水溶液中L-胱氨酸与氯化镁相互作用的热力学参数

Thermodynamic Parameters of Interaction of L-Cystine with MgCl_2 in Water

在288.15～318.15 K(间隔5 K)下,用分光光度法测定了L-胱氨酸(L-Cystine)在MgCl2水溶液中的溶解度.计算了MgCl2-L-Cystine-H2O体系中L-Cystine的活度系数及盐效应常数kk8,讨论了MgCl2与L-Cystine相互作用的热力学参数.结果表明:ks＜0、gEN＜0、hEN＞0、5EN＞0.应用静电相互作用解释了这些参数及其随温度的变化规律.

Solubilities of L-Cystine in water and series of aqueous solutions of MgCl2at 288.l5~3l8.l5 K are determined by spectrophotomety. The solubilities data are used to calculate the activitycoefficients for L-Cystine and the salting censtant ks for Thermodynamic Parameters-L-Cystine-H2Osystem Thermodynamic Parameters of Pair interaction,gEN、SENand hENbetween MgC12 and L-Cystine inwater.It is shown that ks<0, gEN<0, hEN>0 and sEN>0. The signs of these parameters and thetemperature dependense of them are interpeeted by the electroststic interaction.