@article { ISI:000264326100007, title = {Dramatic change in viscosities of pure ionic liquids upon addition of molecular solvents}, journal = {Journal of Solution Chemistry}, volume = {38}, number = {5}, year = {2009}, month = {MAY}, pages = {589-600}, publisher = {SPRINGER/PLENUM PUBLISHERS}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Viscosities of binary mixtures of pyridinium based ionic liquids (1-butyl pyridinium tetrafluoroborate, [BP][BF(4)], 1-butyl 3-methyl pyridinium tetrafluoroborate [3-MBP][BF(4)], 1-butyl 4-methyl pyridinium tetrafluoroborate, [4-MBP][BF(4)]), and phosphonium based ionic liquids, (tetrabutyl phosphonium alaninate, [TBP][Ala]; tetrabutyl phosphonium valinate, [TBP][Val]) with the molecular solvents, water, methanol and dichloromethane, have been measured at 298.15 K. A Brookfield ultra-rheometer was employed to measure the reported viscosities. The drop in viscosity in the close vicinity of pure ionic liquid is more prominent in polar solvents like water compared to less polar solvents. The temperature dependence of this observation was also studied for binary mixtures of [4-MBP][BF(4)] with water in range of 298.15-323.15 K. The Vogel-Fulcher-Tamman (VFT) equation was employed to investigate the temperature dependence of the viscosities of pure pyridinium-based ionic liquids in the temperature range from 298.15-323.15 K.

}, keywords = {ionic liquids, Molecular solvents, VFT equations, viscosity}, issn = {0095-9782}, doi = {10.1007/s10953-009-9390-7}, author = {Khupse, Nageshwar D. and Kumar, Anil} } @article { ISI:000279017900002, title = {Ionic liquids: new materials with wide applications}, journal = {Indian Journal of Chemistry Section A-Inorganic Bio-Inorganic Physical Theoretical \& Analytical Chemistry}, volume = {49}, number = {5-6, SI}, year = {2010}, month = {MAY}, pages = {635-648}, publisher = {NATL INST SCIENCE COMMUNICATION-NISCAIR}, address = {DR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIA}, abstract = {

Ionic liquids have emerged as possible substitutes for volatile organic solvents and have found many applications in a variety of research areas. In this review, an effort has been made to discuss the special properties of ionic liquids that render these unique solvent media useful in chemical transformations, electrochemical applications, extractions, etc.

}, keywords = {Chemical processes, Electrochemical devices, ionic liquids, Physicochemical properties, Solvent properties, viscosity}, issn = {0376-4710}, author = {Khupse, Nageshwar D. and Kumar, Anil} } @article { ISI:000275937400001, title = {Solvent-induced viscosity changes in ionic liquids - a review}, journal = {Proceedings of the National Academy of Sciences India Section A-Physical Sciences}, volume = {80}, number = {1}, year = {2010}, month = {JAN}, pages = {1-12}, publisher = {NATL ACAD SCIENCES INDIA}, address = {5 LAJPATRAI RD, ALLAHABAD 211002, INDIA}, abstract = {

The high viscosity of several ionic liquids is an undesirable property for their applications in a variety of chemical reactions and electrochemical devices. Addition of a solvent in an ionic liquid is known to reduce its high viscosity to a great extent. In this review, an attempt has been made to examine the published data on the reduction in viscosities of many ionic liquids upon the addition of molecular solvents, including water. A tentative description has been provided for the drop in viscosities under these conditions. Analysis of the viscosity data with the help of empirical equations has been summarized. This critical review also outlines the future outlook of the required studies that might be useful to those who are interested in using ionic liquids for a variety of applications.

}, keywords = {ionic liquids, solvent, viscosity}, issn = {0369-8203}, author = {Khupse, Nageshwar D. and Kumar, Anil} } @article { ISI:000279017900010, title = {Temperature dependent viscosity of mixtures of ionic liquids at different compositions}, journal = {Indian Journal of Chemistry Section A-Inorganic Bio-Inorganic Physical Theoretical \& Analytical Chemistry}, volume = {49}, number = {5-6, SI}, year = {2010}, month = {MAY}, pages = {727-730}, publisher = {NATL INST SCIENCE COMMUNICATION-NISCAIR}, address = {DR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIA}, abstract = {

This work presents experimental investigations of viscosities of the mixtures of ionic liquids, viz., [bmim][BF(4)] + [bmim][PF(6)] and [hmim][BF(4)] + [hmim][PF(6)] at different temperatures. The temperature dependence of viscosities of these mixtures has been analysed in the light of Vogel-Fulcher-Tammann (VFT) equation with excellent accuracy. The viscosities of the mixtures have been analysed using a simple mixing rule.

}, keywords = {ionic liquids, viscosity}, issn = {0376-4710}, author = {Khupse, Nageshwar D. and Kurolikar, Shabana R. and Kumar, Anil} }