quinophthalone (3), which was first synthesized by Jacobsen in 1882 by reacting quinaldine (1) with fused phthalic anhydride (2) (see Figure 19-1). ... 

The formation of the imide ring in PY 138 by reaction of the primary amino group with one mol of tetrachlorophthalic anhydride is faster than the formation of the phthalone ring. It is therefore possible to isolate 1 1 condensation products, which can be used as starting materials for asymmetrical quinophthalone pigments. So far products of this type have not been commercialized. 

The properties described above qualify quinophthalone pigments for applications including high quality industrial finishes, coloring of plastics and metal deco inks. Commercial products are supplied as powders, pigment preparations and liquid dispersions. 

Electrokinetic sonic amplitude (ESA) measurements (water / ethanol 4 1, Matec MBS 8000) show a very similar picture for the two quinophthalone pigments. They carry a very small negative charge and their isoelectric points are close to pH 3. Both pigments can be used in aqueous and solvent-borne systems. Erom the ESA-data (Table 19-4) it can be concluded that electrostatic forces play only a minor role in the stabilization of these systems. 

The first quinophthalone pigment appeared on the German market in 1973 Lithol Fast Yellow 1090, produced by BASF. 

Table 19-5 Known pigment brands and manufacturers of quinophthalone pigments f...

Quinophthalone pigments do not exhibit acute toxicity in animal tests by oral, dermal and inhalative application. Other tests have shown that they do not cause irritation of the skin or mucous membranes. The Ames test for mutagenicity gave negative results, while genotoxic testing shows no clastogenic effects. 

Quinophthalone pigments are poorly soluble in water. They exhibit practically no toxicity to fish and daphnia, as values determined for fish (orfe, acute, 48 h, ECso > 100 mg/L daphnia, EC50 > 100 mg/L) indicate. 

Table 19.1 Quinophthalone pigments known from the patent literature.

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