Rayon, synthesis

Three forms of caustic soda are produced to meet customer needs purified diaphragm caustic (50% Rayon grade), 73% caustic, and anhydrous caustic. Regular 50% caustic from the diaphragm cell process is suitable for most appHcations and accounts for about 85% of the NaOH consumed in the United States. However, it caimot be used in operations such as the manufacture of rayon, the synthesis of alkyl aryl sulfonates, or the production of anhydrous caustic because of the presence of salt, sodium chlorate, and heavy metals. Membrane and mercury cell caustic, on the other hand, is of superior quaUty and... 

Until 1982, almost all methyl methacrylate produced woddwide was derived from the acetone cyanohydrin (C-3) process. In 1982, Nippon Shokubai Kagaku Kogyo Company introduced an isobutylene-based (C-4) process, which was quickly followed by Mitsubishi Rayon Company in 1983 (66). Japan Methacryhc Monomer Company, a joint venture of Nippon Shokubai and Sumitomo Chemical Company, introduced a C-4-based plant in 1984 (67). Isobutylene processes are less economically attractive in the United States where isobutylene finds use in the synthesis of methyl /i / butyl ether, a pollution-reducing gasoline additive. BASF began operation of an ethylene-based (C-2) plant in Ludwigshafen, Germany, in 1990, but favorable economics appear to be limited to conditions unique to that site. 

For rayon fiber based eomposites (Seetions 3 and 4) the fiber and powdered resins were mixed in a water slurry in approximately equal parts by mass. The isotropie piteh earbon fiber eomposites (Seetion 5) were manufaetured with less binder, typically a 4 1 mass ratio of fiber to binder being utilized. The slurry was transferred to a molding tank and the water drawn through a porous sereen under vacuum. In previous studies [2] it was established that a head of water must be maintained over the mold screen in order to prevent the formation of large voids, and thus to assure uniform properties. The fabrieation proeess allows the manufaeture of slab or tubular forms. In the latter case, the cylinders were molded over a perforated tubular mandrel covered with a fine mesh or screen. Moreover, it is possible to mold eontoured plates, and tubes, to near net shape via this synthesis route. 

Fi ire 8.7 Simplified flowsheet for viscose rayon production (from El-Halwagi and Srinivas, Synthesis of reactive mass-exchange networks, Chem. Eng. Set., 47(8), p. 2116, Copyright 1992, with kind permission from Elsevier Science Ltd., The Boulevard, Langford Lane, Kidlington 0X5 1GB, UK). 

Sulfuryl chloride (also known as chlorosulfuric acid and thionyl chloride), SO2CI2, is used in a variety of applications, including the synthesis of pharmaceuticals, rubber-based plastics, dyestuff, and rayon. At a certain temperature, the rate of decomposition of sulfuryl chloride was studied. 

Carbon disulfide (CS2) is one of the most significant sulfur compounds because of its widespread use and toxicity. This compound has two sulfur atoms, each separately bonded to a carbon atom. This compound is a volatile, colorless liquid (mp, -111°C bp, 46°C). Unlike most organosulfur compounds, it is virtually free of odor. Although its uses are declining, it has numerous applications in chemical synthesis, as a solvent to break down cellulose in viscose rayon manufacture, and in the manufacture of cellophane. It has also been used as an insecticide and fumigant. 

The chemistry of ammonia and the ammonium ion is vast ammonia is of immense industrial importance and is produced in larger molar quantities than any other chemical. More than 80% of the ammonia produced is used in fertilizers, with additional uses including the synthesis of explosives, the manufacture of synthetic fibers (such as rayon, nylon, and polyurethanes), and the synthesis of a wide variety of organic and inorganic compounds. As described in Chapter 6, liquid ammonia is used extensively as a nonaqueous ionizing solvent. 

The field of monosaccharides, disaccharides and polysaccharids contains many industrial examples of semi-synthesis, which have entered chemical history, such the hydrolysis of starch to form D-glucose, the esterification of cellulose, the chemistry of rayon and, more recently, advances in the chemistry of carbohydrate surfactants (ref.83). 

Acetic acid is used in the manufacture of various acetates, acetyl compounds, cellulose acetate, acetate rayons, plastics, and rubber. It is also used in tanning, as laundry sour, in printing calico, and in dyeing silk. It is an acidulant and preservative in food. It is a solvent for gums, resins, volatile oils, and many other substances. Acetic acid is widely used in commercial organic synthesis. 

Use Textiles, manufacture rayon, rubber, fertilizers, refrigeration, condensation polymerization, photography (development of latent images), pharmaceuticals, ammonia soaps, lubricants, fireproofing wood, ink manufacture, explosives, ceramics, ammonium compounds, saponifying fats and oils, organic synthesis, detergents, food additives, household cleanser. 

Use Organic synthesis (chlorinating agent, dehydrating agent, acylating agent) pharmaceuticals, dyestuffs, rubber-base plastics, rayon, solvent, catalyst. 

Acetic acid occurs in vinegar. It is produced in the destructive distillation of wood. It finds extensive application in the chemical industry. It is used in the manufacture of cellulose acetate, acetate rayon, and various acetate and acetyl compounds as a solvent for gums, oils, and resins as a food preservative in printing and dyeing and in organic synthesis. 

Carbon disulfide is a volatile organic solvent, used mainly as a starting material in rayon manufacture in the viscose process. It was important historically in the cold vulcanization of rubber. Although no longer used in this form, carbon disulfide is still a major industrial precursor in rubber industry chemical synthesis and has a number of other industrial applications. Carbon disulfide is also widely used as a solvent in a variety of laboratory settings. Carbon disulfide is a metabolite of the drug disulfiram (see pp 186) and is a spontaneous breakdown by-product of the pesticide metam sodium. 

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