Experimental and computational study on the molecular energetics of the three monofluoroanisole isomers

The standard (p∘ = 0.1 MPa) molar enthalpies of formation in the liquid phase of three isomers of fluoroanisole were derived from the standard molar energies of combustion, in oxygen, to yield CO2(g) and HF · 10H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vaporization of these compounds, also at T = 298.15 K, were determined using Calvet microcalorimetry.-ΔcUm∘(l)/(kJ·mol-1)-ΔfHm∘(l)/(kJ·mol-1)ΔlgHm∘/(kJ·mol-1)2-Fluoroanisole3629.7 ± 1.0301.9 ± 1.552.2 ± 1.13- Fluoroanisole3617.1 ± 1.1314.5 ± 1.648.1 ± 1.14- Fluoroanisole3622.4 ± 1.2309.2 ± 1.648.7 ± 1.1Full-size tableTable optionsView in workspaceDownload as CSVThe standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were derived from the former two experimental quantities. These values are also compared with estimates based on two different methodologies: one using the empirical scheme developed by Cox and the other one based on high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311++G(d,p) basis set. The computed values and the estimated values using the Cox method compare well with the experimental results obtained in this work.