I-LDH as a heterogeneous bifunctional catalyst for the conversion of CO2 into cyclic organic carbonates

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 degrees 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.

Automated summary

In this study, a new active heterogeneous, single-component catalyst (I-(Mg/Al)LDH) was prepared for the cycloaddition reaction of CO2 to epoxides. The catalyst I-LDH selectively catalyzed this reaction to cyclic organic carbonates. The mechanistic investigation revealed that iodide anions within the interlayer and the hydroxide group of LDH cooperated in the cycloaddition reaction. The optimized reaction conditions yielded a conversion of up to 47% and a total selectivity to the cyclic carbonate using propylene oxide as the model compound, and promising results were obtained with other commercial epoxides.