Kinetics study of a Diels‐Alder reaction in mixtures of an ionic liquid with molecular solvents |
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Authors: | Ali Reza Harifi‐Mood Aziz Habibi‐Yangjeh Mohammad Reza Gholami |
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Institution: | 1. Department of Chemistry, Sharif University of Technology, Tehran, Iran;2. Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil, Iran |
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Abstract: | The second‐order rate constants for cycloaddition reaction of cyclopentadiene with naphthoquinone were determined spectrophotometrically in various compositions of 1‐(1‐butyl)‐3‐methylimidazolium terafluoroborate (bmim]BF4) with water and methanol at 25 °C. Rate constants of the reaction in pure solvents are in the order of water > bmim]BF4 > methanol. Rate constants of the reaction decrease sharply with mole fraction of the ionic liquid in aqueous solutions and increase slightly to a maximum in alcoholic mixtures. Multi‐parameter correlation of logk2 versus solute–solvent interaction parameters demonstrated that solvophobicity parameter (Sp), hydrogen‐bond donor acidity (α) and hydrogen‐bond acceptor basicity (β) of media are the main factors influencing the reaction rate constant. The proposed three‐parameter model shows that the reaction rate constant increases with Sp, α and β parameters. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | ionic liquid Diels‐Alder solvent effect |
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