Efficient and Reusable Metal Heterogeneous Catalysts for Conversion of CO2 Prepared from a Microwave Synthetized Porous Polyiminopyridine

A stable nitrogen-rich porous polyimine containing pyridine units (PIPy-4Mw) was successfully synthesized under microwave heating via a simple one-step polycondensation in only 30 min without adding any catalyst. This versatile polymer can incorporate different transition metals leading polyiminopyridine-supported catalysts; in this paper we report the synthesis and catalytic performance of heterogenized complexes of abundant earth metals such as iron(II), cobalt(II) and chromium(III) (PIPy-4MwFe, PIPy-4MwCo and PIPy-4MwCr). These supported metal-polyiminopyridines have been applied as heterogeneous catalysts in the conversion of CO2 into cyclic carbonates, an interesting reaction to recycle CO2, and in another eco-friendly reaction: the synthesis of additives for diesel fuels by acetalization of furfural. The cobalt and iron complexes have showed high efficiency and were reused without any significant change in their activities.