Alkaline Hydrolysis of Waste Poly(Ethylene Terephthalate): A Modified Shrinking Core Model

A kinetic study of the depolymerisation of poly(ethylene terephthalate) by phase transfer catalysed alkaline hydrolysis

“…DSC analysis of fresh and residual flakes suggested that remaining PET particles after reaction maintained their original structure, thus suggesting that the process of depolymerisation in sodium hydroxide solution occurred on the external surface of the flakes, and these were lamellarly depolymerised. 25 This was consistent with the observed decrease in PET particle size with increasing conversion (Fig. 4).…”

Kinetics of the hydrolytic depolymerization of poly(ethylene terephthalate) under microwave irradiation

“…This finding was consistent with the results of related studies, which pointed to the fact that the molecular chain is broken to a certain extent in the process of PET hydrolysis. 19 Moreover, there were additional clear drops in the value of the M n at the depolymerization times of 150, 210 and 300 min for the temperatures of 190 1C, 185 1C and 180 1C, respectively, and this was in line with the results of the C COOH changes for different temperatures.…”

Chemical recycling of PET by alkaline hydrolysis in the presence of quaternary phosphonium and ammonium salts as phase transfer catalysts

“…On the other hand, results from titration revealed that high purity TPA was the major solid product obtained after neutralisation. DSC analysis of fresh and residual flakes suggested that remaining PET particles after reaction maintained their original structure, this suggesting that the process of depolymerisation in sodium hydroxide solution occurred on the external surface of the flakes, and these were lamellarly depolymerised [7]. This was consistent with the observed decrease in PET particle size with increasing conversion.…”

“…Within the context of alkaline hydrolysis of PET a potentially active PTC should efficiently transport the hydroxide anion from the aqueous phase to the organic phase (solid PET), thereby increasing the reaction rate. Recent studies have only evaluated the role of quaternary ammonium salts [ 1 [2][3][4][5][6][7][8][9][10][11][12][13][14]; however, no attention has been paid to examining the behaviour of tetralkyl phosphonium salts as PTCs (table 1) for this specific reaction system. For this screening study the following operating conditions were used: stirring rate 400 rpm, particle size 250 µm, inert atmosphere 200 kPa N 2 , temperature 80 ºC, NaOH concentration 1.67 mol l -1 , PET concentration 0.29 mol l -1 , and PTC concentration 0.07 mol l -1 .…”