Phthalocyanine dyestuffs

Approximately 90% of the phthalocyanines (predominantly copper phthalocyanine) are used as pigments (qv). In addition, they have found acceptance in many types of dyestuffs, eg, direct and reactive dyes, water-soluble and solvent-soluble dyes with physical and chemical binding, a2o-reactive dyes, a2o nonreactive dyes, sulfur dyes, and vat dyes (1) (see Dyes Dyes, reactive). 

Phthalocyanine Dyes. In addition to their use as pigments, the phthalocyanines have found widespread appHcation as dyestuffs, eg, direct and reactive dyes, water-soluble dyes with physical or chemical binding, solvent-soluble dyes with physical or chemical binding, a2o reactive dyes, a2o nonreactive dyes, sulfur dyes, and wet dyes. The first phthalocyanine dyes were used in the early 1930s to dye textiles like cotton (qv). The water-soluble forms Hke sodium salts of copper phthalocyanine disulfonic acid. Direct Blue 86 [1330-38-7] (Cl 74180), Direct Blue 87 [1330-39-8] (Cl 74200), Acid Blue 249 [36485-85-5] (Cl 74220), and their derivatives are used to dye natural and synthetic textiles (qv), paper, and leather (qv). The sodium salt of cobalt phthalocyanine, ie. Vat Blue 29 [1328-50-3] (Cl 74140) is mostly appHed to ceUulose fibers (qv). 

Air oxidation of dyestuff waste streams has been accompHshed using cobalt phthalocyanine sulfonate catalysts (176). Aluminum has been colored with copper phthalocyanine sulfonate (177,178). Iron phthalocyanine can be used as a drier in wood oil and linseed oil paints (179). 

Phthalocyanine Dyes. The phthalocyanine molecule is much too big to be used on hydrophobic fibers and therefore is only used in its sulfonated form as the basis for direct and reactive dyes (see Phthalocyanine compounds). Its forces of attraction are different from a small linear yeUow a2o dye with which it is used to form bright greens. CompatibiHty between the two is likely to be a problem in practice and to overcome this, green dyestuffs containing a phthalocyanine dye linked via a saturated chromophore blocker (—x—) have been made, eg,... 

The chemical nature of most organic pigments is closely similar to that of the synthetic dyes that have been discovered during the past 150 years. In fact, with the exception of the phthalocyanines, almost every chemical class of pigments has been developed first for dyestuff use. There are some signs that this may not continue to be the case, with the development of some new organic pigments for specialised uses. 

There are many organic dyestuffs but only one class, that of the metal chelates, has been found to be active in electrocatalysis. The first compounds described were the phthalocyanines 1-4), which are similar in structure to the heme in the blood pigment, hemoglobin in both, the metal atom is surrounded by four nitrogen ligands. 

The importance of phthalocyanines, apart from their early use as models for hemes and chlorophylls, lies in the fact that metal complexes of the phthalocyanine system produce extremely intense and useful dyestuffs. Much research has therefore been devoted to physical and spectroscopic studies of these molecules (B-81MI30700). Phthalocyanines are extremely stable, are stable to light, and are insoluble in most solvents, so they are very useful dyestuffs. 

The first prerequisite for copper phthalocyanine-based dyestuffs was the production of water-soluble derivatives and this was made possible by the resistance of the parent compound to chemical degradation. Thus, treatment of copper phthalocyanine with 26% oleum first at 45 °C and then at 60 °C for 12 hours gives the water-soluble disulfonic add (225) which was the first commercial... 

Metal-dye complexes play a very important role in dyestuff technology and find applications in many other fields, e.g. in analytical chemistry.119-123 Except for copper phthalocyanine, metal-azo compound complexes are the most important and the most widely used as dyes and pigments. Typical precursors are shown in Scheme 1. 

The phosgene cyclization derivative, benzimidazalone (2-hydroxybenzlmidazole), is also employed in dyestuffs manufacture, and phthalonitrile (used in the preparation of copper phthalocyanine) has also been prepared by the dehydration of phthalamide using phosgene. 

The phthalocyanine macrocyclic system, formally derived from four isoindoles, is the basis for many blue dyestuffs. Metal derivatives have a cation complexed at the centre, much like the iron atom in heme (see... 

Copper phthalocyanine is a dark blue, extremely stable compound which sublimes at 500°C without decomposition. It is not affected by heating in hydrochloric acid or potassium hydroxide. Copper phthalocyanine can be chlorinated or sulfonated. Its chlorination products (replacement of 14-16H by Cl) are green. Copper phthalocyanine and its substitution products are important as pigments in the dyestuff industry. 

The phthalocyanine macrocyclic system, formally derived from four isoindoles, is the basis for many blue dyestuffs. Metal derivatives have a cation complexed at the centre, much as the iron atom in haem. Phthalocyanine can be produced by the reductive cyclisation of 2-cyanobenzamide or, in a route which makes its relationship to isoindole more obvious, by the combination of four molecules of 1,3-diiminoisoindoline with the elimination of ammonia. ... 

The incorporation of phthalocyanines into a multichromophore supra-molecular system was attempted by attachment to imidazolyl zinc porphyrin 65 (Fig. 28). A combination of strong absorption of the Soret band of porphyrin and of the Q-band of phthalocyanine makes compound 66 an attractive dyestuff similar to chlorophylls and covering the whole visible re-... 

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