Exploring Oxidative NHC‐Catalysis as Organocatalytic Polymerization Strategy towards Polyamide Oligomers
Daniele Ragno, Arianna Brandolese, Graziano Di Carmine, Sara Buoso, Giada Belletti, Costanza Leonardi, Olga Bortolini, Monica Bertoldo, Alessandro Massi
Abstract
Abstract The polycondensation of diamines and dialdehydes promoted by an N‐heterocyclic carbene (NHC) catalyst in the presence of a quinone oxidant and hexafluoro‐2‐propanol (HFIP) is herein presented for the synthesis of oligomeric polyamides (PAs), which are obtained with a number‐average molecular weight ( M n ) in the range of 1.7–3.6 kg mol −1 as determined by NMR analysis. In particular, the utilization of furanic dialdehyde monomers (2,5‐diformylfuran, DFF; 5,5’‐[oxybis(methylene)]bis[2‐furaldehyde], OBFA) to access known and previously unreported biobased PAs is illustrated. The synthesis of higher molecular weight PAs (poly(decamethylene terephthalamide, PA10T, M n = 62.8 kg mol −1 ; poly(decamethylene 2,5‐furandicarboxylamide, PA10F, M n = 6.5 kg mol −1 ) by a two‐step polycondensation approach is also described. The thermal properties (TGA and DSC analyses) of the synthesized PAs are reported.