Utilization of carbon dioxide has been the goal of the century, as demands for the reduction of greenhouse gas grows larger than ever. Several chemical routes have been discovered to convert carbon dioxide into valuable chemicals. One of the best routes that have been discovered so far is the fixation of CO2 with epoxides to form 5-membered cyclic carbonates, as it is 100% atom efficient and can be conducted in a solvent-free manner. For feasible reaction kinetics, many catalysts have been developed so far, such as salens, ionic liquids, metal organic frameworks, and porphyrins. Porphyrin-based catalysts have shown to possess high converting abilities in mild reaction conditions, and many attempts have been made to modify the structure of porphyrins for enhanced catalytic activities. In this work, we have newly synthesized four different bifunctional porphyrin-based catalysts with imidazolium-halogen based side chains attached to its structures. The structures of the porphyrin-based catalysts differed in the presence/absence of an alkyl chain spacer, the substitution place of the alkyl spacers, and steric hindrance near the metal atom center. All porphyrin-based catalysts were subjected to CO2 utilization reactions, and the catalytic activities of the catalysts were evaluated using the convergence of the reaction. The newly synthesized bifunctional porphyrin-based catalysts are expected to be utilized in CO2-epoxide cycloaddition reactions as a highly efficient catalyst with easy synthesis routes and short purification steps after the reaction.
지구 온난화의 주범인 이산화탄소는 지난 수십년간 지속적으로 발생량이 증가했으며, 지구 온난화도 가속하여 100년 전보다 지구 평균 온도가 1.09도 증가하였다. 이산화탄소는 여러 촉매들을 이용하여 여러 가치가 높은 제품을 창출할 수 있다. 특히 포르피린 기반의 촉매는 우수한 촉매 능력과 상대적으로 쉬운 촉매 합성 조건으로 많은 주목을 받아왔다. 본 연구에서는 포르피린 기반 촉매에 이미다졸-계열의 “손-팔” 작용기를 부착하여 대기압과 낮은 온도에서 이산화탄소를 고리형 카보네이트로 빠르게 전환하는 촉매 능력을 향상시키는 것에 초점을 맞출 것이다.
