Evidence for Structural Transformation in Liquid Octyl Alcohols from PVT Studies

The densities of 2‐ and 3‐octanol and 2‐ and 5‐methyl‐3‐heptanol have been measured over a wide range of temperature and pressure. The isochoric $\mathrm{P–T}$ loci of 2‐ and 3‐octanol show definite inflections; those of the latter two compounds are linear in the range of measurement. The data are discussed in terms of a structural transformation involving H‐bonded linear chains, dimer rings, and monomer and it is proposed that the inflections characterize the transition from chains to rings and monomer. The proposition is supported by reference to dielectric data and the difference between the two sets of compounds is discussed.