La(iii)-Catalysed degradation of polyesters to monomersviatransesterifications

Abstract

Tris(acetylacetonato)lanthanum(III) (1 mol%) catalyses the degradation of poly(butylene succinate) (Mw = 90,700) by transesterification in MeOH at 90 ˚C for 4 h, thus affording dimethyl succinate (>99% yield) and 1,4-butanediol...

Diverse Alkyl–Silyl Cross-Coupling via Homolysis of Unactivated C(sp3)–O Bonds with the Cooperation of Gold Nanoparticles and Amphoteric Zirconium Oxides

“…Since the accumulation of waste plastics is recognized as a serious modern environmental issue, considerable attention has been focused on the discovery of novel methods for the degradation of plastics . Even though the hydrolysis of polyesters by the use of a stoichiometric amount of strong base can deconstruct their robust structure into monomers, this process provides only the starting substances, namely, diols and dicarboxylic acids. Furthermore, neutralization of alkali salts into carboxylic acids by acids has a considerable negative impact on the environment and reaction facility.…”

Depolymerization of Polyester Fibers with Dimethyl Carbonate-Aided Methanolysis

“…In this context, we recently achieved an efficient PET depolymerization reaction, dimethyl carbonate-aided methanolysis (DCAM) (Scheme ), in which the product (i.e., dimethyl terephthalate [DMT]) is available for PET production . While methanolysis is a classical method for PET depolymerization, − it is difficult to achieve high depolymerization efficiency under mild conditions due to the reaction equilibrium (Scheme (eq 1)). In the DCAM method, dimethyl carbonate (DMC) is added to trap EG to form thermodynamically stable ethylene carbonate (EC) as well as MeOH (Scheme (eq 2)).…”

Highly selective pressure-dependent (transfer) hydrogenative depolymerization of polybutylene succinate

“…1 b Although PBS is biodegradable, converting it to useful molecules for other applications would carry environmental benefits. To date, PBS depolymerization efforts include hydrogenation to tetrahydrofuran, 11 transesterification, 12 hydrolysis, 13 melt processing, 14 or enzymatic degradation. 15 Recent heterogeneous catalytic hydrogenation 16 and reductive depolymerization with pinacolborane 9 a , b yielded the corresponding diols and diboranes.…”