Heteroatom driven activation and conversion of CO₂using cyclophosphazene based inorganic-organic hybrid nanoporous materials

Inexpensive and nontoxic metal-free heteroatom (P, N, and O) enriched high surface area nanoporous materials (CHNM and HNM) as efficient heterogeneous catalysts for the conversion of epoxides to cyclic carbonates by utilizing CO₂is reported. The catalysts were made by condensing the heteroatom enriched precursor with melamine and pyrrole to produce HNM and CHNM, respectively. The catalysis was carried out under mild experimental conditions,i.e.100 °C reaction temperature and 4 bar CO₂pressure under solvent-free conditions. Almost 100% conversion can be realized using HNM as a catalyst and this superior performance was attributed to the presence of larger heteroatoms as compared to CHNM, although the latter has 159% specific surface area and 115% pore volume as compared to the former. The obtained results are discussed in terms of the Lewis acid-Lewis base interaction, textural properties and the frameworks of the catalysts and the reactants.