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A comparative study of hydrolysis of PET waste and other plastic waste (compact discs, polyethelene, polystyrene) has been carried out under various reaction conditions. PET was hydrolyzed with sodium hydroxide in different solvents at reflux, as well as by fusion in solventless conditions at atmospheric pressure. Best results were obtained when PET chips were heated to dryness with sodium hydroxide in a minimum amount of water. A 98% yield of terephthalic acid was obtained in ten minutes. Hydrolysis with aqueous ammonia was not promising. Acid hydrolysis with nitric acid also provided 97% yield of terephthalic acid. The basic hydrolysis of PET waste (in a minimum amount of water) is being recommended as the preferred method for formation of terephthalic acid.
In another study compact discs were also recycled by fusion with sodium hydroxide to get bisphenol-A. Sixty percent yield of bisphenol-A was obtained. Polyethylene and polystyrene waste were recycled by acid hydrolysis and distillation processes.
