Solvent dye

Solvent dyes are really intermediate between dyes and pigments being insoluble in water but soluble in solvents, especially hydrocarbons. Structurally many solvent dyes bear a close similarity and relationship with disperse dyes. The Colour Index has an issne on Solvent Dyes, where several hundred dyes are described, unfortunately many of the strnctnres remain confldential. The structures of the disclosed dyes range from very simple monoazo dyes, e.g. Cl Solvent Yellow 14 (2.78) to the higher performing anthraquinones, e.g. Cl Solvent Yellow 163 (2.79) and Blue 36 (2.80), quinophthalones 

Because of their high solubility in hydrocarbons they have found a widespread use as markers for the identification of the various fractions of hydrocarbons that are produced in oil refineries. For instance, red and blue diesels (see also 1.6.2.1). Although used only in very low quantities the vast amount of fuels used in the world means that solvent dyes are manufactured on a very large scale. 

Several solvent dyes show very high performance in plastics and are used widely in the coloration of thermoplastics and engineering resins, e.g. PC and ABS. 

Solvent dyes are also used in the coloration of any solvent or wax based product, including polishes, cosmetics, crayons, candles, inks, stains and adhesives. They are also in the coloured smokes that are used in outdoor displays, for instance coloured trails from aircraft, and in safety and security applications. 

Because several solvent dyes are fluorescent they are used in the production of fluorescent dyes and pigments for a variety of outlets, as described in Chapter 3 (sections 3.5.1 and 3.5.2). 

Solvent Dves Solvent dyes often resemble dyes in other classes, except that these dyes contain groups that improve their solubility in solvents such as alcohols and chlorinated hydrocarbons. It is often possible with solvent dyes to dye certain fibers which would be poorly dyeable fiom aqueous solution. 

Another reactive component for leather (major use dyeing wool) is thea-sul-fatoethylsulfonyl group, as in e.g., C.l. Reactive Violet 4, 17965 [12769-08-3] (1 1 Copper 21), as well as acryloamido, e.g., a-bromoacryloamido groups. 

On leather, reactive dyes attach to the amino group of lysine and hydroxyly-sine moieties of collagen. A tanning effect may occur if one reactive group reacts with leather. However, the reaction of the electrophilic group of reactive dyes with water (hydrolysis) competes with the fixation reaction of forming a covalent bond between the dye and the substrate. The hydrolyzed dye cannot react with the fiber. Leather absorbs the noncovalently bound dye like a conventional anionic dye. Unlike on textiles, these hydrolyzed dyes cannot be easily washed off. That is the reason why sometimes no decisive wetfastness improvement can be achieved. 

Commercial solvent dyes for leather are employed in a great variety of solvents. It is common practice to use mixed solvents to obtain the requisite physical properties. They are also applied to correct off-shade dyeings and improve the brilliance of shades. Alcohols or glycols are the most common solvents but esters and ketones are also convenient. The colors are normally applied to dyed or undyed tanned leather by spraying from solvent solution or aqueous/organic emulsions. Nowadays, water-based finish recipes, which are combinations of sol- 

The features of chemical constitution associated with the special requirement of solvent solubility include a number of chemical groups on the chromophores. Sulfo groups are often absent, and only hydroxy or amine groups are present. There are mostly cationic and neutral and sometimes also anionic azo, 1 2 azo metal-complex, and a few anthraquinone dyes. An example is C.I. Solvent Yellow 21, 18690 [5601-29-6] (22, 1 2 Chrome alsoC.7. Acid Yellow 121). 

The dyes should not contain any inorganic byproducts or diluents. The preferred anionic dyes include salts formed by using ammonia as cation, or special tetraalkylamines, e.g., C.I. Solvent Orange49, (Orange II see Section 5.3) with an amine condensate as cation. 

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SolventBlue 56 Solvent coating Solvent cook Solvent dyeing Solvent dyes... 

Most xanthene dyes are classified as basic dyes by their method of appHcation acid dyes can be produced by introduction of sulfonic acid groups. The fluoresceins, which contain carboxy and hydroxy substituents, are also acid dyes for coloration of silk. Some of the fluoresceins in which the carboxy group has been esterified, are soluble in alcohol or other organic solvents and can be classified as solvent dyes. Mordant dyes can be produced by introducing o-dihydroxy or sahcyhc acid groups (2), which when metallised can have very good lightfastness. 

Dyes. Dyes are added to gasoline to impart color for a number of reasons. Originally, these compounds were used to identify leaded gasoline so that it would not be used for other inappropriate purposes, such as solvents. Dyes are used to identify different gasoline grades so that pipeline companies can separate tenders, and so that service stations can easily check that the correct grade was placed in the underground tanks (aq). Dyes are usually based on a2o chemistry and are added in concentrations below 10 ppm (see Azo dyes). 

Dyes, Dye Intermediates, and Naphthalene. Several thousand different synthetic dyes are known, having a total worldwide consumption of 298 million kg/yr (see Dyes AND dye intermediates). Many dyes contain some form of sulfonate as —SO H, —SO Na, or —SO2NH2. Acid dyes, solvent dyes, basic dyes, disperse dyes, fiber-reactive dyes, and vat dyes can have one or more sulfonic acid groups incorporated into their molecular stmcture. The raw materials used for the manufacture of dyes are mainly aromatic hydrocarbons (67—74) and include ben2ene, toluene, naphthalene, anthracene, pyrene, phenol (qv), pyridine, and carba2ole. Anthraquinone sulfonic acid is an important dye intermediate and is prepared by sulfonation of anthraquinone using sulfur trioxide and sulfuric acid. 

Solvent Dyes. These water-iasoluble dyes ate devoid of polar solubilizing groups such as sulfonic acid, catboxyHc acid, or quaternary ammonium. They ate used for coloring plastics, gasoline, oUs, and waxes. The dyes ate ptedomiaandy azo and anthraquiaone, but phthalocyaniaes and ttiaryHnethane dyes ate also used. 

A Methylanthrapyridone and Its Derivatives. 6-Bromo-3-methylanthrapyridone [81-85-6] (75) is an important iatermediate for manufacturiag dyes soluble ia organic solvents. These solvent dyes are prepared by replacing the bromine atom with various kiads of aromatic amines. 6-Bromo-3-methylanthrapyridone is prepared from 1-methyl amino-4-bromoanthra quin one (43) by acetylation with acetic anhydride followed by ring closure ia alkaU. The startiag material of this route is anthraquiaoae-l-sulfonic acid (16). 

Solvent Dyeing. Solvent dyeing generaUy refers to dyeing in nonaqueous media. In the early 1970s, solvent dyeing was expected to become the dyeiag process of the future and was discussed and researched extensively (32). This interest did not materialize into practical acceptance and the technique has not achieved importance. 

Sodium, K, Ca, Mg, Zn and Fe and inorganic chlorides are the most widely occurring contaminants in solvent dyes for engineering thermoplastics such as PC, and need to be contained to within 250 ppm (specification ICP verification for QC purposes) [202]. 

Chapter 2 Organic and inorganic pigments solvent dyes... 

Solvent dewaxing, 13 662, 670 Solvent dyeing, 9 160, 204, 243 Solvent effects, 23 96... 

Colour Index International, Pigments and solvent dyes Edn (Bradford SDC 1998). 

Textile dyes can be dissolved or solubilised in water to a greater or lesser extent, this being essential for all conventional dyeing processes. Since solubility in water is generally accompanied by insolubility in nonpolar solvents, most textile dyes have this property. Solvent dyes, on the other hand, are soluble in organic solvents but insoluble in water. Solvent dyes are used as colour markers for the many different hydrocarbon fractions produced in oil refineries. Although the concentration of dye is low, the vast volumes involved makes the overall dye usage considerable. 

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