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.
