Лако-красочные материалы — производство

Only one report45 of monoarylmethane color formers has appeared to date, the synthetic route being shown in Scheme 6. These compounds in combination with clay developers give yellow images with good light stability.

In order that diarylmethane phthalides function as color formers, it is necessary to replace the hydrogen atom in the 3-position of the phthalide ring by an electronegative group. Scheme 5 typifies the synthetic route to such phthalides. Once again the key intermediate is the carboxyben — zophenone which, on treatment with acetic anhydride, yields the […]

4.2.1. Triarylmethane Phthalides Since the introduction of carbonless copying papers, CVL has un­doubtedly found the most widespread use as a phthalide color former. Hence, it is appropriate to describe in detail the various approaches to its synthesis, particularly as they are representative of the preparations of various other phthalides described herein. (CH3)2n The first synthesis […]

IAN J. FLETCHER and RUDOLF ZINK 4.1. INTRODUCTION Considering the fact that 3,3-bis(4-dimethylaminophenyl)phthalide (1), commonly known as Malachite Green lactone, was reported1 well over 100 years ago, it is somewhat surprising to realize that the analogous 6- dimethylaminophthalide [Crystal Violet lactone (CVL)] (2) was not de­scribed until 1945,2 and that the vast majority of references […]

Dye release developers are themselves colored molecules, the presence of which in silver halide photographic materials could interfere with light capture by the light-sensitive silver halide. Less light would be available to the sensitizing dyes. Another approach has been reported in which the leuco dye is linked to the coupling-off position of conventional photographic color […]

Leuco Methylene Blue, Basic Blue 3, or phenazine dyes are capped with a dye bearing acid chloride or chlorocarbonyl functionality. Normal procedures employed for the synthesis of benzoyl leuco Methylene Blue can be utilized except that a dye chloroformate (69) replaces the benzoyl chloride. The exocyclic amino group of Azures A or B can be […]

3.5.1. Introduction The leuco dyes of this new class are peculiar in that they are capped at their 10-position by another dye moiety. They are in fact colored leuco dyes which on oxidation are split into two different dye fragments: one of the dyes is destined for the receptor sheet while the oxidized leuco hopefully […]

Phenazine leuco dyes, like their thiazine and oxazine analogues, have also found application in electrolytic recording, overhead transparencies, and Color Dry Silver. The phenazine leuco 48 is employed in electrolytic recording,17 whereas compounds 49, 50 are described as useful in thermo­graphic and photothermographic systems. 18 Phenazine leucos are generally more reactive and more susceptible to […]

The availability of oxazine leucos is dictated by the ease of synthesis of the oxazine dyes. The purple phenoxazone 36 is obtained by alkaline hydrolysis of Basic Blue 3.14 The benzophenoxazone 38 is obtained by coupling of 2-nitroso-5- diethylaminophenol with a-naphthol.14 The leucos 37 and 34 are obtained by refluxing the corresponding dyes with zinc […]

Examples of nonacylated oxazine leucos are rare, possibly due to the high cost of the phenoxazine starting material. Apart from a few examples described earlier, the leuco 35 is reported to give a blue image.8