Glycolytic Aminolysis of Poly (Ethylene Terephthalate) Waste at Atmospheric Pressure for Recovery of a Value Added Insecticide

Abstract

: Reaction of poly (ethylene terephthalate) waste (PETW) powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol zinc acetate as a catalyst was carried out in a batch reactor at 470 K and at atmospheric pressure. Reactions were undertaken with various particle size ranges from 50–512.5 µm, and reaction time from 30–70 min at 10 min intervals for reaction of PETW. A low molecular weight product of PETW was obtained during this step. In the next stage hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide solution were introduced to convert the low molecular weight product of PETW into terephthalohydroxamic acid (TPHA) by introduction of HCl as per stoichiometric requirement. The TPHA is used as insecticide, and it is highly expensive. To increase the PETW conversion rate, an external catalyst (zinc acetate) was introduced during the reaction. The product was deposited on the surface of unreacted PETW that was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate DMSO, CHA, and THF were introduced during the reaction, which had an industrial significance. Depolymerization of PETW was proportional to the reaction time. Depolymerization of PETW was inversely proportional to the particle size of PETW. Analyses of value added products (TPHA and EG) as well as PETW were undertaken. A kinetic model was developed and experimental data simulated with it that were consistent with the model. A thermodynamic study was undertaken as this is required during transfer of laboratory data through a pilot plant for commercialization.