Vapor Pressure of Selected Aliphatic Hexanols by Static and Indirect Chromatographic Methods

Vapor pressures of eight aliphatic hexanols ((±)-3-hexanol, CAS RN: 623-37-0; 2-methyl-2-pentanol, CAS RN: 590-36-3; (±)-2-methyl-3-pentanol, CAS RN: 565-67-3; (±)-3-methyl-2-pentanol, CAS RN: 565-60-6; 3-methyl-3-pentanol, CAS RN: 77-74-7; 2,2-dimethyl-1-butanol, CAS RN: 1185-33-7; 2,3-dimethyl-2-butanol, CAS RN: 594-60-5; and (±)-3,3-dimethyl-2-butanol, CAS RN: 464-07-3) were measured by the static method in the temperature range of 233 to 308 K. These data were combined with selected literature vapor pressures and simultaneously correlated with heat capacities in the ideal gaseous state (determined in the framework of this work, since no literature data were available) and liquid heat capacities reported by us previously. The vapor pressures measured for test (p_x) and reference (p_r) compounds were combined with corresponding gas-liquid chromatographic (GLC) adjusted retention times (t') measured in the same temperature region to determine relative activity coefficients at infinite dilution (γrel∞). The linearly extrapolated values of γrel∞ up to 363 K, together with known directly measured p_r values at these temperatures, allow reasonably accurate p_x data to be obtained at extrapolated temperatures. Results were compared with fragmentary literature data. Enthalpies of vaporization derived from the vapor pressures obtained in this work represent a significant contribution to existing databases.