Thermodynamics of Nitroanisoles: Experimental Vapor Pressures Obtained via a Chromatography-Coupled Transpiration Method of Mono‑, Di‑, and Trinitro-Substituted Anisoles

For the first time, the experimental vapor pressures of the nitroanisole systemwhich has achieved widespread applicationswere measured. The mononitro-substituted 1-methoxy-2-nitrobenzene, 1-methoxy-3-nitrobenzene, and 1-methoxy-4-nitrobenzene as well as the polynitro-substituted 1-methoxy-2,4-dinitrobenzene and 1-methoxy-2,4,6-trinitrobenzene were thermodynamically characterized by the chromatographically assisted transpiration method and differential scanning calorimetry. The resulting p-T fitting equations based on the Clausius–Clapeyron relationship were investigated and utilized to determine the molar sublimation or vaporization enthalpy at the reference temperature of 298.15 K. The results are (76.4 ± 1.5) kJ mol^–1 for 1-methoxy-2-nitrobenzene (l), (85.2 ± 1.6) kJ mol^–1 for 1-methoxy-3-nitrobenzene (cr), (89.6 ± 1.1) kJ mol^–1 for 1-methoxy-4-nitrobenzene (cr), (109.5 ± 0.5) kJ mol^–1 for 1-methoxy-2,4-dinitrobenzene (cr), (92.6 ± 1.6) kJ mol^–1 for 1-methoxy-2,4-dinitrobenzene (l), (118.3 ± 2.2) kJ mol^–1 for 1-methoxy-2,4,6-trinitrobenzene (cr), and (103.5 ± 5.8) kJ mol^–1 for 1-methoxy-2,4,6-trinitrobenzene (l). Furthermore, their p-T fitting equations were used to extrapolate the vapor pressure to 298.15 K, with the corresponding vapor pressure results reported in this work. The results obtained were compared to the existing literature values.