Some features of heat capacity changes in aqueous solutions of low molecular weight alkanols at T = 298.15 K and ambient pressure

•Molar and excess molar heat capacities of aqueous methanol, ethanol, 1-propanol and 2-propanol were derived calorimetrically.•Experimental measurements were carried out at T = 298.15 K and ambient pressure over a composition range to x2 ∼0.36 m.f.•Like molar excess heat capacities, the computed apparent molar heat capacities of the mixture components pass through maxima.•Value of x2 at excess heat capacity maximum is half of a sum of x2 at apparent heat capacity maxima for each mixture studied.•Fact of parity contribution of components of the mixture to structure-energy transformations occurring in it is established. The specific (cp) and molar (Cp) heat capacities of dilute aqueous solutions of methanol (MeOH), ethanol (EtOH), 1-propanol (n-PrOH) and 2-propanol (i-PrOH) were measured using an adiabatic calorimetry at T = 298.15 K and ambient pressure. Based on the obtained results, the excess molar heat capacities, CpE, as well as the apparent molar heat capacities of each of components, Cp,∅,12, of the system {water (1) + alkanol (2)} were calculated. The standard (at infinite dilution) Cp,2o values were also estimated. All the CpE values are positive and pass through maxima, which shift to the range of a lower mole fraction of alcohol, x2, when the molecular weight of the latter increases. The same goes for the Cp,∅,1max values, too. In turn, the order of changing Cp,∅,2max within the narrow high-diluted range of (∼0.01