Plastics manufacturing, chemicals used benzoic acid

Benzoic Acid. Ben2oic acid is manufactured from toluene by oxidation in the liquid phase using air and a cobalt catalyst. Typical conditions are 308—790 kPa (30—100 psi) and 130—160°C. The cmde product is purified by distillation, crystallization, or both. Yields are generally >90 mol%, and product purity is generally >99%. Kalama Chemical Company, the largest producer, converts about half of its production to phenol, but most producers consider the most economic process for phenol to be peroxidation of cumene. Other uses of benzoic acid are for the manufacture of benzoyl chloride, of plasticizers such as butyl benzoate, and of sodium benzoate for use in preservatives. In Italy, Snia Viscosa uses benzoic acid as raw material for the production of caprolactam, and subsequendy nylon-6, by the sequence shown below. 

In the United States all other processes have been completely phased out and virtually all benzoic acid is manufactured by the continuous hquid-phase air oxidation of toluene. In the late 1950s and the early 1960s both Dow Chemical and Snia Viscosa constmcted faciUties for Hquid-phase toluene oxidation because of large requirements for benzoic acid in the production of phenol and caprolactam. Benzoic acid, its salts, and esters are very useful and find appHcation in medicinals, food and industrial preservatives, cosmetics, resins, plasticizers, dyestuffs, and fibers. 

OTHER COMMENTS used in the manufacture of phthaleins, phthalates, benzoic acid, synthetic indigo, and artificial resins used as a chemical intermediate for dioctyl phthalates, phthalate plasticizers, and many phthalate esters used as a hardener for resins and polyesters employed in the synthesis of phenolphthalein, chlorinated products, diethyl phthalate, dimethyl phthalate, and pharmaceutical intermediates. 

Plasticizers, which are added to improve the flexibility, softness and processibility of plastics, constitute a broad range of chemically and thermally stable products of a variety of chemical classes. Their principal use is in thermoplastic resins, and 80-85% of the world s production of plasticizers are used in polyvinyl chloride (PVC) manufacturing. Approximately 450 plasticizers are commercially available. Many are esters of carboxylic acids (e.g. phthalic, isophthalic, adipic, benzoic, abietic, trimellitic, oleic, sebacic acids) or phosphoric acid. Other plasticizers are chlorinated paraffins, epoxidized vegetable oils and adipate polymers. 

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