Sublimation and vaporization heats of long-chain alcohols

Abstract

The Knudsen method has been used to measure the equilibrium vapour pressures of crystalline and liquid n-alcohols over ranges of temperature. Sublimation and vaporization enthalpies and entropies are reported for the even-carbon homologues c 8 to C22. The essential linearity of AH(sub) with n in C,, leads to the group contributions to this factor and to an estimated H-bond energy in the crystalline alcohols. The influence of temperature, expressed by A C, (crystalline-vapour), is considered. The contribution to the lattice energy of an " unassociated " hydroxyl group is assessed.The enthalpy and entropy terms for the liquid to vapour transformation are similarly determined and show a pattern significant for the structure of the liquid state. By difference, enthalpies and entropies of melting are evaluated and the data checked in terms of " calculated " melting points. The C ~O homologue appears to be anomalous.

Enthalpies and entropies of fusion and of sublimation at the temperature 298.15 K of thiourea and sevenN-alkylthioureas

“…us) for 1-alkanols, (43) and 8.2 kJ · mol −1 and 15.2 J · K −1 · mol −1 for methyl esters. (44) However, the values obtained by averaging all these data, i.e.…”

Evolution of strength and coercivity during annealing of FeCo based alloys

“…It appears that only Davies and Stoloff [14] provide the data required to understand the impact of heat-treatment on strength and coercivity. However, neither…”

“…Davies and Stoloff [14] studied the kinetics of grain growth at temperatures ranging from 675 to 775 • C and reported significantly different behaviour above and below the critical temperature for ordering T c ∼ 720 deg .…”

“…Table 2 lists the grain sizes after 1 h annealing. [14]. * indicates a point which was not measured but extrapolated, the last point for this temperature being for 45 min annealing.…”

“…From the grain sizes reported in table 2, the expected strength and coercivity of the alloy studied by Davies and Stoloff were calculated [14]. Both…”