磷酸三甲酯与醇、水混合体系的热力学研究

【作者】 许金凤；

【导师】 刘士军； 刘开宇；

【作者基本信息】 中南大学 ， 物理化学， 2008， 硕士

【摘要】 本文对磷酸三甲酯（TMP）与脂肪醇、水混合体系的热力学性质进行了研究。用TAM Air恒温量热仪测量了{TMP+甲醇/乙醇/正丙醇/正丁醇}及{TMP+水}五个二元体系在298.15 K和常压下的超额混合焓H_m^E,实验结果用Redlich-Kister多元方程进行拟合,并考察了方程各项对体系焓值的贡献。在{TMP+醇}二元系中,实验测定的混合焓值在实验浓度范围内均为正值,即混合过程为吸热效应,焓值变化体现一定的规律性,随着醇类物质碳原子个数的增加,超额混合焓值增大。对于{TMP+甲醇}体系,混合焓的最大值出现在X_TMP=0.30处,而其余三个体系的最大值出现在X_TMP=0.42处,体现了相对较好的对称性。{TMP+水}体系的超额混合焓在不同组成时均为负值,混合过程体现放热效应;混合物的红外光谱表明,TMP与醇分子、水分子之间形成了分子间氢键;对二元混合体系建立了热力学模型,考察了物理作用及化学作用对体系混合焓的贡献。测量了{TMP+水+甲醇/乙醇}三元混合物在298.15K和常压下的超额混合焓H_m^E,采用经验公式对三元体系超额混合焓进行拟合,经最小二乘法求得拟合参数,得到了在298.15K时三元体系超额混合焓H_m,123^E与各组分组成之间的关系,并绘制了三元系的等焓图。更多还原

【Abstract】 The thermodynamic properties of trimethyl phosphate mixed with n-alkanols or water have been investigated in this paper.The excess molar enthalpies of binary mixtures for {Trimethyl Phosphate（TMP） + Methanol/Ethanol/Propan-1-ol/Butan-1-ol} were measured with a TAM Air Isothermal calorimeter at 298.15 K and atmospheric pressure.The experimental results have been correlated with the Redlish-Kister polynomial,and dissociated by the iterations of the Redlish-Kister polynomial.The H_m^E for {xTMP+（1-x）Alkanol} are positive in the whole range of composition,which indiate that the mixing process are endothermic.There is some regularity with the excess molar enthalpies in that the alkanol molecule increases with the number of carbon atom.When the x_（TMP）equals 0.30,the H_m^E value reaches maximum for {xTMP+（1-x）CH3OH},but for the other three systems,the maximum values appear when x_（TMP）=0.42,with a better symmetry.The H_m^E for {xTMP+（1-x）water} are negative in the whole range of composition,indiate that the mixing process are exothermic.IR spectra of the mixtures indicate the existence of hydrogen bonding between TMP and alkanols or water in the mixtures.The thermodynamic model for binary mixtures of {TMP+Methanol/Ethanol/Propan-1-ol/ Butan-1-ol/Water} provides the contributions of physical action and chemistry action.The excess molar enthalpies of ternary mixtures for {x₁TMP+x₂CH₃OH+ （1-x₁-x₂）H₂O} and {x₁TMP+x₂C₂H₅OH+（1-x₁-x₂）H₂O} were measured on the same conditions;The experimental results have been correlated with the experiential equation;Constant H_m.123^E contours at 298.15 K are plotted by using the method of least-squares.更多还原