Polymer-Supported Zn-Containing Imidazolium Salt Ionic Liquids as Sustainable Catalysts for the Cycloaddition of CO₂: A Kinetic Study and Response Surface Methodology

Abstract

Metal-containing ionic liquids (MIL) are highly active homogeneous catalysts for the chemical fixation of CO2 into epoxides yielding five-membered cyclic carbonates. To obtain sustainability, polymer-supported MIL catalysts were designed to overcome their previously reported inherent poor recoverability. Polymer-supported Zn-containing imidazolium salts, PS-(Im)2ZnX2, possessing bifunctional properties were identified as sustainable catalysts for the activation of CO2 under solvent-free conditions. PS-(Im)2ZnX2 showed good catalytic performance and was readily recoverable and reusable in the subsequent reaction cycles for the cycloaddition of CO2 to propylene oxide. Kinetic studies for the cycloaddition of CO2 to propylene carbonate using batch or semibatch systems were performed to calculate the approximate rate constants, which provide an explanation for the different reaction systems. In addition, process optimization using the response surface methodology was performed, and the interactions between the operational variables were identified. The results demonstrate the advantage of the semibatch system, which allows the completion of the reaction in less time than when using the batch system.

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.…”

Water-Tolerant DUT-Series Metal–Organic Frameworks: A Theoretical–Experimental Study for the Chemical Fixation of CO2 and Catalytic Transfer Hydrogenation of Ethyl Levulinate to γ-Valerolactone

“…The synthesis of five-membered cyclic carbonates through the artificial fixation of CO 2 with epoxides has received much acclaim because it is an atom-economical example of green principles (Scheme ). − Cyclic carbonates are widely used for various purposes, including as electrolytes in Li-ion batteries, raw materials for cosmetics, and pharmaceuticals. − …”

On the real catalytically active species for CO2 fixation into cyclic carbonates under near ambient conditions: Dissociation equilibrium of [BMIm][Fe(NO)2Cl2] dependant on reaction temperature

“…[60,61] To the best of our knowledge, only a few examples have been reported in which well-defined metal-containing ILs were used as catalysts for the cycloaddition of CO2 to epoxides. [62][63][64][65] In the present work we report the use of a novel imidazolium based iron-containing ionic liquid [BMIm][Fe(NO)2Cl2] (BMIm = 1-n-butyl-3-methyl-imidazolium) as a bifunctional catalyst for the indepth study and understanding of the formation mechanism of cyclic carbonates via cycloaddition of CO2 with epoxides by metal-containing ILs. To this end, we have employed µ,µ'-dichlorotetranitrosyl-diiron ([Fe(NO)2Cl]2) as metallic precursor for the formation of the Fe-based ionic liquid.…”