Table 5. Effect of Cocatalysts and Oxidants on HMF Conversion and DFF Yield in CH3CNa.
| entry | cocatalyst, loading (mol %) | oxidant | time (h) | conv. HMF (%) | yield DFF (%) | select.b (%) |
|---|---|---|---|---|---|---|
| 1 | TEMPO, 5 | air | 10 | 89 | 88 | 99 |
| 2 | NHPI, 5 | O2 | 24 | 57 | 54 | 95 |
| 3 | DDQ | 10 | 32 | 19 | 59 | |
| 4 | H2O2 | 24 | 11 | 6 | 55 | |
| 5 | TBHP | 24 | 64 | 58 | 91 |
a
Reaction conditions: HMF (1 mmol, 126 mg); Fe(NO3)3·9H2O (0.05 mmol), NaNO2 (0.05 mmol, 3.4 mg), CH3CN (5 mL), and 50 °C; the conversion and yield were determined by HPLC. Conv. = conversion. Select. = selectivity.
b
S (DFF) = yield (DFF)/conversion (HMF).