Studies of partial molar volumes of alkylamine in non-electrolyte solvents: I. Alkylamines in hydrocarbons at 303.15 and 313.15 K

Apparent molar volumes Vϕ,B of n-propylamine, n-butylamine, di-n-propylamine, di-n-butylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine in cyclohexane and benzene at 303.15 and 313.15 K have been calculated from the densities ρ determined with high precision vibrating tube densimeter. From these data limiting partial molar volume image and limiting excess partial molar volumes image were estimated. The results are analysed and interpreted in terms of disruption of amine–amine and solute–solvent interactions. The contribution to partial molar volumes of the methyl, methylene, and primary, secondary and tertiary amine groups at 303.15 and 313.15 K in cyclohexane and benzene solutions have been calculated using simple additive scheme. The results were interpreted in terms of conformational effects present in these molecules. An attempt to find a measure of the contribution of the specific interactions to the partial molar volume of primary, secondary and tertiary amines in benzene was made using Teresawa model, hard sphere theory (HST) and scaled particle theory (SPT). The Flory theory/ERAS model has also been applied to estimate apparent molar volumes. The results agree well in the different approaches used.