Dyes and Colorants

Principal uses of KOH include chemicals, particularly the production of potassium carbonate and potassium permanganate, pesticides (qv), fertilizers (qv), and other agricultural products soaps and detergents scmbbing and cleaning operations, eg, industrial gases dyes and colorants and mbber chemicals (qv) (10,34). 

Reduction of the azo group in dyes and colorants is the key reaction in their decolorization. Although an azo reductase mediates the reduction of azo groups to amines, the metabolic situation is quite complex. The enzyme is apparently synthesized under both aerobic (Bliimel et al. 2002) and... 

Societe Anonyme de Matieres Colorantes et Produits Chimiques," the combine was called "Francolor" for short, so as to suggest only the manufacture and sales of dyes and "colors."... 

Potassium hydroxide is used to make soft soap, in scrubbing and cleaning operations, as a mordant for woods, in dyes and colorants, and for absorbing carbon dioxide. Other principle uses of caustic potash are in the preparation of several potassium salts, acid-base titrations, and in orgainic sytheses. Also, KOH is an electrolyte in certain alkaline storage batteries and fuel cells. 

J.R. Aspland, Textile Dyeing and Coloration, American Association of Textile Chemists and Colorists, NC, 1997. 

Azo or diazene compounds possess the —N=N— grouping. Aliphatic azo compounds of the type R—N=N—H appear to be highly unstable and decompose to R—H and nitrogen. Derivatives of the type R—N=N—R are much more stable and can be prepared as mentioned above by oxidation of the corresponding hydrazines. Aromatic azo compounds are available in considerable profusion from diazo coupling reactions (Section 23-IOC) and are of commercial importance as dyes and coloring materials. 

On the other hand, many excipients can act to chemically stabilize an API in the solid state and in solid dosage forms. The most common class of stabilizing excipients is cyclodextrins (36). Cyclodextrins can envelop the API in their hydrophobic cavities and shield it from common degradation reactions such as hydrolysis, oxidation, or photodegradation. Some excipients or additives may also act as complexing agents that provide hydrolytic (37) and oxidative (38) stabilization. Many excipients, such as cyclodextrins, dyes, and colored additives, are capable of providing extensive photostabilization in the solid state (39-41). 

Dyes and color pigments Leather tanning and leather processing Rayon and synthetic hber manufacturing Sodium/potassium cyanide-associated industries Basic drugs manufacturing Foundry industries Storage batteries (lead acid type)... 

Depilatories, dressings, dyes and colors, grooming aids, lighteners, miscellaneous rinses, permanent waveproducts, shampoos, sprays, straighteners, tints, tonics, wave sets... 

An adsorption indicator is typically an organic dye, such as fluorescein and its derivatives. Most adsorption indicators are weak acids. Their use is thus confined to basic, neutral, or slightly acidic solutions in which the indicator exists predominantly as the anion. Some cationic adsorption indicators are suitable for titrations in strongly acidic solutions. In this case, adsorption of the dye and coloration of the precipitate occur if the precipitate particles possess a negative charge. 

Dimethylaminoazobenzene was once used as a coloring agent for butter and margarine. Dimethylaminoazobenzene was also used as an intermediate in the production of dyes, photosensitive polymers, and reusable films. Dimethylaminoazobenzene is no longer used as a dye and coloring agent. 

Use Dye and color intermediate, pharmaceuticals, cinnamic acid, soaps, photography, purification of glucose, meat preservation, medicine, electroplating, tanning, dehydrating agent, buffer, lab reagent, food additive. 

Use Manufacture of sulfur dyes and colors, insecticides, oil-resistant synthetic rubber ( Thiokol ), petroleum additives, electroplating. 

Dye-Based Systems Many compounds can be used [lh,i]. Classical examples are found in the numerous available dyes and colored molecules [li] such as xanthenic dyes (Rose Bengal, eosin [194,195], etc.), thiazines (methylene blue, etc.), acridines, /V-methylacridone, phenosaffanines, thiopyronines, riboflavines [196,197], pheno-xazines [198], pyrromethenes [199], polymethines, fluorones, squarylium [200], julolidine dyes, and so on. (see, for example, Rose Bengal, acriflavine, and acridine orange in (10.57)). 

In the manufacture of various types of dyes and coloring agents ... 

Products and Uses A dye and coloring agent in red ink, cosmetic products, lipstick, nail polish, and motor fuel coloring. 

In addition to introducing chemical changes in polymers, light also causes dyes and colorants to fade (Figure 6.11). 

Uses Mfg. of sulfur dyes and colors, insecticides, oil-resist, syn. mbber, petroleum additives electroplating in food-contact polysulfide polymer/polyepoxy resins in food-contact mbber articles for repeated use Regulatory FDA 21 CFR 177.1650, 177.2600 Manuf./Distrib. Expo Chem. http //www.expochem.com Los Angeles Chem. Tessenderlo Kerley See also Sodium sulfide... 

The reaction mixture used in this procedure may find application in freezing mixtures because of its high negative heat of reaction. Barium thiocyanate has been used in the dye and color printing industries and as a dispersing agent for cellulose. It can be converted readily by treatment with a dilute sulfuric acid to give dilute solutions of thio-cyanic acid, or into the thiocyanates of other metals by precipitation of barium sulfate. 

Amaplast, High-paTamance dyes and colorants, Color-Chem International Corp. 

Dyes and colorants are complex organic molecules with conjugated or delocalized iT-electron systems (chromophores). Based on the different relevant chemical functionalities that act as chromophores in specific dyes, the latter can be grouped into azo dyes, carbonyl dyes, methine dyes, and phthalocyanines. The dye indigo shown in Table 5.3.19 belongs to the group of carbonyl dyes. 

Naphthol is also used in the synthesis of dyes and colorants. It is used in the synthesis of fungicides, antiseptics, and pharmaceuticals. 

---