Electric conductivities of S-alkylisothiouronium salts in nitrobenzene and methanol at 25, 35, and 45�C

Abstract

Conductance data for dilute solutions of S-n-butylisothiouronium bromide and iodide salts as well as S-alkylisothiouronium picrates (alkyl=methyl to octyl) are reported in pure nitrobenzene and methanol at 25, 35, and 45°C. The data were analyzed using Fuoss' equation (1980) (F-80) to obtain the three adjustable parameters; molar conductance at infinite dilution Λo, association constant KA and the association distance R that minimize the standard deviation σΛ. The variation of the parameters for each solvent are discussed with the variation of both cationic and anionic size as well as with temperature. It was found that the solvent-separated ion pair model (SSIP) can be applied in methanol for the salts under investigation. The thermodynamic parameters related to ion-pair formation were calculated and interpreted. The plots of #x039B;o vs. the reciprocal of the molecular weight M were used to separate the molar conductances into values for the individual ions.