Densities of water solutions in tert-butylamine (t-BuNH2) with the solute molality from ca. (0.015 to 0.35) mol∙(kg solvent)−1 were measured at six temperatures, from T = (278.15 to 303.15) K, and p ∼ 0.1 MPa. The uncertainty in density measurements did not exceed 0.03 kg m−3. The standard (apparent at infinite dilution) molar volumes and expansibilities of water as a solute in t-BuNH2 were calculated. The origins for the phenomenon of the temperature-induced relative partial molar isobaric compaction of a solute (PMICS) in the system under study were discussed based on Ben-Naim’s concept of the “relative affinity parameter”.
