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Solvent effects on kinetics of an heteroatomic nucleophilic substitution reaction in ionic liquid and molecular solvents mixtures

Salari, H. (Hadi) ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1134/S0036024413120297
  3. Abstract:
  4. Rate constants, k A, for the aromatic nucleophilic substitution reaction of 2-chloro-3,5-dinitropyridine with aniline were determined in different compositions of 2-propanol mixed with hexane, benzene, and 2-methylpropan-2-ol and 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]) with dimethyl sulfoxide at 25°C. The obtained rate constants of the reaction in pure solvents are in the following order: 2-methylpropan-2-ol > dimethyl sulfoxide > 2-propanol > hexane > benzene > [Emim][EtSO4]. Molecularmicroscopic solvent parameters corresponding to the selected binary mixtures were utilized to study the kinetics of a nucleophilic substitution reaction in order to investigate and compare the effects of the solvents on a chemical process. The influence of solvent parameters including normalized polarity (E T N ), dipolarity/polarizability (π*), hydrogen bond donor acidity (α), and hydrogen bond acceptor basicity (β) on the second-order rate constants were investigated and multiple linear regressions gave much better results with regard to single parameter regressions. The dipolarity/polarizability of media has a positive effect in all mixtures regarding zwitterionic character of the reaction intermediate and the hydrogen bond acceptor basicity of the solvent by stabilizing of activated complex increases the reaction rate
  5. Keywords:
  6. Rate constants dipolarity/polarizability of media ; Nucleophilic substitution ; Solvent effects
  7. Source: Russian Journal of Physical Chemistry A ; Volume 87, Issue 12 , December , 2013 , pp 1969-1975 ; 1531-863X
  8. URL: http://link.springer.com/article/10.1134%2FS0036024413120297