Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Quinacridone pigment

Yet other processes have used sulphuryl chloride (S02C12), thionyl chloride (SOCl2) or sulphur dichloride (SC12) as chlorinating agents. [Pg.71]

The synthesis of linear turns-quinacridone (2.38) was reported in 1935 by Liebermann [26] and was cursorily looked at as a red vat colorant but not developed commercially. It was more than twenty years later that the DuPont company introduced these compounds as pigments under the trade name of Cinquasia. Their chemical structures are based on Cl Pigment Violet 19 (2.38). As with the phthalocyanines, this compound can exist in several polymorphic forms in this case there are three, termed a-, p- and y- forms only the last two being useful as pigments. The first three pigments were called Cinquasia Red B (y-form, size above 1000 nm), Cinquasia Red Y (y-form, size below 1000 nm) and Cinquasia Violet R (P-form). [Pg.71]

Quite apart from the problems of chemical synthesis, it is clear that the application of physico-chemical methods to pigment manufacture, first needed in the development of the [Pg.71]

The chemical synthesis of linear turns-quinacridones and their substituted derivatives that have been marketed subsequently is a complicated multi-stage sequence, making such pigments very expensive and sustainable only where high-fastness red pigments are essential, as in the car industry. There are four routes of synthesis, details of which have been given by Pollack [27]. [Pg.72]

The DuPont company used the succinic acid ester process, in which diethyl succinate is first cyclised to diethyl succinylsuccinate (2.39) in a sodium/alcohol mixture. One mole of the product is next condensed with two moles of aniline under oxidising conditions, forming diethyl 2,5-dianilino-3,6-dihydroterephthalate (2.40). Ring closure at 250 °C gives dihydroquinacridone, from which quinacridone is obtained by oxidising away the two extra hydrogen atoms. [Pg.72]

Terence R. Chamberlain (modification of original chapter by Edward E. Jaffe) [Pg.293]

High Performance Pigments. Edited by Edwin B. Faulkner and Russell J. Schwartz Copyright 2009 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31405-8 [Pg.293]

The isomeric linear ds-quinacridone, or isoquinacridone 6, was synthesized in 1921 [6] and the linear trans-quinacridone 2, quino[3,2-b]acridine-5,12-dihydro-7,14-dione was synthesized by an unambiguous route, by Liebermann and coworkers [7], Berlin 1935. [Pg.294]

The red-violet compound attracted no particular attention until 1955 when chemists at DuPont discovered two attractive syntheses, demonstrated its photochemical stability, and identified three polymorphic forms each with distinct structural characteristics. In addition, methods were developed for the preparation of quinacridone in useful pigmentary forms. The first pigments were commercialized in 1958. [Pg.294]


An important use of dialkyl succinates is in the preparation of dialkyl succinyl succinates (35,53—56), which are intermediates in the manufacture of quinacridone pigments. The reaction is carried out in the presence of alkaU metal alkoxides (eq. 2). [Pg.535]

Quinacridone Pigments. The quinactidones have the following formula ... [Pg.462]

Quaternary ammonium compounds biocidal activity mechanism, 1, 401 toxicity, 1, 124 Quaternization heterocyclic compounds reviews, 1, 73 ( )-Quebrach amine synthesis, 1, 490 Queen substance synthesis, 1, 439 4, 777 Quercetin occurrence, 3, 878 pentamethyl ether photolysis, 3, 696 photooxidation, 3, 695 Quercetrin hydrolysis, 3, 878 Quinacetol sulfate as fungicide, 2, 514 Quinacridone, 2,9-dimethyl-, 1, 336 Quinacridone pigments, 1, 335-336 Quinacrine... [Pg.826]

In the manufacture of quinacridone pigments only the first and last of the four routes outlined have been operated commercially. Synthesis is followed by the milling processes necessary to give products with the crystal structure and particle size required for their use as pigments. [Pg.73]

Particularly large color changes are associated with the transition from solution to solid state in heterocycles such as the cross-conjugated indigo system or the quinacridone skeleton. Quinacridone pigments, dissolved in concentrated sulfuric acid or in DMF, exhibit a pale yellow shade the intense red color appears only in the solid state. This is a particularly distinctive example to demonstrate the correlation between crystal lattice interactions and hue [9]. [Pg.15]

Lightfastness and weatherfastness of quinacridone pigments (Sec. 3.2) deteriorate in the order 2,9 - 3,10 - 4,11 substitution. It is assumed that decreasing the distance between substituents and NH function disturbs the formation of hydrogen bonds [14] a tendency which culminates in the very poor light and weather resistance of 5,12-N,N -dimethyl quinacridone. [Pg.21]

Another phenomenon to be detected by X-ray crystallography is the formation of mixed crystals, as observed in the mixed coupling of azo pigments or the solid solutions of quinacridone pigments. A change in the angles of the reflected X-rays of a mixed crystal indicates a transition from one crystal phase to another. If, how-... [Pg.44]

To obtain the necessary fastness properties, high-quality pigments are generally used for security printing. The range of suitable products covers disazo, disazo condensation, benzimidazolone, naphthol AS, isoindolin, perinone, anthanthrone, dioxazine and quinacridone pigments. [Pg.153]

A few years ago the pigment was withdrawn from the market. P.R.212 was rarely sold outside Japan. It produces considerably bluish shades of red, which might be considered pink. Compared to the similarly colored quinacridone pigment P.R.122, P.R.212 is duller, weaker, and less fast. 1/3 SD letterpress proof prints, for instance, equal step 2-3 on the Blue Scale for lightfastness while prints containing P.R.122 equal step 6-7. P.R.212 is also less lightfast than the somewhat more bluish and duller benzimidazolone pigment P.V.32, a coloristically related maroon the difference is 2 to 3 steps on the Blue Scale. [Pg.308]

Most pigments derived from vat dyes are structurally based on anthraquinone derivatives such as indanthrone, flavanthrone, pyranthrone, or dibromoan-thanthrone. There are other polycyclic pigments which may be used directly in the form in which they are manufactured. This includes derivatives of naphthalene and perylene tetracarboxylic acid, dioxazine (Carbazole Violet), and tetrachloro-thioindigo. Quinacridone pigments, which were first introduced in 1958, and recently DPP pigments have been added to the series. [Pg.421]

Some 20 years later, W.S. Struve (1955) at Du Pont was the first to recognize the impact of linear quinacridone on the pigment industry. In due course, the first industrially useful synthetic pathway was found. Three commercial types of unsubstituted quinacridone consisting of two crystal modifications were introduced in 1958 [3]. From then on, quinacridone pigments have been one of the most recent classes of pigments to experience rapid development, especially throughout the USA and Western Europe. [Pg.453]

Several synthetic pathways for the commercial manufacture of quinacridone pigments have been published. In this context, only those routes are mentioned which were developed for industrial scale production. There are four options, the first two of which are preferred by the pigment industry. It is surprising to note that these are the methods which involve total synthesis of the central aromatic ring. On the other hand, routes which start from ready-made aromatic systems and thus might be expected to he more important actually enjoy only limited recognition. [Pg.453]

Oxidation of dihydroquinacridone to quinacridone may be achieved, for instance, with the sodium salt of m-nitrobenzene sulfonic acid in aqueous ethanol in the presence of sodium hydroxide solution [7]. A distinction is made between heterogeneous and homogeneous oxidation. The reaction is referred to as a solid state oxidation if the solvent contains approximately 2% sodium hydroxide solution. A content of approximately 30% sodium hydroxide solution relative to the solvent mixture, on the other hand, converts the reaction into a so-called solution oxidation . The type of ring closure defines the crystal modification of the resulting dihydroquinacridone, while the oxidation technique defines the crystal phase of the quinacridone pigment. [Pg.455]

Solid state oxidation, both of the a- and the 3-phase [8] of dihydroquinacridone, affords crude a-quinacridone. Subsequent milling with salt in the presence of dimethylformamide produces the 7-modification, while the 3-form evolves in the presence of xylene. Solution oxidation of dihydroquinacridone, possibly performed as air oxidation in the presence of 2-chloroanthraquinone [9], forms crude 3-quinacridone. Milling with xylene likewise affords 3-quinacridone pigment (see tables of chemical structures on p. 613). [Pg.455]

The (3-crystal modification is prepared by pretreating the crude quinacridone product with alkali base before finishing with the solvent. Immediate solvent treatment, on the other hand, produces the 7-modification of the quinacridone pigment. [Pg.456]

All industrially significant quinacridone pigments are deeply colored products. They cover the spectral range from yellowish red to violet shades. Quinacridone pigments do not melt but decompose at high temperature. [Pg.461]

The exact cystal structure of quinacridone pigments has been published recently. So far, models indicated a planar arrangement of the molecules within the crystal lattice [21], In fact, it was now been proved recently by three-dimensional X-ray analysis that the pigment exists in two different crystal modifications [22] ... [Pg.461]


See other pages where Quinacridone pigment is mentioned: [Pg.836]    [Pg.21]    [Pg.31]    [Pg.31]    [Pg.31]    [Pg.539]    [Pg.724]    [Pg.80]    [Pg.80]    [Pg.794]    [Pg.8]    [Pg.53]    [Pg.71]    [Pg.71]    [Pg.8]    [Pg.8]    [Pg.41]    [Pg.76]    [Pg.304]    [Pg.339]    [Pg.359]    [Pg.400]    [Pg.400]    [Pg.452]    [Pg.452]    [Pg.452]    [Pg.454]    [Pg.456]    [Pg.458]    [Pg.460]    [Pg.461]    [Pg.461]   
See also in sourсe #XX -- [ Pg.79 , Pg.80 , Pg.90 , Pg.164 ]

See also in sourсe #XX -- [ Pg.8 , Pg.452 ]

See also in sourсe #XX -- [ Pg.120 , Pg.146 , Pg.151 , Pg.181 ]

See also in sourсe #XX -- [ Pg.108 ]

See also in sourсe #XX -- [ Pg.18 ]

See also in sourсe #XX -- [ Pg.190 , Pg.290 ]

See also in sourсe #XX -- [ Pg.112 , Pg.113 , Pg.114 , Pg.115 , Pg.126 , Pg.127 ]

See also in sourсe #XX -- [ Pg.496 ]

See also in sourсe #XX -- [ Pg.110 , Pg.132 , Pg.293 , Pg.424 ]




SEARCH



Coatings quinacridone pigments

Commercially Available Quinacridone Pigments

High quinacridone pigments

Organic pigments quinacridones

Plastics quinacridone pigments

Quinacridone quinone pigments

Quinacridones

Visible Spectra of Quinacridone Pigments

Visible quinacridone pigments

© 2024 chempedia.info