2，6-二甲基哌啶＋水体系临界性质的氘代同位素影响  

Deuterium Isotope Effects on the Critical Behavior of 2,6-Dimethylpiperidine+Water System

作　　者：柴守宁[1] 安学勤[2,3] 王金收[1] 吕和坤[1] 沈伟国[1,2] 

机构地区：[1]兰州大学化学化工学院,兰州730000 [2]华东理工大学化学系,上海200237 [3]南京师范大学,江苏省生物功能材料重点实验室,南京210097

出　　处：《物理化学学报》2009年第5期847-852,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20173024,20603014,20673059);国家教育部基金(105074);上海科学技术委员会项目(0652nm010,08jc1408100)资助

摘　　要：用等体积法分别确定2,6-二甲基哌啶+水和2,6-二甲基哌啶+重水体系的临界组成,并测定各自的临界温度.采用折射率法在较宽温度范围内测定两个体系的温度-折射率(T-n)共存曲线,利用标准曲线法将其转化为温度-摩尔分数(T-x)和温度-体积分数(T-准)共存曲线,求得临界指数β、指前因子B、Wegner校正项因子B1及与共存曲线直径ρd相关的参数.研究结果表明,氘代后,体系低临界温度下降了约3.2K,临界组成和共存曲线形状不变,在近临界点临界指数β仍符合三维伊辛模型(3D-Ising)的理论值(0.327).Critical compositions and critical temperatures of （2,6-dimethylpiperidine＋water） and （2,6-dimethylpiperidine＋ heavy water） were determined. Coexistence curves of （T-n） （T is temperature and n is refractive index） for two systems were determined by the measurements of refractive indices of coexisting phases. Coexistence curves of （T-n） were converted to coexistence curves of （T-x） and （T-φ） （x is mole fraction and φ is volume fraction） through standard curves determined by the measurements of refractive indices at various mole fractions and temperatures. The experimental data were analyzed to obtain critical exponents （β）, critical amplitudes （B）, Wegner correction amplitudes （B1） and parameters for diameters （Pd） of coexistence curves. We found that when H2O was substituted by D2O in the system the low critical temperature decreased by 3.2 K while the critical exponent was also consistent with the threedimensional Ising model （3D-Ising） value （0.327） near the critical point. The critical composition and shape of coexistence curves were almost unchanged.

关 键 词：共存曲线 临界现象 折射率 氘代同位素 

分 类 号：O642[理学—物理化学]