氨基酸-醇-水体系的密度与表观摩尔体积  

Densities and Apparent Molar Volumes of Amino Acids-Alcohol-Water System

作　　者：王秀芳[1] 田勇[1] 卢雁[2] 

机构地区：[1]广东药学院药科学院广州大学城,广州510006 [2]河南师范大学化学与环境科学学院,河南新乡453002

出　　处：《化学学报》2009年第8期716-722,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.50802017)资助项目

摘　　要：用DMA602/60型震动管数字密度计测定了298.15K下甘氨酸、丙氨酸分别在纯水和四个不同浓度甲醇、乙醇和丙醇水溶液中的密度,计算了相应的表观摩尔体积,用最小二乘法拟合了氨基酸在醇水溶液中的标准偏摩尔体积.根据McMillan-Mayer理论拟合了水溶液中氨基酸分别与醇相互作用的对相互作用参数Vab和三相互作用参数Vabb,Vaab.结果表明甘氨酸、丙氨酸在醇水溶液中的表观摩尔体积都随醇浓度的增加而增加,都属亲水破坏性溶质;其自相互作用参数和三相互作用参数均为正值,对相互作用参数Vab均为负值且随烃基链的延长,负值依次增大.分别根据极性分子的相互作用模型、结构水化模型和溶剂分离缔合模型进行了讨论.By using a vitrating digital densimeter （DMA602/60）, the densities of glycine and alanine in aqueous methanol, ethanol and propanol solutions were measured at 298.15 K, and the apparent molar volumes calculated. According to McMillan-Mayer approach, the volumetric interaction coefficients were evaluated. The results show that the apparent molar volumes of glycine and alanine in aqueous alkan-1-ol solutions increase with increasing the alkan-1-ol concentration, which demonstrates that glycine and alanine can be classified as hydrophilic ‘structure-breaking＇ solute. The homoactic interaction coefficients （Vab） and the triplet interaction coefficients （Vabb and Vaab） of glycine and alanine are all positive. The values of the volumetric pair interaction coefficients of amino acids and amides with alkan-1-ols are all negative and the negative values increase with increasing the alkyl chains. It was discussed in terms of a structural hydration model and a solvent separated association pattern.

关 键 词：氨基酸 醇 密度 表观摩尔体积 

分 类 号：O621.2[理学—有机化学]