Efficient green synthesis of bis(cyclic carbonate) poly(dimethylsiloxane) derivative using CO2 addition: a novel precursor for synthesis of urethanes

Poly(dimethyl siloxane), PDMS, with terminal cyclic carbonate groups was prepared by cycloaddition of carbon dioxide to epoxy rings using tetra alkyl-ammonium bromide as a catalyst under efficient and mild conditions. The process was carried out under a modest pressure of carbon dioxide (i.e., <2 MPa) and temperature (<200 degrees C). The oligomeric species was found to be a non-Newtonian fluid with low molecular weight (MW similar to 1200 g mol(-1)) with n = xx - yy and thermally stable up to 200 degrees C. Its formation was verified by mid infrared spectroscopy (FT-MIR), Matrix-Assisted Laser Desorption Ionization Mass Spectroscopy MALDI-Tof-MS and multinuclear magnetic resonance (C-13 NMR, Si-29 NMR, H-1 NMR). The urethane synthesis was confirmed by FTIR, NMR and X-ray Photoelectron Spectroscopy (XPS) after reacting amines or diamines, in mild reactions conditions, with bis(cyclic carbonate) poly(dimethylsiloxane).