Table 6. Effect of Reaction Temperature on HMF Conversion and DFF Yield in CH₃CN^a.

entry	temperature (°C)	conv. HMF (%)	yield DFF (%)	select.b (%)
1	RT	16	15	94
2	30	57	55	96
3	40	72	69	95
4	50	100	94	94
5	60	54	52	96
6	70	28	27	96

^aReaction conditions: HMF (1 mmol, 126 mg); Fe(NO₃)₃·9H₂O (0.05 mmol), TEMPO (0.05 mmol, 7.8 mg), NaNO₂ (0.05 mmol, 3.4 mg), CH₃CN (5 mL), and oxygen balloon; the conversion and yield were determined by HPLC. Conv. = conversion. Select. = selectivity.

^bS (DFF) = yield (DFF)/conversion (HMF).