Metal-Containing Ionic Liquids as Synergistic Catalysts for the Cycloaddition of CO₂: A Density Functional Theory and Response Surface Methodology Corroborated Study

Abstract

Metal-containing ionic liquids possessing bifunctional moieties were identified as efficient catalysts for the synthesis of propylene carbonate (PC) from CO 2 and propylene oxide under moderate and solvent free conditions. Density functional theory calculations were performed to rationalize the difference in catalytic activities of the metalcontaining ionic liquid catalysts (MeIm) 2 MCl 2 , where M was Fe, Cu, or Zn. (MeIm) 2 ZnCl 2 was the most efficient catalyst for the chemical fixation of carbon dioxide in terms of efficiency and environmental benignity. Process optimization using response surface methodology was performed, and the interactions between the operational variables were elucidated. The optimum reaction conditions for maximum PC yield were 4.6 h, 124 °C, and 9 bar which were obtained by a Box−Behnken design with the minimum number of reaction tests. Under the optimum reaction conditions, the predicted and validated yields of PC were 98.37 and 97.91 ± 0.02%, respectively.

Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

“…If combined with suitable organicc ations, these units are the basis for a large group of MILs, the halidometallate ILs, which arguablyi s the largest subgroup of MILs studied today. [10,11,[27][28][29][30][31][32][33][34][35][36] However,a lthough many different metals are in principle amenablet ot he synthesis of halidometallateI Ls, there are still only few reports on MILs containing more than one metal. Very recently,L iu et al [37] demonstrated mixed metal ILs by combining monometallic ILs with an additional metal salt.…”

“…; X=Cl, Br, I) unit. If combined with suitable organic cations, these units are the basis for a large group of MILs, the halidometallate ILs, which arguably is the largest subgroup of MILs studied today [10, 11, 27–36] …”

Cycloaddition Reactions of Epoxides and CO2 by the Novel Imidazolium‐Functionalized Metalloporphyrins: Optimization and Analysis using Response Surface Methodology

“…It is not only time‐consuming, but also unlikely to reflect the interactions among the parameters. Response surface methodology (RSM) is a very useful technique for the prediction of the most efficient sets of conditions with minimum number of tests . It also provides statistical models for assessing the influence of the parameters on the reaction.…”

Bifunctional Catalysts Containing Zn(II) and Imidazolium Salt Ionic Liquids for Chemical Fixation of Carbon Dioxide

“…The BMMs−Zn&ILs‐1.7 shows the highest yield of 98% with the selectivity of 97%. It was explained that the cooperation catalysis between Zn and ILs promoted the ring addition reaction, and the Zn acted as an assistant catalyst when it was used together with ILs for the synthesis of CO 2 with PO to PC [7d] . Moreover, It is well known that halide anions have a significant effect on the catalytic reactivity, which is strongly depend on the order of halide ion nucleophilicity (Cl − <Br − <I − ).…”

“…So far, zinc salts have been proven to be the best candidate, because of its high activity and low toxicity [7d,8a] . For example, the activity of catalysts could be increased about 15.5 or 27 times by adding ZnBr 2 compare to bare 1‐butyl‐3‐methylimidazolium chloride ([C 4 ‐mim]Cl) or tetrabutylammonium iodide respectively [8] .…”