利用Anton Paar DMA 55精密数字密度计测定了L-丙氨酸在LiNO3,NaNO3,KNO3和NaClO4水溶液中的密度,计算了L-丙氨酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积、理论水化数和体积作用系数.根据静电相互作用和结构水合作用模型讨论...利用Anton Paar DMA 55精密数字密度计测定了L-丙氨酸在LiNO3,NaNO3,KNO3和NaClO4水溶液中的密度,计算了L-丙氨酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积、理论水化数和体积作用系数.根据静电相互作用和结构水合作用模型讨论了阴离子和阳离子对迁移偏摩尔体积的影响.结果表明,L-丙氨酸在四种含氧酸盐水溶液中的迁移体积均为正值,并且随着盐浓度的增大而增大.L-丙氨酸两性离子端基和阴阳离子间的静电作用对迁移体积的贡献是主要的.静电作用削弱了两性离子带电中心对周围水分子的电致收缩效应,造成了理论水化数随溶液浓度的增加而减小.L-丙氨酸在NaNO3,KNO3和NaClO4水溶液中迁移体积的不同主要是由于静电作用的不同引起的,在LiNO3水溶液中迁移体积的“反常”是由于结构相互作用的影响较大所致.展开更多
Enthalpies of solution of L-alanine in water and aqueous solutions of LiNO3,NaNO3,KNO3,（NaClO4） and Na2SO4 were determined at T=298.15 K by a RD496-Ⅱ microcalorimeter.The transfer enthalpies(ΔHtr) of L-alanine fro...Enthalpies of solution of L-alanine in water and aqueous solutions of LiNO3,NaNO3,KNO3,（NaClO4） and Na2SO4 were determined at T=298.15 K by a RD496-Ⅱ microcalorimeter.The transfer enthalpies(ΔHtr) of L-alanine from water to aqueous solutions of salts were derived and discussed in terms of the（electrostatic） interaction and the structural interaction.ΔHtr decreases overall with increasing the concentration of（LiNO3）,NaNO3,KNO3 and NaClO4 but increases with increasing the concentration of Na2SO4.The results show that in LiNO3,NaClO4 and Na2SO4 solutions the structural interaction is responsible for the trends of ΔHtr,while in NaNO3 and KNO3 solutions the effect of electrostatic interaction is predominant. The ion with larger size can make a larger destructive effect on the hydration structure of L-alanine. Anion has more obvious influence on the magnitude of the transfer enthalpy than cation.展开更多
文摘利用Anton Paar DMA 55精密数字密度计测定了L-丙氨酸在LiNO3,NaNO3,KNO3和NaClO4水溶液中的密度,计算了L-丙氨酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积、理论水化数和体积作用系数.根据静电相互作用和结构水合作用模型讨论了阴离子和阳离子对迁移偏摩尔体积的影响.结果表明,L-丙氨酸在四种含氧酸盐水溶液中的迁移体积均为正值,并且随着盐浓度的增大而增大.L-丙氨酸两性离子端基和阴阳离子间的静电作用对迁移体积的贡献是主要的.静电作用削弱了两性离子带电中心对周围水分子的电致收缩效应,造成了理论水化数随溶液浓度的增加而减小.L-丙氨酸在NaNO3,KNO3和NaClO4水溶液中迁移体积的不同主要是由于静电作用的不同引起的,在LiNO3水溶液中迁移体积的“反常”是由于结构相互作用的影响较大所致.
文摘Enthalpies of solution of L-alanine in water and aqueous solutions of LiNO3,NaNO3,KNO3,（NaClO4） and Na2SO4 were determined at T=298.15 K by a RD496-Ⅱ microcalorimeter.The transfer enthalpies(ΔHtr) of L-alanine from water to aqueous solutions of salts were derived and discussed in terms of the（electrostatic） interaction and the structural interaction.ΔHtr decreases overall with increasing the concentration of（LiNO3）,NaNO3,KNO3 and NaClO4 but increases with increasing the concentration of Na2SO4.The results show that in LiNO3,NaClO4 and Na2SO4 solutions the structural interaction is responsible for the trends of ΔHtr,while in NaNO3 and KNO3 solutions the effect of electrostatic interaction is predominant. The ion with larger size can make a larger destructive effect on the hydration structure of L-alanine. Anion has more obvious influence on the magnitude of the transfer enthalpy than cation.
