硝酸铬与组氨酸配合行为的相化学与热化学研究

用相平衡方法研究了硝酸铬-组氨酸-水体系在298.15K时的溶度，绘制了体系的相图，发现并制备了文献未报道的一致溶解配合物:Cr(His)(NO3)3·3H2O(A),Cr(His)2(NO3)3·3H2O(B)和Cr(His)3(NO3)3·3H2O(C)，经分析确定了其组成。用微热量计热测定了硝酸铬和组氨酸在水中的反应焓，计算了这些反应的热动力学参数(活化焓、活化熵及活化自由能)、速率常数和动力学能数(活化能、指前因子及反应级数)。

Study on phase chemistry and thermochemistry of coordination of chromium nitrate to histidine

The solubility of Cr(NO3)3-His-H2O system at 298.15K in the entire concentration range has been investigated by phase equilibrium method and the corresponding phase diagram has been constructed. The congruently soluble complexes Cr(His)(NO3)3·3H2O(A), Cr(His)2(NO3)3 ·3H2O(B) and Cr(His)3(NO3)3·3H2O(C) which have not been reported in literature, have been prepared. The compositions of these complexes are determined by chemical analyses and elemental analyses. The enthalpies of reaction of chromium nitrate with histidine in water have been measured by microcalorimeter. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant, three kinetic parameters (the activation energy, the pre-exponential constant and the reaction order) are obtained.