Alkaline Solvolysis of Poly(Ethylene Terephthalate) in Butan–1–ol Media: Kinetics and Optimization Studies

Abstract

This study was carried out to examine the thermo-chemical decomposition of postconsumer poly(ethylene terephthalate) (PET) in alkaline solution of butan-1-ol. The effect of various process parameters such as reactor temperature, time and sodium hydroxide concentration on the degree of PET degradation and products yield were studied and it was found that the decomposition of PET was essentially complete in an hour, with terephthalic acid and ethylene glycol being the main products. A kinetic study of the process showed that the alkaline solvolysis of PET is a second order reaction.

Effect of Flake Pigmentation on the Microwave-Assisted Alkaline Solvolysis of Postconsumer Polyethylene Terephthalate in Primary C1 – C3 Aliphatic Alcohols

“…However, the trend observed in Figs. 2-4 suggests an initial lag in conversion rate for the methanol medium due to the formation of a layer of intermediate products on the flakes, according to the kinetic model reported in an earlier work for the alkaline solvolysis of PET using NaOH in butanol media [26].…”

“…For ethanol and propan-1-ol media, the microwave-assisted reactions gave a higher conversion, although the general trend is not different from that reported in a previous work [24]. Based on the theory of PET alkaline solvolysis, the expected primary product is terephthalic acid [24,26]. For each experiment, a white powder was obtained and was subsequently subjected to various physical and chemical tests.…”

“…Studies done so far on the alkaline solvolysis of postconsumer PET in alcoholic media showed that it is possible to decompose PET according to the reaction mechanisms shown below [24,26]:…”

Comparsion of Catalyst Effectiveness in Different Chemical Depolymerization Methods of Poly(ethylene terephthalate)

“…Three reactions take place under alkaline catalysis (NaOH) in a water-ethanol medium: depolymerization of PET to a mixture of diethyl terephthalate (Step I), its hydrolysis to TPA disodium salt (Step II) and precipitation of free TPA (Step III, Figure 6). Ethanol is recycled and can be reused (Closed-loop recycling process), making it very competitive with conventional alkaline hydrolysis processes [24,79,80]. The process can be carried out under relatively mild conditions (reaction temperature 50-80 • C, the proportion of ethanol to water 20-100 vol%, the amount of NaOH 5-15%wt) [81].…”

One-Step Synthesized Solid Acid Catalyst with High Zr Content for Efficient and Green PET Degradation in Supercritical CO2

“…Typically, acid − or lye, ,, catalysts are employed for the hydrolysis of PET; however, this approach necessitates subsequent treatment of a substantial quantity of waste acid and alkali, leading to energy consumption and environmental contamination. To address this issue, Li et al employed a solid super acid catalyst, SO 4 2– /TiO 2 , for the catalytic hydrolysis of PET.…”