A new IL-supported diol, 1-(2,3-dihydroxypropyl)-3-methylimidazolium hexafluorophosphate has been synthesized and characterized by Fr-IR, ^1H NMR, ^13C NMR and MS (ESI). Its physical properties such as freezing point, solubility and specific gravity and thermal stability were determined. Synthetic utilities of the resultant diol as a protecting group for aldehydes were also investigated.
The ionic conductivity of the solutions formed from 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) and different molecular solvents (MSs) were measured at 298.15 K. The molar conductivity of the ionic liquids (ILs) increased dramatically with increasing concentration of the MSs. It was found that the molar conductivity of the IL in the solutions studied in this work could be well correlated by the molar conductivity of the neat ILs and the dielectric constant and molar volume of the MSs.
An efficient, environmentally friendly procedure was developed for the condensation of aldehydes/ketones and activated methylene compounds with basic ionic liquid as the catalyst in water. This basic ionic liquid catalyst has a very high activity for Knoevenagel condensation to give the corresponding products in 70%-97% isolated yields under mild conditions. The basic ionic liquid catalyst in aqueous system can be reused for six times without any significant loss of activity.
GAO Guo-hua LU Liang ZOU Ting GAO Jin-bao LIU Ye HE Ming-yuan