Copolymerization of carbon dioxide and oxetane catalyzed by aluminum porphyrin complex system

Abstract Tetraphenylporphinatoaluminum chloride ([TPP]AlCl) catalyst and tetra‐n‐butylammonium bromide (TBAB) cocatalyst system is effective for the copolymerization of CO2 and oxetane even under low CO2 pressure (~2 MPa). In the presence of toluene as a solvent, poly(trimethylene carbonate) (PTMC) containing >99% of carbonate linkages with Mn = 8600 and Mw/Mn = 1.70 was synthesized. This is the first report of PTMC formation with excellent ratio of carbonate linkages from oxetane and CO2. According to the kinetic analysis, proton nuclear magnetic resonance (1H NMR) and matrix assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF/MS) measurements of the products, PTMC was mainly synthesized via (i) the trimethylene carbonate (TMC) formation from CO2 and oxetane and (ii) the successive ring‐opening polymerization of TMC.