Table 2. Gibbs Free Energies of Activation (ΔG⧧, kcal/mol), Tunneling Corrections (κ), Rate Constants (kapp, M–1 s–1), and Branching Ratios (Γ, %) at 298.15 K for the UA Oxidation by HO• and HOO• Radicals in the Studied Environmentsa.
| water |
pentyl
ethanoate |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| mechanism | ΔG⧧ | κ | kapp | kf | Γ | ΔG⧧ | κ | kapp | Γ | ||
| set-1 | 7.7 | 6.9 | 1.50 × 107 | 1.44 × 107 | 0.2 | ||||||
| Set-2 | 3.9 | 5.7 | 4.10 × 109 | 1.60 × 108 | 1.7 | ||||||
| OH• | HAT | O3 | 17.7 | 18.7 | 1.21 × 101 | 0.0 | |||||
| O7 | 15.3 | 25.8 | 9.63 × 102 | 9.26 × 102 | 0.0 | 17.6 | 19.6 | 1.49 × 101 | 0.0 | ||
| O9 | 15.7 | 28.9 | 5.49 × 102 | 5.28 × 102 | 0.0 | 17.9 | 25.9 | 1.24 × 101 | 0.0 | ||
| C10 | 5.7 | 3.2 | 1.93 × 109 | 1.86 × 109 | 20.2 | 7.1 | 3.5 | 3.50 × 108 | 15.8 | ||
| C12 | 7.2 | 5.9 | 1.00 × 109 | 9.65 × 108 | 10.5 | 9.4 | 5.7 | 1.40 × 107 | 0.6 | ||
| C14 | 8 | 4.8 | 3.15 × 108 | 3.03 × 108 | 3.3 | 10.1 | 4.5 | 3.20 × 106 | 0.1 | ||
| C15 | 8.3 | 5.8 | 2.35 × 108 | 2.25 × 108 | 2.5 | 10.3 | 5.7 | 3.10 × 106 | 0.1 | ||
| RAF | C2 | 8.6 | 1.2 | 1.46 × 107 | 1.40 × 107 | 0.2 | 10.4 | 1.3 | 3.80 × 105 | 0.0 | |
| C3 | 0.0 | 23.1 | 1.5 | 2.10 × 10–4 | 0.0 | ||||||
| C4 | 4 | 1.5 | 2.20 × 109 | 2.11 × 109 | 23 | 6.6 | 1.1 | 1.80 × 108 | 8.1 | ||
| C4′ | 6.6 | 1.1 | 3.22 × 108 | 3.10 × 108 | 3.4 | 7.1 | 0.6 | 4.50 × 107 | 2.0 | ||
| C6 | 7.3 | 1.2 | 1.25 × 108 | 1.20 × 108 | 1.3 | 8.5 | 0.8 | 5.78 × 106 | 0.3 | ||
| C6′ | 9.7 | 1.0 | 9.80 × 105 | 9.41 × 105 | 0.0 | 8.2 | 1.1 | 1.40 × 107 | 0.6 | ||
| C7 | 5.9 | 1.2 | 8.89 × 108 | 8.54 × 108 | 9.3 | 9.3 | 1.2 | 2.10 × 106 | 0.1 | ||
| C8 | 2.7 | 1.0 | 2.30 × 109 | 2.21 × 109 | 24.1 | 4.7 | 1.1 | 1.60 × 109 | 72.1 | ||
| C9 | 8 | 1.1 | 3.47 × 107 | 3.33 × 107 | 0.4 | 10.1 | 1.3 | 6.32 × 105 | 0.0 | ||
| koverall | 9.18×109 | 2.22 × 109 | |||||||||
| OOH• | set-2 | 9.5 | 17.2 | 7.20 × 105 | 2.81×104 | 100 | |||||
The nuclear reorganization energy (λ); kf = f × kapp, (f(H2UA–) = 0.961, f(H2UA2–) = 0.039).