水合烟酸铜Cu(Nic)2•H2O(s)(Nic＝烟酸)的合成、表征及热力学性质

近几十年来,烟酸盐类化合物或配合物由于优越的吸收率高和无毒副作用等特点使其在化妆品、药品和食品等领域作为营养添加剂具有重要应用前景。然而,这类化合物的基础热力学数据极其缺乏,从而限制了这类化合物的理论研究和应用开发的深入开展。为此,本论文利用室温固相合成方法和球磨技术合成了一种新化合物Cu(Nic)2•H2O(s),利用化学分析、元素分析、FTIR和X-射线粉末衍射技术表征了它的结构和组成,利用精密自动绝热热量计准确地测量了它在78-400 K温区的摩尔热容。在热容曲线的T ＝ 326-346 K温区观察到一个明显的固-液相变过程。利用相变温区三次重复实验热容的测量结果确定了此相变过程的峰温、相变焓和相变熵分别为：Tfus＝(341.290 ±0.873) K, DfusHm＝(13.582±0.012) kJ×mol-1, DfusSm＝(39.797±0.067) J×K-1×mol-1。通过最小二乘法将相变前和相变后的热容实验值分别拟合成了热容对温度的两个多项式方程。通过热容多项式方程的数值积分,得到了这个化合物的舒平热容值和相对于298.15 K的各种热力学函数值,并且将每隔5 K的热力学函数值列成了表格。

Synthesis,Characterization, and Thermodynamic Study of the Solid State Coordination Compound Cu(Nic)2·H2O(s)

A novel compound–monohydrated cupric nicotinate was synthesized by the method of room temperature solid phase reaction and a ball grinder. FTIR, chemical and elemental analyses and X‐ray powder diffraction techniques were applied to characterize the structure and composition of the complex. Low‐temperature heat capacities of the solid coordination compound have been measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A melting process occurred in the temperature range of 326–346 K in the heat capacity curve, and the melting point, molar enthalpy and entropy of the fusion were determined to be T_fus= (341.290±0.873) K, Δ_fusH_m= (13.582±0.012) kJ·mol^?1, Δ_fusS_m= (39.797±0.067) J·K^?1·mol^?1. The experimental values of the molar heat capacities in the temperature regions of 78–326 K and 346–400 K were respectively fitted to two polynomial equations. The polynomially fitted values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at an interval of 5 K.