Лако-красочные материалы — производство

Indigo is the most important vat dye, dating back to ancient times and produced on an industrial scale since 1880. To replace the indigo dyes, the indanthrone (21) class of dyes was developed. Indanthrone has superior characteristics as a vat dye and became a key material for further develop­ment of anthraquinoid vat dyes. There exist […]

Anthraquinone leuco dyes are widely known as vat dyes.10 Vat dyes possess extensively conjugated aromatic systems containing two or more carbonyl groups, e. g., anthraquinone, indigoid chromophores. The colored form of vat dyes are insoluble in water. The dyes are applied by a process whereby the dye is converted to the reduced form (leuco dye) […]

In 1963, Bloom and Hutton suggested5 the structure of leuco quinizarin in solution as 9,10-dihydroxy-2,3-dihydro-1,4-anthraquinone (9a). In 1981, Kikuchi and colleagues6 confirmed the structure by means of 1H — and 13C-NMR. The structures of the leuco derivatives of 1,4-bis(butylamino)- anthraquinone (14) and 1-butylamino-4-hydroxyanthraquinone (15) have been shown to be 1,4-bis(butylamino)-2,3-dihydroanthracene-9,10-dione (16a) and 1-butylamino-10-hydroxy-2,3-dihydroanthracene-4,9-dione (17a), respectively. […]

In the past, various leuco benzoquinone dyes4 were used as mordant dyes but recently they have been displaced by the azo mordant dyes. The reaction of p-benzoquinone with p-chloroaniline gives the hydroquinone derivative (5). Compound 5 undergoes oxidation to the corresponding benzoquinone 6. A mixture of hydrosulfite and compound 6 is marketed as a sulfurized […]

The most valuable colorless naturally occurring hydroquinone is hema­toxylin (1)3 which is extracted from logwood, native to Central America. Compound 1 absorbs at 298nm in methanol but is rapidly oxidized by atmospheric oxygen and converts to hematein (2) which contains a para — quinoidal chromophore. Compound 1 is white in the pure state, turning yellow […]

MASARU MATSUOKA 2.1. INTRODUCTION The chemistry of quinone dyes has been discussed in a series of books entitled The Chemistry of Synthetic Dyes, edited by Venkataraman.1 The general chemistry of quinoid compounds has been discussed by Patai.2 There have been many books that cover quinoid compounds as dyes and pigments but very few discuss the […]

Due to the absorption band of the colored form of spiroindolinoben- zothiopyrans in the near IR region, they have been used in the optical erasable recording disks.89,100,101 The principle of optical erasable record­ing system using photochromic spirobenzothiopyran is explained as follows. First, the recording layer which contains photochromic spiroben­zothiopyran in liquid-crystal polymer or polymer such […]

Though the colored form of unsubstituted spirobenzothiopyran is unstable, the nitrosubstituent leads to stabilization of the colored form. The absorption maxima of some 6-nitrospiroindolinobenzothiopyrans 44 in a Table 7. Absorption Maxima of the Colored Form of Spiroindolinobenzothiopyran 44 in Vinyl Chloride-Vinylidene Chloride Copolymer R1 R2 ^ max, nm H 6-NO2 680 C1 6-NO2 690 no2 […]

Spiroindolinobenzothiopyrans can be prepared by condensation of Fischer’s base with thiosalicylaldehyde derivatives 46 in ethanol, as shown in Scheme 22.71,89’93 Reaction of 1,2,3,3-tetramethylindolinium salt with carbamoylthiobenzaldehyde,92 which is an intermediate for preparation of thiosalicylaldehyde, also gives the spirobenzothiopyran in high yield via the corresponding indolinium salt, as shown in Scheme 22.94 Conversion of spirobenzopyrans to […]

1.4.1. Molecular Design for the Near-IR Dyes Becker and Kolc first examined the photochromism of spiroindo- linobenzothiopyran 44, a thio analogue of spiroindolinobenzopyran (Scheme 19). The closed form of this spirobenzothiopyran is stable and the photocoloration is very slow, compared with spiropyrans.71 In recent years, much effort has been focused on the development of new […]