Лако-красочные материалы — производство

A number of methods of synthesis of the quinacridones are reported. Each of these involves several stages, accounting at least in part for the somewhat higher cost of these pigments. The two most important routes to the parent compound are outlined in Scheme 4.9. In both cases, the starting material, diethyl succinylsuccinate (84, 1 mol), […]

Indigo (57) was for many centuries obtained from natural sources. The chemical structure of indigo was first proposed by von Baeyer in 1869, and eleven years later he reported the first successful synthesis, a multi­stage route starting from o-nitrocinnamic acid. The first successful com­mercial synthesis of indigo, attributed to Heumann in 1897, is shown in […]

The synthesis of anthraquinone colorants may effectively be envisaged as involving two stages. The first stage involves the construction of the anthraquinone ring system and in the second phase the anthraquinone nucleus is elaborated to produce the desired structure. Frequently the latter involves substitution reactions, but group interconversion and further cyclisation reactions may also be […]

The synthesis of carbonyl colorants uses a wide diversity of chemical methods, in which each individual product essentially has its own charac­teristic route. This is in complete contrast to the synthesis of azo dyes and pigments (Chapter 3) where a common reaction sequence is universally used. The subject is too vast to attempt to be […]

The quinone-hydroquinone system represents a classic example of a fast, reversible redox system. This type of reversible redox reaction is charac­teristic of many inorganic systems, such as the interchange between oxidation states in transition metal ions, but it is relatively uncommon in organic chemistry. The reduction of benzoquinone to hydroquinone reversible reaction involves the stepwise […]

There are a number of carbonyl colorant systems, which offer particular advantages as pigments for applications, such as automotive paints, which demand extremely high performance in terms of colouristics and fastness to light, heat and solvents. These carbonyl pigments are diverse structurally and include the quinacridones, diketopyrrolopyrroles, pery — lenes, perinones and anthraquinones and the […]

A number of carbonyl dyes are characterised by strong fluorescence. One of the most important groups of fluorescent brightening agents and dyes is based on the coumarin ring system. The important fluorescent coumarin derivatives almost invariably contain an electron-releasing substituent in the 7-position, which is most commonly a dialkylamino group but may be hydroxy or […]

The benzodifuranones constitute one of the more recently introduced groups of carbonyl dyes. They were launched commercially in the late 1980s by ICI as disperse dyes for application to polyester. This group of dyes, of which compound 62 is a representative example, are capable of providing a range of colours but the most important are […]

Indigo (57), the parent system of this group of colorants, is one of the oldest known natural dyes (see Chapter 1). The naturally occurring material is indican, the colourless glucoside of indoxyl. When subjected to a fermentation process, free indoxyl (58) is generated by enzymic hydroly­sis and this compound undergoes oxidation in air to indigo. […]

A common arrangement of the carbonyl groups in coloured molecules gives rise to a group of compounds known as quinones. These may be defined as cyclohexadienediones, i. e. compounds containing two ketone carbonyl groups and two double bonds in a six-membered ring. The simplest quinones are o — and p-benzoquinones, 49 and 50 respectively. Derivatives […]