Table 1.
Experimental reaction rate constants (kA, kS and kI) at different temperatures, Arrhenius activation energies (Ea) and pre-exponential factors (A). Ea and A values were obtained by the method of least squares. For [NCO]0/[OH]0 = 0.005, data are taken from [11]. (n.m. = not measured).
| Temperature, K | Alcohol Excess [NCO]0/[OH]0 = 0.005 | Stoichiometric Ratio [NCO]0/[OH]0 = 1 | Isocyanate Excess [NCO]0/[OH]0 = 20 |
|---|---|---|---|
| kA × 105, M–1 s–1 | kS × 105, M–1 s–1 | kI × 105, M–1 s–1 | |
| 303 | n.m. | 1.76 ± 0.18 | 0.52 ± 0.04 |
| 313 | 0.16 ± 0.01 | 3.72 ± 0.32 | 0.91 ± 0.07 |
| 323 | 0.23 ± 0.01 | 7.41 ± 0.60 | 1.55 ± 0.11 |
| 333 | 0.33 ± 0.02 | n.m. | n.m. |
| Ea, kJ mol–1 | 30.4 ± 1.6 | 58.6 ± 6.0 | 44.2 ± 4.5 |
| A, M–1 s–1 | 18.8 ± 1.0 | 234113 ± 23971 | 214.9 ± 21.9 |