An amino acid ionic liquid, [C2mim][Val] (l-methyl-3-ethylimidazolium a-aminoisovaleric acid salt), was prepared by the neutralization method. Using the solution-reaction isoperibol calorimeter, the molar solution enthalpies of ionic liquid [C2Mim][Val], △solHm(w), with known initial mass fractions of water, W2, and with different molalities were determined at 298.15+0.01 K. In terms of standard addition method (SAM) and Archer's method, the standard molar enthalpy of solution for [C2mim][Val] without water, AsolHm, was obtained. The combustion energy of the ionic liquid was determined using an RB-II type the rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion, △cHm, and the standard molar enthalpy of formation, △fHm, were calculated. In terms of standard molar enthalpy of solution, △f Hm, and the standard molar enthalpy of formation for cation of [C2mim]+, the standard molar enthalpy of formation for anion of [Val]- in water solution were calculated. Using an RD496-III heat conduction micro-calorimeter, the molar enthalpies of dilution, △DHm(mi→mf), of aqueous [C2mim][Val] with various molalities were measured. The values of apparent relative molar enthalpy, φL, were calculated using extended De-bye-Hiickel equation, which are in good agreement with that calculated using Pitzer's ion-interaction model.%用中和法合成了氨基酸离子液体1-甲基-3-乙基咪唑缬氨酸盐([C2mim][Val]).在298.15±0.01 K下,利用恒温溶解反应热量计测定了不同含水量的[C2mim][Val]溶解成不同质量摩尔浓度溶液的溶解焓,ΔsolHm(w),借助标准加入法(SAM)和Archer方法得到了无水离子液体[C2mim][Val]的标准摩尔溶解焓,ΔsolHm(Θ).利用RB-Ⅱ型精密转动弹热量计测定了该离子液体的燃烧热,计算了其标准摩尔燃烧焓ΔcHm(Θ)和标准摩尔生成焓ΔfHm(Θ);并结合该离子液体的标准摩尔溶解焓和乙基咪唑阳离子[C2mim]+在水溶液中的标准摩尔生成焓,计算了[Val]-离子在水溶液中的标准摩尔生成焓.利用RD496-Ⅲ型热导式微量热量计测定了不同质量摩尔浓度[C2mim][Val]水溶液的稀释焓,根据扩展的Debye-Hückel方程计算得到的相对表观摩尔焓φL和根据Pitzer离子相互作用模型的计算值在实验误差范围内很好一致.
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