N,N’-Dialkylimidazolium Dimethyl Phosphates – Promising Media and Catalysts at the Same Time for Condensation Reactions
S. Brica
Faculty of Chemistry, University of Latvia, Riga LV 1585, Latvia
L. Freimane
Faculty of Chemistry, University of Latvia, Riga LV 1585, Latvia
L. Kulikovska
Faculty of Chemistry, University of Latvia, Riga LV 1585, Latvia
A. Zicmanis *
Faculty of Chemistry, University of Latvia, Riga LV 1585, Latvia
*Author to whom correspondence should be addressed.
Abstract
The objective of the current work is the elaboration of an alternative method for synthesis of N,N’-dialkylimidazolium dimethyl phosphates – ionic liquids useful both as media and catalysts for condensation reactions in organic synthesis. The proposed method consists of alkylation of 1-substituted imidazoles with 1-alkyl chlorides in a closed steel cylinder followed by treating of obtained imidazolium chlorides with trimethyl phosphate. Data of qualitative analyses made by 1H NMR, quantitative analysis made by potentiometric titration, and thermal stability measured by thermogravimetry of these elaborated advanced materials are presented. Two successful examples of their use in the Knoevenagel condensation reactions are demonstrated.
Keywords: Ionic liquids, dimethyl phosphate anion, synthesis, condensation reaction