I-LDH as a heterogeneous bifunctional catalyst for the conversion of CO2 into cyclic organic carbonates
Francesca Fierro, David Herman Lamparelli, Alessandra Genga, Raffaele Cucciniello, Carmine Capacchione
Abstract
In this work, we prepared a new active heterogeneous, single-component, catalyst (I-(Mg/Al)LDH) for the cycloaddition reaction of CO2 to epoxides. I-LDH was able to catalyze this reaction selectively to cyclic organic carbonates. From a mechanistic point of view, iodide anions within the interlayer and the hydroxide group of the LDH cooperate in the cycloaddition reaction. The reaction conditions (T = 80 °C, 2 MPa of CO2, methyl ethyl ketone as a solvent, PO:I-LDH wt ratio of 1.7, 24 h) were optimized using propylene oxide, with a conversion up to 47% and a total selectivity to the cyclic carbonate and then the study was extended to other commercial epoxides with encouraging results. The reversible I-LDH poisoning due to the absorption of CO2 as unreactive carbonate interlayer anion was also investigated and the catalyst was reactivated by treatment in a concentrated KI aqueous solution.