Hsieh Andrew Y, Haines Ronald S, Harper Jason B
School of Chemistry, University of New South Wales UNSW Sydney NSW 2052 Australia
RSC Adv. 2023 Jul 12;13(30):21036-21043. doi: 10.1039/d3ra04302a. eCollection 2023 Jul 7.
The reaction of a chlorobenzene in mixtures containing ethanol and eight different ionic liquids was investigated in order to understand the effects of varying proportions and constituent ions of an ionic liquid on the rate constant of the process. The results were found to be generally consistent with previously studied reactions of the same type, with small proportions of an ionic liquid resulting in a rate constant increase compared to ethanol and large proportions causing a rate constant decrease. Temperature dependent kinetic studies were used to interpret the changes in reaction outcome, particularly noting an entropic cost on moving to high proportions of ionic liquid, consistent with organisation of solvent around the transition state. While attempts to use empirical solvent parameters to correlate outcome with the ionic liquid used were unsuccessful, use of recently acquired nucleofugality data for chloride and estimations for the electrofuge allowed for excellent prediction of the effects of ionic liquids, with rate constants quantitatively predicted in systems containing both different proportions of ionic liquid (mean absolute error (MAE) log() = 0.11) and different ionic liquids (MAE log() = 0.33). Importantly, this demonstrates the ready application of these quantitative reactivity parameters.
为了了解离子液体不同比例和组成离子对该过程速率常数的影响，研究了氯苯在含有乙醇和八种不同离子液体的混合物中的反应。结果发现，这些结果与之前对相同类型反应的研究总体一致，与乙醇相比，少量离子液体导致速率常数增加，而大量离子液体则导致速率常数降低。利用温度相关的动力学研究来解释反应结果的变化，特别注意到在向高比例离子液体转变时的熵成本，这与过渡态周围溶剂的组织情况一致。虽然试图使用经验溶剂参数将结果与所用离子液体相关联未成功，但使用最近获得的氯离子离去倾向数据和对亲电体的估计能够出色地预测离子液体的影响，在含有不同比例离子液体（平均绝对误差（MAE）log() =
0.11）和不同离子液体（MAE log() = 0.33）的体系中都能对速率常数进行定量预测。重要的是，这证明了这些定量反应性参数的易于应用。
