Solvent effects on kinetics of an aromatic nucleophilic substitution reaction in mixtures of an ionic liquid with molecular solvents and prediction using artificial neural networks

Abstract

Kinetics of the reaction between 1-chloro-2,4-dinitrobenzene and aniline was studied in mixtures of [EtSO 4 ]) with methanol, chloroform, and dimethylsulfoxide at 25 • C. Single-parameter correlations of log k A versus normalized polarity parameter (E N T ), hydrogen-bond acceptor basicity (β), hydrogen-bond donor acidity (α), and dipolarity/polarizability (π * ) of media do not give acceptable results. Multiparameter linear regression (MLR) of log k A versus the solvatochromic parameters demonstrates that the reaction rate constant increases with E N T , π * , and β and decreases with α parameter. To predict accurately solvent effects on the rate constant, optimized artificial neural network with three inputs (including α, π * , and β parameters) was applied for prediction of the log k A values in the prediction set. It was found that properly selected and trained neural network could fairly represent the dependence of the reaction rate constant on solvatochromic parameters. Mean percent deviation of 5.023 for the prediction set by the MLR model should be compared with the value of 0.343 by the artificial neural network model. These improvements are due to the fact that the reaction rate constant shows nonlinear correlations with the solvatochromic parameters. C

Electronic and solvent effects on kinetics of SNAr substitution reactions of substituted anilines with 2,6-bis(trifluoromethanesulfonyl)-4-nitroanisole in MeOH–Me2SO mixtures of varying composition: one reaction with two mechanistic pathways

“…In general, these parameters constitute more comprehensive measures of solvent polarity than the dielectric constant alone, because they reflect more reliably the complete picture of all intermolecular forces acting between solute and solvent molecules. This approach has been widely and successfully applied in the correlation analysis of all kinds of solvent-dependent processes [ 52 – 56 ]. Using the solvatochromic parameters π *, α , and β , where π * is the index of the solvent dipolarity/polarizability, which is a measure of the ability of a solvent to stabilize a charge or a dipole by its own dielectric effects.…”

The “dimer nucleophile mechanism” for reactions with rate‐determining first step: Derivation of the whole kinetic law and further treatment of kinetic results

“…The study of solvent effects in ANS contributes to the understanding of the microscopic properties of solvent due the complex interactions between the amine, the substrate, and/or the intermediate that occur involving the solvent molecules [12][13][14]. Intense research on the differential effects of mixed solvents is also being carried out at present [3, 15,16], and it has been reported that properly selected and trained neural network could fairly represent the dependence of the reaction rate constant on solvatochromic parameters [17]. On the other hand, self-association of amines by hydrogen bonding interactions in nonpolar aprotic solvents is a long known phenomenon [18].…”

Preparation and characterization of SnO2 nanoparticles in aqueous solution of [EMIM][EtSO4] as a low cost ionic liquid using ultrasonic irradiation

“…In continuing our investigations about nanomaterial preparations [46][47][48][49] and RTILs [50][51][52][53][54], the ultrasonic-assisted aqueous room temperature ionic liquid (UARTIL) method was applied for preparation of SnO 2 nanoparticles. For above mentioned reasons, halide-free RTIL, 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO 4 ]), was used in this work [55].…”