Paper Sulfur Dyes

Phthalocyanine Dyes. In addition to their use as pigments, the phthalocyanines have found widespread appHcation as dyestuffs, eg, direct and reactive dyes, water-soluble dyes with physical or chemical binding, solvent-soluble dyes with physical or chemical binding, a2o reactive dyes, a2o nonreactive dyes, sulfur dyes, and wet dyes. The first phthalocyanine dyes were used in the early 1930s to dye textiles like cotton (qv). The water-soluble forms Hke sodium salts of copper phthalocyanine disulfonic acid. Direct Blue 86 [1330-38-7] (Cl 74180), Direct Blue 87 [1330-39-8] (Cl 74200), Acid Blue 249 [36485-85-5] (Cl 74220), and their derivatives are used to dye natural and synthetic textiles (qv), paper, and leather (qv). The sodium salt of cobalt phthalocyanine, ie. Vat Blue 29 [1328-50-3] (Cl 74140) is mostly appHed to ceUulose fibers (qv). 

Sulfur dyes are used mainly for dyeing textile ceUulosic materials or blends of ceUulosic fibers (qv) with synthetic fibers such as acryUc fibers, polyamides (nylons), and polyesters. They are also used for sHk (qv) and paper (qv) in limited quantities for specific appHcations. Solubilized sulfur dyes are used on certain types of leathers (qv). 

Used industrially for dehairing hides, wool pulling, ore flotation, metal refining, engraving, cotton printing, in the manufacture of paper, pharmaceuticals, rubber, and sulfur dyes. It is used in production of heavy water for nuclear reactors. 

Sulfur dyes of the Indocarbon type (C.I. Sulphur Black 6, 53295 [1327-16-8], C.I. Sulphur Black 7, 53300 [1327-17-9] and C.I. Sulphur Black 11, 53290 [1327-14-6]) are also used for printing on these fibers. Sulfur dyes find limited use with polyamide fibers, silk, leather, paper, and wood. 

Numerous cationic azo dyes are prepared by the action of /V-hydroxymcthyl-chloroacetamide on azo dyes in sulfuric acid medium, followed by displacement of the reactive chloro substituent by pyridine or trialkylamine. Of special significance for dyeing paper are dyes that are prepared by coupling of diazotized 2-(4 -aminophenyl)-5-methylbenzothiazole to acetoacetaiylides, pyrazolones, naphthols [143], or barbituric acid derivatives [144], followed by reaction with N-hydroxymethylchloro-acetamide and pyridine. The azo dye obtained by oxidative dimerization of 2-(4 -aminophenyl)-5-methylbenzothiazole may also be subjected to this conversion [145], Dye 51 colors paper yellow. 

Basic dyes are used almost exclusively for overdyeing, e g., to achieve deep black shades by laking. Recent research indicates that new cationized sulfur dyes for leather will shortly become commercial products. In the 1970s dicationic azo dyes for paper were introduced by azo coupling of aromatic diazonium ions with heterocylic components. The resulting cationic azo dyes are also applied on leather e.g. C.I. Basic Black 11. The constitution is not disclosed. 

Sulfur dyes are water-insoluble, macromolecular, colored compounds which are produced by bridging aromatic amines, phenols, and amino phenols with sulfur and/or sodium polysulfide [16], These dyes are of little interest for dyeing paper. Only C.I. Sulphur Black 1 (36), the most important dye of all in terms of volume, is used for special paper dyeings. 

P2S5, putty, gunpowder, sulfur dyes, sulfur concrete, paper... 

Sulfuric acid is the most commonly produced industrial chemical in the world. More than 37 million metric tons of it are made each year in the United States alone. Sulfuric acid is used in large quantities in petroleum refining and metallurgy as well as in the manufacture of fertilizer. It is also essential to a vast number of industrial processes, including the production of metals, paper, paint, dyes, detergents, and many chemical raw materials. Sulfuric acid is the acid used in automobile batteries. 

The practical route for oxidizing leuco diphenylmethanes 15 demands inital conversion to an imine salt 16. The imine salt is obtained by heating a mixture of diphenylmethane, sulfur, ammonium chloride, and sodium chloride at 175°C in a current of ammonia or by heating a mixture of diphenylmethane, urea, sulfamic acid, sulfur, and ammonia at 175°C (Scheme 3). Dyes 16 can be represented as the quinonoid resonance structure 17. Dyes of this class, known as auramines, are all yellow, with the only commercial representative being auramine O 16a. Due to its poor lightfastness and instability to hot acids and bases, its use has been restricted to dyeing and printing cotton, paper, silk, leather, and jute. 

It is first established whether the product is a single compound. This is done by dusting a small sample of the dye on moistened filter paper. A mixture can frequently be recognized from spots of different color. (Mixtures of water-insoluble dyes can often be detected by sprinkling a small sample onto concentrated sulfuric acid, advantageously placed in a depression in a white porcelain plate for the purpose.) Attempts are then made to purify the dye by reprecipitation until a pure material is obtained. Every effort is made to obtain the purest sample possible. This is a general rule for all dye analyses. 

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