The System Lithium Nitrate–ethanol–water and Its Component Binary Systems

Abstract

The system lithium nitrate-water has been investigated by thermal analysis and by X-ray powder diffraction studies. No trace of the hemihydrate reported by Donnan and Burt was found. The X-ray powder diffraction pattern of LiN03.3HzO has been obtained.The equilibrium diagram of the system ethanol-water shows an inflection a t -30' C., corresponding to 40 weight per cent ethanol. This is almost certainly a true peritectic point. The formula of the hydrate formed (if there is one) is uncertain but it may be C?H,OH,5HzO.The system lithium nitrate-ethanol could only be studied in dilute solution (of lithium nitrate) and a t temperatures near room temperature, because of high viscosity and extreme supercooling. No evidence for the existence of a solid alcoholate has been obtained.The system lithium nitrate -ethanol -water has been investigated in the form of a series of pseudobinary systems containing water and alcohol ill fixed ratios. No solid alcoholate of lithium nitrate has been found in solutions containing less than 50 weight per cent ethanol. The investigation could not be pushed beyond this alcohol content because of high viscosity and supercooling. INTRODUCTIONThis study was undertaken as a result of work on the conductance of lithium nitrate in a mixed solvent of water and ethanol (1). We think that, as the alcohol content of such a solvent is increased, the solvation of the lithium ion must change, either progressively or suddenly, from a water solvation t o an alcohol solvation, with consequent increase in the effective diameter of the lithium ion. \Ve hoped t o support this view by the isolation of a solid crystalline alcoholate of lithium nitrate, analogous to the water compound LiN03.3H20, but it appears, a s a result of the work here described, that such an alcoholate does not exist, or a t least that it cannot be isolated. Despite the failure of the original aim of this work, much interesting information has resulted, particularly that relating to the important system ethanol-water.The system lithium nitrate -ethanol -water involves the three binary systems lithium nitrate -water, ethanol-water, and lithium nitrate -ethanol. The latter system has not previously been investigated but the first two have been the subjects of several researches.The system LiN0,-H20 was first studied in detail by Donnan and Burt (2). They reported the existence of a congruently melting trihydrate and of a hemihydrate, which decomposed into anhydrous salt and solution a t 61.1' C. Campbell and Kartzmark (3) repeated the dilatometric experiments of Donnan and Burt but were unable to find any evidence for the existence of the supposed hemihydrate; neither did hemihydrate appear in their isothermal study a t 25' C.The system ethanol-water has attracted the attention of many worlcers but much uncertainty has always surrounded it. This system is well ltnown for its anomalous physical behavior, and the large deviations from ideality shown by its physical properties have often been put fonvard as evidence of compound for...

Thermodynamic study of the system (LiCl+LiNO3+H2O)

“…Also presented in figure 1 are the data from the literature [5,[7][8][9]. Generally, our data are in good agreement with those of Campbell in 1958 [9] and quite different from those reported by Donnan [7] and Campbell in 1942 [8].…”

“…Also presented in figure 1 are the data from the literature [5,[7][8][9]. Generally, our data are in good agreement with those of Campbell in 1958 [9] and quite different from those reported by Donnan [7] and Campbell in 1942 [8]. The solubility data of Campbell in 1958 [9] are somewhat scattered and obviously higher than our results at temperatures near 273 K. Based on all of their scattered experimental points Campbell et al drew a liquidus line (see figure 4 in [9]), which also shows negative salt concentration deviation from the scattered points at T = 273 K and is in agreement with our data.…”

Agile Thermal Management STT-RX. Towards High Energy Density, High Conductivity Thermal Energy Storage Composites (PREPRINT)

“…These samples were cooled at a rate of 10 °C/min (or at different cooling rates, as specified in the text). Undercooling was calculated as the difference between the onset of crystallization (as measured by a large deviation in the heat signal from the DSC) and the equilibrium melting temperature of 29.6 °C [4]. These are exacting conditions, and undercooling is expected to be smaller for both slower cooling rates and for larger sample volumes.…”

“…Furthermore, it is very difficult for phase segregation to occur at eutectic compositions, as the two (or more) solid phases typically co-solidify in an inseparable fashion, such that the average local composition also remains constant. In the specific case of the lithium nitrate-water system, stoichiometric LiNO 3 -3H 2 O (56.1 wt% LiNO 3 ) melts congruently (29.6 °C), while eutectic melting between LiNO 3 -3H 2 O and LiNO 3 occurs at ~59 wt% LiNO 3 (27.9 °C) [4].…”

“…This paper describes the recent development of composite materials based on one candidate salt hydrate system, lithium nitrate trihydrate (LiNO 3 -3H 2 O), at the USAF Research Laboratory. Lithium nitrate trihydrate melts at 29.6 °C, and offers double the volumetric energy densities (~0.4 MJ/m 3 ) and double the thermal conductivities (~0.5-0.6 W/m/K) of comparable melting-point paraffins (Table 1) [3][4][5]. Here, we describe approaches to overcoming limitations associated with lithium nitrate trihydrate, but which are generally applicable to other salt hydrate systems.…”