Highly active and robust [DBUH]Br@PILCOOH catalyst for CO2 Cycloaddition: One-pot fabrication via ionic liquid immobilization on poly(ionic liquid)s

Abstract

Global challenges such as climate change and environmental pollution make the efficient utilization of waste CO2 emissions increasingly critical. The cycloaddition of CO2 with epoxides to form cyclic carbonates is an attractive process, integrating waste gas conversion with the production of value-added chemicals. However, the development of catalysts that are both highly efficient and environmentally benign remains a significant challenge. In this study, we report a novel heterogeneous composite ionic liquid catalyst, [DBUH]Br@PILCOOH, featuring a high ionic liquid content synthesized via a simple one-pot process. [DBUH]Br@PILCOOH uniquely combines two types of proton donors acting as Lewis acid centers with a nucleophilic bromide ion (Br-) and a mesoporous polyionic liquid framework. This innovative structure results in exceptional catalytic performance, achieving high yields (95.7~98.6%) and excellent selectivities (>99%) across a wide range of epoxides under mild conditions (ambient CO2 pressure, 80 oC, solvent-free, and without co-catalysts). The synergistic effect of the catalyst's components not only enhances activity but also significantly improves recyclability, maintaining high performance after six cycles with minimal loss of active sites. This represents a substantial advancement over existing catalysts, offering a new avenue for efficient CO2 utilization. Furthermore, the novel approach for preparing such heterogeneous composite ionic liquid catalysts opens up broader environmental applications, paving the way for scalable and eco-friendly CO2 conversion technologies.