Low pressure carbon dioxide solubility in pure electrolyte solvents for lithium-ion batteries as a function of temperature. Measurement and prediction

Experimental values for the carbon dioxide solubility in eight pure electrolyte solvents for lithium ion batteries – such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ?-butyrolactone (?BL), ethyl acetate (EA) and methyl propionate (MP) – are reported as a function of temperature from (283 to 353) K and atmospheric pressure. Based on experimental solubility data, the Henry’s law constant of the carbon dioxide in these solvents was then deduced and compared with reported values from the literature, as well as with those predicted by using COSMO-RS methodology within COSMOthermX software and those calculated by the Peng–Robinson equation of state implemented into Aspen plus. From this work, it appears that the CO2 solubility is higher in linear carbonates (such as DMC, EMC, DEC) than in cyclic ones (EC, PC, ?BL). Furthermore, the highest CO2 solubility was obtained in MP and EA solvents, which are comparable to the solubility values reported in classical ionicliquids. The precision and accuracy of the experimental values, considered as the per cent of the relative average absolute deviations of the Henry’s law constants from appropriate smoothing equations and from literature values, are close to (1% and 15%), respectively. From the variation of the Henry’s law constants with temperature, the partial molar thermodynamic functions of dissolution such as the standard Gibbs free energy, the enthalpy, and the entropy are calculated, as well as the mixing enthalpy of the solvent with CO2 in its hypothetical liquid state.

Solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon, and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate between temperatures 283 K and 343 K and at pressures close to atmospheric

Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3- methylimidazolium tetrafluoroborate, [bmim][BF4] - a room temperature ionic liquid - are reported as a function of temperature between 283 K and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble gas with mole fraction solubilities of the order of 10-2. Ethane and methane are one order of magnitude more soluble than the other five gases that have mole fraction solubilities of the order of 10-4. Hydrogen is the less soluble of the gaseous solutes studied. From the variation of solubility, expressed as Henry's law constants, with temperature, the partial molar thermodynamic functions of solvation such as the standard Gibbs energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations is of 1%. © 2005 Elsevier Ltd. All rights reserved.

Influence of the cation on the solubility of CO2 and H 2 in ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion

Experimental values for the solubility of carbon dioxide and hydrogen in three room temperature ionic liquids based on the same anion- (bistrifluoromethylsulfonyl)imide [Ntf2]-and three different cations-1-butyl-3-methylimidazolium, [C4mim], 1-ethyl-3- methylimidazolium, [C2mim] and trimethyl-butylammonium, [N 4111]-are reported between 283 and 343 K and close to atmospheric pressure. Carbon dioxide, with a mole-fraction solubility of the order of 10-2, is two orders of magnitude more soluble than hydrogen. The solubility of CO2 is very similar in the three ionic liquids although slightly lower in the presence of the [C2mim] cation. In the case of H2, noticeable differences were observed with larger mole fraction solubilities in the presence of [N4111] followed by [C 4mim]. All of the mole-fraction solubilities decrease with increasing temperature. From the variation of Henry's law constants with temperature, the thermodynamic functions of solvation were calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is always better than ±1%. © Springer Science+Business Media, LLC 2007.

Solubility of carbon dioxide and ethane in three ionic liquids based on the bis{(trifluoromethyl)sulfonyl}imide anion

The objective of this work was to study the influence of changing the cation of the ionic liquid (IL) on gas solubility. For this purpose, the low-pressure solubility of carbon dioxide and of ethane in three ILs based on the bis{(trifluoromethyl)sulfonyl}imide anion ([NTf2](-)) was determined experimentally. Solubility data is reported for 1-ethyl-3-methylimidazolium ([C(1)C(2)Im](+)), 1-butyl-1-methylpyrrolidinium ([C(1)C(4)pyrr](+)) and propylcholinium ([N1132-OH](+)) bis{(trifluoromethyl)sulfonyl}imide ILs between 300 and 345 K. These data are precise to within +/- 1% and accurate to within +/- 5%. In these ILs, carbon dioxide (mole fraction solubility between 1 and 3 x 10(-2), molarity between 0.03 and 0.1 mol L-1) is one order of magnitude more soluble than ethane. The effect of changing the cation is small but significant. Changing the cation has a similar effect on both gases even if the differences are more pronounced in the case of ethane with the order of solubility [C(1)C(4)pyrr][NTf2] > [C(1)C(2)Im][NTf2] > [N1132-OH][NTf2]. For all the systems, the solubility decreases with temperature corresponding to exothermic processes of solvation and negative enthalpies and entropies of solvation were calculated. The properties of solvation of the two gases in [C(1)C(4)pyrr][NTf2] do not vary significantly with temperature while important variations are depicted for both gases in [C(1)C(2)Im][NTf2]. (c) 2007 Elsevier B.V. All rights reserved.

Iron Age Pastoral Nomadism and Agriculture in the Eastern Eurasian Steppe: Implications from Dental Palaeopathology and Stable Carbon and Nitrogen Isotopes

Iron Age societies of the eastern Eurasian steppe are traditionally viewed as nomadic pastoralists. However, recent archaeological and anthropological research in Kazakhstan has reminded us that pastoralist economies can be highly complex and involve agriculture. This paper explores the nature of the pastoralist economies in two Early Iron Age populations from the burial grounds of Ai-Dai and Aymyrlyg in Southern Siberia. These populations represent two cultural groups of the Scythian World - the Tagar Culture of the Minusinsk Basin and the Uyuk Culture of Tuva. Analysis of dental palaeopathology and carbon and nitrogen stable isotopes suggests that domesticated cereals, particularly millet, and fish formed a major component of the diet of both groups. The findings contribute to the emerging picture of the nuances of Early Iron Age subsistence strategies on the eastern steppe.