Reaction kinetics investigation of Malononitrile with substituted benzaldehydes in aqueous solutions of ethaline as deep eutectic solvent

Abstract

AbstractDue to increasing demands for ecofriendly processes within the framework of green chemistry, and having shown substantial properties, especially in terms of toxicity, biodegradability, cost, and ease of preparation under ambient conditions, deep eutectic solvents (DESs) have become a suitable candidate as green solvents for reaction media in the past decade. In this work, condensation reaction of some para‐ and meta‐substituted benzaldehydes and Malononitrile was kinetically investigated in ethylene glycol‐choline chloride (ethaline) as a DES mixed with water, in the whole range of mole fractions, at room temperature. The correlation of second‐order rate coefficients based on Hammett's substituent constants yield a linear straight line with positive slope in different mole fractions of ethaline–water mixtures. The measured second‐order rate coefficients of the reaction showed a dramatic variation in ethaline–water mixtures with the increasing mole fraction of water.