丙氨酸在葡萄糖和蔗糖水溶液中的体积性质

Volumetric Properties of Alanine in Aqueous Glucose and Sucrose Solutions at 298.15 K

利用精密数字密度计分别测定了丙氨酸在不同组成的葡萄糖和蔗糖水溶液中的密度 ,计算了丙氨酸的表观摩尔体积、极限偏摩尔体积和理论水化数 ,根据结构水合作用模型讨论了迁移偏摩尔体积的变化规律 ,并与乙二醇 -水和丙三醇 -水等多羟基体系作了比较 .结果表明 ,丙氨酸分子在多羟基化合物 -水体系中体积效应的大小与多羟基化合物所含 OH基数目有关 .

Densities of L-alanine in aqueous glucose and sucrose solutions were measured at 298.15 K by an oscillating-tube densimeter. Apparent molar volumes V φ, limiting partial molar volumes V 0 φ and number of hydration of alanine N h were calculated. The transfer volumes from water to sugar-water mixtures were obtained and discussed in terms of the structural hydration interaction model. The results obtained were compared with that in glycerol-water and ethylene glycol-water mixtures. It is concluded that the magnitude of enhancement effect on volume is related to the number of OH groups.