硝酸铽与丙氨酸配位反应的热化学研究

Thermochemical study of the coordination reaction of terbium nitrate with alanine

采用具有恒温环境的反应量热计,以溶解量热法,分别测定了298.15 K时[Tb(NO_3)_3·6H_2O(s)+4Ala(s)]和配合物Tb(Ala)_4(NO_3)_3·H_2O(s)在2 mol·L^(-1)HCl溶液中的溶解焓。通过设计的热化学循环,可计算得到六水硝酸铽和丙氨酸配位反应的反应焓△_1H_m~θ(298.15 K)=28.727 kJ·mol^(-1),并计算出配合物Tb(Ala)_4(NO_3)_3·H_2O(s)在298.15 K时的标准生成焓△_1H_m~θ(298.15 K)=-3 847.0 kJ·mol^(-1)。测定了Tb(Ala)_4(NO_3)_3·H_2O(s)在水中的溶解焓,计算出配离子Tb(Ala)_4^(3+)(aq)在298.15 K时的标准生成焓△_1H_m~θ[Tb(Ala)_4^(3+),aq,298.15 K]=-2973.5 kJ·mol^(-1)。

The molar dissolution enthalpies of the [Tb（NO3）3-6H2O（s）＋4Ala（s）] and Tb（Ala）4 （NO3）3·H2O（s） in 2 mol·L^-1 HCl solution have been measured respectively at 298.15 K by classical solution calorimetric. The standard molar reaction enthalpy of the coordination reaction of terbium nitrate with alanine has been determined by a thermochemical cycle, △rHm^θ（298.15K）=28.727kJ·mol^-1. Based on the results, the standard molar enthalpy of formation ofTb（Ala）4（NO3）3·H2O（s） has been calculated to be △fHm^θ（298.15K）=-3847.0kJ·mol^-1. And the molar dissolution enthalpy of Tb（Ala）4（NO3）3·H2O（s） in water has been measured by classical solution calorimeter,and the standard molar formation enthalpy of Tb（Ala）4^3＋（aq）has been calculated at 298.15 K to be△fHm^θ[Tb（Ala）4^3＋,aq,298.15K]=-2973.5kJ·mol^-1.