Dual-porous metal organic framework for room temperature CO2 fixation via cyclic carbonate synthesis
A novel approach of employing a dual-porous metal organic framework (MOF) in CO2 fixation at room temperature was demonstrated using a micro–mesoporous MOF, UMCM-1-NH2, in the synthesis of various five-membered cyclic carbonates under solventless conditions. Mesopores allow easy guest diffusion and molecular accessibility, while micropores are predominantly helpful in regulating the catalytic interactions in active centres; thus outperforming the properties of pure microporous or pure mesoporous MOFs in cycloaddition. Structural features, acid–base characteristics and physical properties were studied in detail for carrying out a systematic investigation on the cooperative influences of porosity, functionalization and synergism with quaternary ammonium salts in the cycloaddition reaction of CO2 with propylene oxide, so as to arrive at the underlying mechanism. The catalyst was totally recyclable up to five times without compromising the activity and the extent of heterogeneity was also studied. The effects of various reaction parameters like catalyst–cocatalyst ratio, reaction time and reaction temperature have been investigated.