Table 1. Values of the thermodynamic parameters obtained from solubility and thermal measurements and lattice energy calculations.
| Hy1A | Hy1B° | Δ (Hy1A – Hy1B°) | |
|---|---|---|---|
| Solubility Measurements (30 – 70 °C, water) | |||
| ΔHsol, kJ mol–1 a | 37.3 | 42.8 | –5.6 |
| ΔSsol, J mol–1 K–1 b | 45.3 | 59.5 | –14.2 |
| Thermal Measurements (55– 100 °C) | |||
| Tfus (°C)c | 111.1 ± 0.2 | 113.1 ± 0.2 | –2.0 ± 0.4 |
| ΔdehyHHy1x-I°d | 53.5 ± 0.3 | 57.1 ± 0.2 | –3.6 ± 0.5 |
| ΔtrsHHy1x-I°e | 11.9 ± 0.2 | 15.4 ± 0.3 | –3.6 ± 0.4 |
| Lattice Energy Calculations (0 K) | |||
| –Elatt (kJ mol–1), CryOpt (PBE0/6-31G(d,p)) | 172.65 | 176.66 | –4.01 |
| –Elatt (kJ mol–1), PBE-TS | 234.45 | 232.48 | –1.97 |
| –Elatt (kJ mol–1), PBE-G06 | 212.13 | 212.80 | –0.73 |
| ΔdehyUHy1x-I°,d PBE- G06 | 79.95 | 80.62 | |
| ΔtrsUHy1x-I°,e PBE- G06 | 20.95 | 21.62 | |
a
Enthalpy of solution, from the slope of van’t Hoff plot (slope = –ΔHsol/R).
b
Entropy of solution, from the constant of the regression line (constant = ΔSsol/R).
c
Melting point (onset temperature).
d
Enthalpy of dehydration.
e
Enthalpy of hydrate to AH I° phase transformation.