The phase equilibria of high molecular mass 1-alcohols in supercritical propane is measured to investigate the relationship between the phase equilibrium pressure and the number of carbon atoms and by comparison with n-alkanes, to show the effect of the hydroxyl group. Binary phase equilibrium measurements of high molecular mass 1-alcohols (with 10, 12, 16, 18 and 22 carbon atoms) in supercfitical propane are measured between 378 and 408 K for 1-alcohol mass fractions of 0.0175-0.600. Complete solubility below 100 bar, with no region of liquid-liquid immiscibility, is observed and the phase transition pressure increases with increasing number of carbon atoms. By plotting the number of carbon atoms as a function of the phase transition pressure at constant temperature and mass fraction 1-alcohol, a linear relationship is realized. This linear relationship can be used to estimate the phase equilibrium of 1-alcohols with 10-22 carbon atoms in propane. When the measured 1-alcohol-propane data is compared to published n-alkane-propane data it can be seen that the hydroxyl group has the effect of increasing the phase equilibrium pressure of the 1-alcohol in comparison to the n-alkane. (c) 2007 Elsevier B.V. All rights reserved.