Efficient cycloaddition of carbon dioxide with epoxide to produce five-membered cyclic carbonates by amine-functionalized silicoaluminophosphates molecular sieves

Abstract

The synthesis of functionalized microporous materials as very effective catalysts is a significant and rapidly increasing research topic with the goal for providing more efficient energy alternatives and contributing to the reduction of atmospheric CO2 levels. Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, contributing to global warming and climate change. SAPO-5 and SAPO-34 molecular sieves were post-synthetically –NH2 functionalized, and the existence of –NH2 functionalities in the SAPO structure wall was demonstrated by FT-IR, CHN analysis. Powder XRD confirmed the crystalline structures of the modified SAPO-34 materials with amine functionalities. FE-SEM examined the morphology of the materials. The functionalized silicoaluminophosphate materials were investigated in the cyclo-addition of CO2 to epoxide (cyclohexene oxide and styrene oxide), where the catalytic performance of post-synthetically functionalized materials as catalyst were found to be superior. The amine group of the silicoaluminophosphates materials were essential for the activation of CO2. For treated SAPO-34, reactant conversion in cyclohexene oxide and styrene oxide was reported to be 94% and 93%, respectively. Because of the high recyclability of these materials, the catalysts are found to be both cost-effective and environmentally benign.