Volumetric property of glycine, l-serine, l-alanine and l-proline in aqueous solutions of 1-phenylpiperazinium tetrafluoroborate

The densities of aqueous solutions of glycine, l -serine, l -alanine, l -proline with the ionic liquid (IL), 1-phenylpiperazinium tetrafluoroborate ([Phpi][BF 4 ]) at the IL concentrations of (0.025, 0.055 and 0.100) mol·kg −1 have been measured at the temperatures of (298.15, 303.15 and 308.15)   K. On the basis of the experimental results, the apparent molar volume ( V Ф ), standard partial molar volume ( V Ф 0 ), transfer partial molar volume (Δ tr V Φ 0 ) and hydration number ( n H ) have been calculated. The hydrophilic–hydrophilic, hydrophobic–hydrophilic and hydrophobic–hydrophobic interactions are involved in the studied systems of {[Phpi][BF 4 ]   +   amino acids   +   H 2 O. These volumetric parameters can help to understand the mixing effects and other complex biological processes between amino acids and ionic liquid aqueous solution.