Authors: A G Vendilo H Rönkkömäki M HannuKuure M Lajunen J Asikkala V G Krasovsky E A Chernikova P Oksman L H J Lajunen T Tuomi K I Popov
Publish Date: 2009/06/18
Volume: 66, Issue: 3-4, Pages: 223-230
Abstract
Thermodynamic data for cesium complexes formation with 18crown6 18C6 L Cs18C6+ in Nbutyl4methylpyridinium tetrafluoroborate BMPyBF4 I in 1butyl3methylimidazolium tetrafluoroborate BMIMBF4 II and in 1butyl3methylimidazolium dicyanamide BMIMNCN2 III were measured with NMR 133Cs technique at 23–50 °C The stability of cesium complex in RTILs is estimated to be in the range between water and DMFA Stability constants for Cs18C6+ are found to decrease as temperature is increasing The following values for lgKCs+L and ΔHCs+L at 23 °C are determined 26 03 −471 kJ/mol RTIL I 2803 −803 kJ/mol RTIL II and 303 008 −472 kJ/mol RTIL III It is demonstrated that enthalpy change promotes complex formation while the corresponding change of entropy is negative and provides decomposition of Cs18C6+The authors would like to thank the Russian Foundation for Basic Research Grant 070800246 and the Academy of Science of Finland for their financial support of the work We also wish to express our gratitude to Päivi Joensuu for assistance in sample analysis
Keywords: