1,3-Dioxolan-4-Ones as Promising Monomers for Aliphatic Polyesters: Metal-Free, in Bulk Preparation of PLA

Abstract

The first example of solvent-free, organocatalyzed, polymerization of 1,3-dioxolan-4-ones, used as easily accessible monomers for the synthesis of polylactic acid (PLA), is described here. An optimization of reaction conditions was carried out, with p-toluensulfonic acid emerging as the most efficient Brønsted acid catalyst. The reactivity of the monomers in the tested conditions was studied following the monomer conversion by 1H NMR and the molecular weight growth by SEC analysis. A double activation polymerization mechanism was proposed, pointing out the key role of the acid catalyst. The formation of acetal bridges was demonstrated, to different extents depending on the nature of the aldehyde or ketone employed for lactic acid protection. The polymer shows complete retention of stereochemistry, as well as good thermal properties and good polydispersity, albeit modest molecular weight.

Sustainable formulation polymers for home, beauty and personal care: challenges and opportunities

“…Small molecules sourced from biomass 108 include diacids and diols for stoichiometric polycondensations, 102,109,110 hydroxyacids for polycondensations, [111][112][113][114][115] cyclic monomers for ring opening polymerisations, [116][117][118][119][120][121][122] and agents for branching and crosslinking. 111,123 A notable example utilised across different applications is poly(lactic acid) (PLA), which uses glucose-derived lactic acid as a feedstock.…”

Stereoselective Ring-Opening Deacetonation Polymerization of Racemic 2,2,5-Trimethyl-1,3-dioxolan-4-one by Using Homosalen–Aluminum Complexes: A Novel Approach to Isotactic ­Poly(rac-lactic acid)

“…To the best of our knowledge, the stereoselective polymerization of rac -TDO has never previously been reported. 10…”

“…To the best of our knowledge, the stereoselective polymerization of rac-TDO has never previously been reported. 10 We then evaluated the bulk polymerization of rac-TDO under N 2 at 100 °C using a series of homosalen-Al catalysts 2, previously found to be effective for the highly iso-selective ring-opening polymerization of rac-LA (Table 1). 11 We used 2.5 mol% of the precatalysts 2 12 in the presence of 1 mol% of 2-phenylethyl alcohol, and we successfully obtained P(rac-LAA).…”