Compilation of enthalpies of sublimation/vaporisation Δgcr,lHom of tri-methoxy-benzenes.
| Compound/CAS | Methoda | T-Range, K | Δgcr,lHom(Tav), kJ mol−1 | Δgcr,lHom(298.15 K)b, kJ mol−1 | Ref. |
|---|---|---|---|---|---|
| 1,2,3-Tri-methoxy-benzene (cr) | DC | 375 | 113.4 ± 0.8 | (98.0 ± 3.2) | 8 |
| T | 288.2–314.3 | 92.3 ± 0.4 | 92.4 ± 0.7 | This work | |
| F | 92.0 ± 0.7 | Table 5 | |||
| 92.2 ± 1.0 c | Average | ||||
| 1,2,3-Tri-methoxy-benzene (liq) | T | 318.1–346.3 | 69.7 ± 0.3 | 73.0 ± 0.5 | This work |
| J x | 72.9 ± 0.5 | Table 3 | |||
| 73.0 ± 0.7 c | Average | ||||
| 1,2,4-Tri-methoxy-benzene (liq) | T | 309.7–350.1 | 72.5 ± 0.3 | 75.7 ± 0.5 | This work |
| J x | 76.0 ± 0.5 | Table 3 | |||
| 75.9 ± 0.7 c | Average | ||||
| 1,3,5-Tri-methoxy-benzene (cr) | DC | 375 | 116.0 ± 1.9 | (100.6 ± 3.6) | 8 |
| T | 288.0–326.2 | 89.9 ± 0.3 | 90.3 ± 0.5 | This work | |
| F | 90.7 ± 0.7 | Table 5 | |||
| 90.4 ± 0.8 c | Average | ||||
| 1,3,5-Tri-methoxy-benzene (liq) | CGC | 298 | 68.2 ± 2.0 | 9 | |
| T | 330.5–375.3 | 63.4 ± 0.2 | 68.7 ± 0.4 | This work | |
| J x | 69.0 ± 1.0 | Table 4 | |||
| 68.7 ± 0.8 c | Average | ||||
| 3,4,5-Tri-methoxy-toluene (liq) | T | 327.2–366.2 | 72.7 ± 0.3 | 77.7 ± 0.5 | This work |
| J x | 77.6 ± 0.5 | Table 3 | |||
| 77.7 ± 0.7 c | Average |
Techniques: DC = drop calorimetry; T = transpiration method; Jx – derived from correlation of experimental vaporisation enthalpies with Kovats's indices (see text); CGC – correlation gas-chromatographic method (see text). F = derived from experimental data according to eqn (6) (see text).
Uncertainties of the vaporisation and sublimation enthalpies is expressed as the standard uncertainty (0.683 level of confidence, k = 1). They were calculated according to a procedure described elsewhere.21,22 Uncertainties include uncertainties from the experimental conditions and the fitting equation, vapor pressures, and uncertainties from adjustment of vaporisation/sublimation enthalpies to the reference temperature T = 298.15 K.
Weighted mean value (the uncertainty was taken as the weighing factor). Uncertainty of the vaporisation/sublimation enthalpy is expressed as the expanded uncertainty (0.95 level of confidence, k = 2). Values in brackets were not included in the averaging. Values highlighted in bold were recommended for thermochemical calculations.