000090799 001__ 90799
000090799 005__ 20190527110901.0
000090799 0247_ $$2doi$$a10.1021/ja0619612
000090799 02470 $$2ISI$$a000241157600037
000090799 02470 $$2DAR$$a9427
000090799 037__ $$aARTICLE
000090799 245__ $$aWhy Are Ionic Liquids Liquid? A Simple Explanation Based on Lattice and Solvation Energies
000090799 269__ $$a2006
000090799 260__ $$c2006
000090799 336__ $$aJournal Articles
000090799 520__ $$aWe have developed a simple and quant. explanation for the relatively low melting temps. of ionic liqs. (ILs). The basic concept was to assess the Gibbs free energy of fusion (&Delta;<sub>fus</sub>G) for the process IL(s) -> IL(l), which relates to the m.p. of the IL. This was done using a suitable Born-Fajans-Haber cycle that was closed by the lattice (i.e., IL(s) -> IL(g)) Gibbs energy and the solvation (i.e., IL(g) -> IL(l)) Gibbs energies of the constituent ions in the molten salt. As part of this project we synthesized and detd. accurate m.ps. (by DSC) and dielec. consts. (by dielec. spectroscopy) for 14 ionic liqs. based on four common anions and nine common cations. Lattice free energies (&Delta;<sub>latt</sub>G) were estd. using a combination of Vol. Based Thermodn. (VBT) and quantum chem. calcns. Free energies of solvation (&Delta;<sub>solv</sub>G) of each ion in the bulk molten salt were calcd. using the COSMO solvation model and the exptl. dielec. consts. Under std. ambient conditions (298.15 K and 105 Pa) &Delta;<sub>fus</sub>G&deg; was found to be neg. for all the ILs studied, as expected for liq. samples. Thus, these ILs are liq. under std. ambient conditions because the liq. state is thermodynamically favorable, due to the large size and conformational flexibility of the ions involved, which leads to small lattice enthalpies and large entropy changes that favor melting. This model can be used to predict the melting temps. and dielec. consts. of ILs with good accuracy. A comparison of the predicted vs exptl. m.ps. for nine of the ILs (excluding those where no melting transition was obsd. and two outliers that were not well described by the model) gave a std. error of the est. (s<sub>est</sub>) of 8 &deg;C. A similar comparison for dielec. const. predictions gave s<sub>est</sub> as 2.5 units. Thus, from very little exptl. and computational data it is possible to predict fundamental properties such as m.ps. and dielec. consts. of ionic liqs.
000090799 700__ $$aKrossing, I
000090799 700__ $$aSlattery, JM
000090799 700__ $$0240582$$g114407$$aDaguenet, C
000090799 700__ $$0240015$$g149418$$aDyson, PJ
000090799 700__ $$aOleinikova, A
000090799 700__ $$aWeingaertner, H.
000090799 773__ $$j128$$tJournal of the American Chemical Society$$k41$$q13427-13434
000090799 8564_ $$uhttps://infoscience.epfl.ch/record/90799/files/ja0619612.pdf$$zn/a$$s174798
000090799 909C0 $$xU9$$0252010$$pLCOM
000090799 909CO $$ooai:infoscience.tind.io:90799$$qGLOBAL_SET$$pSB$$particle
000090799 937__ $$aLCOM-ARTICLE-2006-033
000090799 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000090799 980__ $$aARTICLE