四元系溶液中溶质间的Gibbs自由能相互作用参数的研究

用气液色谱法测定２９８．１５Ｋ下，有机溶质在尿素＋高氯酸钠＋甲酰胺固定液中的保留参数，用ＭｃＭｉｌｌａｎ－Ｍａｙｅｒ理论，将溶液的势力学过量性质与溶液中粒子间的对相互作用、三相互作用参数相联系，用热力学方法求得该四元体系中溶质的气液色谱保留参数与Ｇｉｂｂｓ自由能相互作用参数的联系，并就溶质间的相互作用及混合溶剂性质的影响进行了讨论。

Studies on the Interaction Parameters of the Excess Gibbs Free Energy Between Solutes in Quanternary Mixture

The retention values of eight organic solutes(i)(benzene,tetrachloromethane,chloroform,dichloromethane,ethyl acetate,tetrahydrofuran,acetone and methyl ethyl ketone)in stationary solution of urea(j)+sodium perchlorate (k)+formamide (s) at 298.15 K have been measured by a gas-liquid chromatographic method(GLC).The McMillan-Mayer's solution theory,in which all the thermodynamic excess properties of multi-component solution can be expressed by a virial expansion,was used to relate the excess Gibbs free energy of the system to a series of pairs,triplet and higher order interaction parameters. An equation for expressing the relationship between the interaction parameters and the specific retention volume(Vg)of GLC was obtained,that RTln Vg(s+j)/Vg(s+j+k)]=2vgikmk+3v2gikkmk+6vgijkmjmk where Vg(s+j)and Vg(s+j+k)are the specific retention volumes of organic solutes (i) in multi-component stationary solution of s+j and s+j+k respectively.gik is the pair interaction parameters between i and k, gikk and gijk are the triplet interaction parameters of i-k-k and i-j-k.The values of gk,gijk and gikk were obtained by fitting the mj,mk and Vg data to the equation given above. Some information about the solute(i)-solute(k) interaction in formamide and the effect of urea on gik have been discussed,For all solutes of i,gik>0,that means the interaction of i and k makes a positive contribution to Gi In the presence of urea,the gik values become more positive than those in the absence of urea,which enhance the salting-out effect on the noneiectrolyte solutes.For the values of triplet interaction parameters,gijk<0,and the contribution of gikk to Gi can be neglected.