Speed of sound, density, and heat capacity for (2-methyl-2-butanol + heptane) at pressures up to 100 MPa and temperatures from (293 to 318) K. Experimental results and theoretical investigations

In this paper, some new physicochemical properties of (2-methyl-2-butanol + heptane) are investigated using an acoustic method. Of clear interest to us is the study of the effect of branched structure of alcohol on association in mixtures with heptane and consequently, the effect of temperature and pressure on deviations from ideal solution behaviour. Thus, this work presents experimental properties and theoretical study of (2-methyl-2-butanol + heptane) as functions of temperature and pressure over the entire composition range. The densities and speeds of sound in (2-methyl-2-butanol + heptane) have been measured for temperatures ranging from (293 to 318) K under atmospheric pressure and under elevated pressures up to 101 MPa, respectively. The densities, heat capacities and appropriate excesses of these binaries were calculated for the same temperatures and for pressures up to 100 MPa. The acoustic method was applied in the calculations. The effects of pressure and temperature on the excess molar volume and the excess molar heat capacity of (2-methyl-2-butanol + heptane) are explained in terms of the influence of the molecular size and configuration of the alcohols on their self-association capability, packing effect, and the non-specific interactions between the 2-methyl-2-butanol and heptane basing on the results obtained from the modified ERAS model.