Thermodynamics of vaporization of some alkyladamantanes

The boiling temperature of 1,3-dimethyladamantane was measured by comparati ve ebulliometry over the pressure range 6 < (p/kPa) < 100. The temperature dependencies of saturation vapour pressure and enthalpy of vaporization, an d the normal boiling temperature, T-b = 476.53 K, were derived. The enthalp y of vaporization, Delta H-g(l)m(o) = (49.21 +/- 0.2) Kj (.) mol(-1), was c alorimetrically measured at T = 308.15 K. The experimental and calculated A g,HI, values were found to agree within the error limits. Densities of the liquid phase were measured at the temperatures (293.15, 298.15, and 303.15) K. The experimental vapour pressures of 1,3-dimethyladamantane and of the previously studied 1,3,5-trimethyladamantane were extrapolated to the regio ns of the liquid phases from the triple to the critical temperatures. (C) 2 001 Academic Press.