“…Conventional petrochemical diisocyanates (Figure 15), such as MDI, TDI and others, are toxic, hazardous, nonrenewable, and synthesized from poisonous phosgene gas (Llevot et al, 2016;Sawpan, 2018). Thus, NIPUs, such as polyhydroxyurethanes (PHUs) arising from aminolysis of cyclic carbonates with diamines (Figure 28a), serve as environmentally friendly and renewable alternatives (Bizet et al, 2022;Carre et al, 2015Carre et al, , 2019Cornille et al, 2017;Gomez-Lopez et al, 2021;Kreye et al, 2013;Maisonneuve et al, 2015;Nohra et al, 2013). The presence of hydroxy groups adjacent b CTAB, cetyltrimethylammonium bromide; NMP, N-methyl-2-pyrrolidone; SiO 2 -I, silica-supported 4-pyrrolidinopyridinium iodide; TBAB, tetrabutylammonium bromide; X, Br, Cl and I. c CO 2 was continuously bubbled through a solution of reactants at atmospheric pressure.…”