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

Abstract

The thermal oxidation reaction of 2,5-dimethylfuran (DMF) was investigated using a custom-designed mini closed pressure vessel test (MCPVT) and traced by 1H nuclear magnetic resonance(1H 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 O2 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 (T0) and decomposition heat (QDSC) 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.