Molar excess enthalpies of binary mixtures of [tributyl phosphate + {CH3(CH2)nOH (n = 0 to 3)}] at 298.15 K

The excess molar enthalpies (HmE) of binary mixtures between tributyl phosphate (TBP) and aliphatic alcohols {CH3(CH2)nOH, (n = 0 to 3)} were measured with a TAM air isothermal calorimeter at 298.15 K and atmospheric pressure. The results of HmE for {xTBP + (1 − x)CH3OH} are negative but positive for {xTBP + (1 − x)C3H7OH} and {xTBP + (1 − x)C4H9OH} in the whole range of composition, while the values of HmE for {xTBP + (1 − x)C2H5OH} change from positive values at low x to small negative values at high x and the curve become S shaped. The experimental results have been correlated with the Redlich–Kister polynomial equation. The excess partial molar enthalpies at infinite dilution were determined for each mixture. IR spectra of the mixtures were measured to investigate the effect of hydrogen bonding in the mixture.