Perylenes pigments

Perylenes. Perylene pigments are either the 3,4,9,10-tetracarboxyhc dianhydride or more often N,N -substituted diknides (Table 7). 

Perylene Pigments. The perylenes ate a class of red and maroon pigments. In the general formula, Rmay represent a simple alkyl, methyl, or a substituted phenyl, eg, PR 123, R = p-ethoxyphenyl. 

Pervaporation systems, 15 798 Perxenates, 17 326 Perylene Green (Yellow), colorant for plastics, 7 374t Perylene pigments, 19 443 commercial, 19 444t Perylene Red... 

Perylene pigments include the dianhydride and diimide of perylene tetracarboxylic acid along with derivatives of the diimide while perinone pigments are derived from naphthalene tetracarboxylic acid. 

P.R.206 is a mixed crystal type and consists of unsubstituted quinacridone and quinacridone quinone. The ratio between the two components as well as the crystal modification is not yet known. P.R.206 affords a very dull, yellowish shade of red, referred to as maroon. The pigment is considerably weaker than perylene pigments. All commercially available types of P.R.206 are more or less transparent and are used mostly in metallic finishes for automobiles, to which they lend reddish shades of copper. The pigment is often found to be difficult to disperse. The finishes frequently exhibit rheological problems, especially at high pigment concentration. 

Perylene and perinone pigments are chemically related. The group of perylene pigments is derived from perylene-3,4,9,10-tetracarboxylic acid 67, while perinone pigments are derivatives of napthalene-l,4,5,8-tetracarboxylic acid 68 ... 

The customary method of preparing perylene pigments is by reaction of perylene tetracarboxylic dianhydride with primary aliphatic or aromatic amines in a high boiling solvent. The dianhydride itself is also used as a pigment. Di-methylperylimide may also be obtained by treating the diimide with methyl chloride or dimethyl sulfate. 

Unsymmetrically substituted perylene pigments are a comparatively recent novelty. Selective protonation of the tetra sodium salt of perylene tetracarboxylic acid affords the monosodium salt of perylene tetracarboxylic monoanhydride in high yield. Stepwise reaction with amines produces unsymmetrically substituted perylene pigments [2],... 

Opaque perylene pigment varieties are treated in ball mills, either in the presence or absence of milling auxiliaries. The pigments are typically heated to 80 to 150°C in solvents such as methyl ethyl ketone, isobutanol, diethylene glycol, N-methylpyrrolidone, possibly in the presence of water. 

There are publications describing black perylene pigments [4], These compounds are chemically closely related to the corresponding red species, from which they are derived through slight changes in the substitution pattern on the moiety X which is not part of the conjugated system (see structure 74). 

The perylene pigment in which X= )N-CH2-CH2-0-CH2-CH3, for instance, affords a red shade, while X= )N-CH2-CH2-CH2-OCH3 produces a black shade. The difference in shade is attributed to a structurally controlled special arrangement of the pigment molecules within the crystal lattice. 

Representative commercial perylene pigments are listed in Table 29 Table 29 Commercially available perylene pigments. 

P.V.29 types demonstrate excellent weatherfastness, much more so than other perylene pigments. Their impact on the market, however, is limited by their very dull shade of maroon. Full shades are deep brown, almost black. The pigment is very fast to organic solvents and overcoating. Commercial types are utilized especially in metallic finishes. Full shades frequently bronze upon exposure to weather. 

The synthetic route to perinone pigments, as to perylene pigments, starts from an anhydride, in this case from the monoanhydride of naphthalene tetracarboxylic acid. 

Gregg et at.si) examined photosensitization of perylene pigments (Dye 15-17) on a porous Sn02 thin film instead of Ti02 film as DSC, in view of energy matching with conduction band of semiconductors and LUMO of the sensitizers. When perylene-3,4-dicarboxylic acid-9,10-(5-phenanthroline) carboximide (Dye 15) was used, Jsc of 3.26 mA-cm 2, of 0.45 V, and a photoelectric conversion efficiency of 0.89% were observed under AM 1.5 irradiation. IPCE achieves close to 40% at 460 nm. 

Langhals, H. Wetzel, F. Perylene Pigments with Metallic Effects. Ger. Offen. DE 10357978.8, Dec 11,2003 Chem. Abstr. 2005, 143, 134834. 

Perhaps the most widely used of the perylene pigments is Pigment Red 179 8-n (X = N-CHs), also known as perylene red. In spite of the intensive investigation and widespread use of this compound, it can join the ranks of sucrose and naphthalene as very commonly crystallized compounds that as yet have exhibited no evidence of polymorphism. 

Imahori, S. and Hirako, S. (1976). jS-crystalline phase perylene pigment— prepn by condensing with xylidine derived in organic solvent. Mitsubishi Chemical Industries Co. Ltd. Patent JP 51-7025 Chem. Abstr, 84, 16625D. [261t]... 

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