Production of Terephthalic Acid from Waste Polyethylene Terephthalate) Materials

Abstract

A comparative study of hydrolysis of PET waste 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 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 the terephthalic acid. The basic hydrolysis of the PET waste (in a minimum amount of water) is being recommended as preferred method for the formation of terephthalic acid.

A Rapid, Economical, and Eco-Friendly Method to Recycle Terephthalic Acid from Waste Poly (Ethylene Terphthalate) Bottles

“…In our previous work [1], it was found that alkaline hydrolysis of the PET leads to better results in comparison to acidic hydrolysis. In the present work, caustic soda was melted in a china clay crucible by heating on a SiC slab that was heated with microwaves of 2.45 GHz frequency.…”

“…Poly (ethylene terephthalate), commonly known as PET, is often used in manufacturing of soft drink bottles, audio and video films, thermoformed articles, as well as textile fibers [1]. Because of its light weight, transparency, easy moldability, and good strength, PET is considered one of the best packing plastics [1].…”

“…Because of its light weight, transparency, easy moldability, and good strength, PET is considered one of the best packing plastics [1]. Around the world, used PET articles and bottles are not properly recycled=degraded and usually end as landfill refuse.…”

“…Scientists around the world are trying to develop a quick and efficient method to recycle=degrade PET [7][8][9][10][11][12]. Accordingly, performance of various catalysts [13], different solvent systems [14,15], and chemicals [1,9,12,16] has been tested to evaluate their ability to degrade PET.…”

“…In our previous work [1], it was found that when PET chips were heated to dryness in the presence of concentrated aqueous solution of sodium hydroxide, terephthalic acid (TPA) has been recovered up to 99% in nearly 10 minutes. In the present work, the same reaction was carried out in a china clay crucible placed on a silicon carbide (SiC) slab that was heated with 2.45 GHz microwaves in a domestic microwave oven.…”