Oxidation characteristics and explosion risk of 2, 5-dimethylfuran at low temperature

The thermal oxidation reaction of 2,5-dimethylfuran (DMF) was investigated using a custom-designed mini closed pressure vessel test (MCPVT) and traced by 1 H nuclear magnetic resonance( 1 H NMR). The oxidation behavior was monitored by-via temperature–time (T-t) and pressure–time (p-t) plots of MCPVT recording. Oxidation products were determined via gas chromatography-mass spectrometry (GC–MS), and the generated peroxide was examined by iodimetry and thin-layer chromatography (TLC), with the thermal decomposition hazard evaluation by differential scanning calorimeter (DSC) and MCPVT. Results show that the DMF oxidation reaction proceeded through initial oxygen absorption at 39.3 °C, followed by an exothermic self-accelerating oxidation at 84.5 °C. DMF could form high level peroxide in auto-oxidation; the decomposition of peroxides would lead to the radical oxidation that the generated ·OH radical mainly attacks on the position 2/5 of DMF with subsequent addition of O 2 initiating ring-opening reaction, in which DMF was firstly converted to cis -3-hexene-2,5-dione, and then produced the trans -3-hexene-2,5-dione with strong photoisomerism. DMF oxidation showed a high level of residue formation, and those solid products contained considerable amount of peroxides with a high thermal hazard; its exothermic onset temperature (T 0 ) and decomposition heat (Q DSC ) of 58.8 °C and 1982.3 J∙g −1 , and the decomposition maximum temperature rising rate (dT/dt) max and maximum of pressure rising rate (dp/dt) max was 9.98 °C∙s −1 and 291 kPa∙s −1 , respectively. Thermal decomposition of those peroxide products could give rise to thermal runaway of DMF oxidation, and further transformed into a detonation possibly.