Protic acid assisted synthesis of new materials from a carbon dioxide derived disubstituted lactone precursor

Abstract

The exploitation of carbon dioxide as a feedstock for the synthesis of disubstituted lactones has witnessed an enormous recognition lately. Several attempts have recently been made to employ disubstituted lactones into the chemistry of polymerization by overcoming their thermodynamic stability. The current research reveals the cationic polymerization of carbon dioxide derived disubstituted lactone (α-ethylidene, δ-vinylvalerolactone: EVV) in the presence of a highly reactive protic acid via a solvent-free process. A reaction mechanism for the protic acid assisted polymerization of EVV is proposed, where the vinyl group undergoes reaction to form polymers having a short chain length followed by chain transfer resulting in olefinic terminals. The cationic polymerization product undergoes hydrolysis to form a polymeric structure with hydrolyzed side groups, followed by dehydration resulting in a carboxyl group and an olefinic moiety in the side groups. The molecular weight and structure of the cationic polymerization product are determined by MALDI-TOF mass spectrometry and NMR spectroscopic analyses. The application of metal-free initiating system into the polymerization of carbon dioxide derived disubstituted lactone thus results in the formation of new materials that may serve as essential benchmarks for the sustainable future chemistry.