Transesterification of Methyl-10-undecenoate and Poly(ethylene adipate) Catalyzed by (Cyclopentadienyl)titanium Trichlorides as Model Chemical Conversions of Plant Oils and Acid-, Base-Free Chemical Recycling of Aliphatic Polyesters

Abstract

Highly active and exclusive transesterifications of methyl 10-undecenoate with alcohols (cyclohexanemethanol, 1,4-cyclohexanedimethanol, 10-undecen-1-ol, 3-hexanol) have been demonstrated by Cp′TiCl3 (Cp′ = Cp, C5Me5) at 100–120 °C. The CpTiCl3 enabled depolymerization of poly­(ethylene adipate) by the transesterification (>99% conv., 0.25–0.5 mol % Ti) at 120 °C; the depolymerization completed after 6 h at 150 °C (0.5 mol % Ti).

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

“…Moreover, the resultant saturated polymer (HP1) could be depolymerized by transesterification with ethanol (150 °C and 6 h) in the presence of CpTiCl 3 (1.0 mol %), as reported previously 71 for the depolymerization of poly(ethylene adipate) and poly(butylene adipate). The resultant reaction mixture consisted of isosorbide and diethyl eicosane dioate 3).…”

“…Moreover, the resultant saturated polymer ( HP1 ) could be depolymerized by transesterification with ethanol (150 °C and 6 h) in the presence of CpTiCl 3 (1.0 mol %), as reported previously 71 for the depolymerization of poly(ethylene adipate) and poly(butylene adipate). The resultant reaction mixture consisted of isosorbide and diethyl eicosane dioate (EtO 2 C(CH 2 ) 18 CO 2 Et) exclusively with the isolation of the diester (96% isolated yield), which was confirmed by the 1 H NMR spectra ( Scheme 5 , the procedure and the NMR spectra are shown in the Supporting Information ).…”

Synthesis of High Molecular Weight Biobased Aliphatic Polyesters Exhibiting Tensile Properties Beyond Polyethylene

“…Aliphatic polyesters derived from plant resources are attracting considerable attention − not only as an alternative of petroleum-based polymers but also in terms of their circular economy − due to rather facile chemical recycling by the depolymerization (through transesterification, etc. ) − compared to conventional polyolefins. These polyesters would also provide a possibility as new promising materials with better mechanical properties through interpolymer interactions as well as better compatibility with biobased fibers (described below).…”

Synthesis of Network Biobased Aliphatic Polyesters Exhibiting Better Tensile Properties than the Linear Polymers by ADMET Polymerization in the Presence of Glycerol Tris(undec-10-enoate)

“…This is not only because these are considered alternatives to petroleum-based polymers but also because of their importance from the viewpoint of circular economy [ 9 , 10 , 11 ]. For example, these polyesters (including conventional polyesters) can be depolymerized by treating them with alcohols (via transesterification) in the presence of a catalyst to recover monomers exclusively (facile chemical recycling) [ 12 , 13 , 14 , 15 ]; one-pot closed-loop chemical recycling (depolymerization and repolymerization) was thus also demonstrated [ 13 ]. There have been thus many reports on the synthesis of polyesters derived from plant oil through polycondensation [ 7 , 15 , 16 , 17 , 18 , 19 ] and acyclic diene metathesis (ADMET) polymerization technique [ 7 , 17 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ].…”

“…We thus herein report the synthesis of network biobased aliphatic polyesters, which show better tensile properties (tensile strengths and elongation at breaks) than the linear one ( HP1 ). These polymers were also depolymerized to afford the corresponding diesters and diols (and triols) through transesterification with ethanol in the presence of CpTiCl 3 [ 12 , 14 ].…”