Oxidation characteristic and products of ETBE (ethyl tert-butyl ether)

Abstract

The oxidation characteristic of ETBE (ethyl tert-butyl ether) was determined using ARC (accelerating rate calorimetry). Oxidation temperature and oxidation kinetics were calculated using temperature-time (T-t) and pressure-time (P-t) plots, and reaction products were analyzed by GC-MS (gas chromatography-mass spectrum). Results showed that the oxidation reaction process of ETBE with oxygen occurred through absorption of oxygen by ETBE, followed by thermal decomposition and oxidation reaction. The initial auto-oxidation temperature was approximately 383 K. The initial oxygen absorption kinetics was second-order, 1/P = 1.39 × 10−7t + 7.31 × 10−4. The thermal decomposition kinetics of ETBE peroxides was first-order reaction, and parameters were k = Ar × exp (Ea/RT), ln (Ar) = 85.43 (1/min), Ea = 264.9 kJ/mol. Ea was reduced when the reaction included added peroxide. Oxidation reaction products were complex, indicating a link between the products and the ETBE/O2 ratio. Many oxidation products were formed when an excess of oxygen, such as carbon dioxide, formaldehyde, formic acid, or acetic acid was present. And the acetic acid tert-butyl ester and formic acid 1,1-dimethylethyl ester were detected in reaction product. ETBE was stable even 393 K, and exothermic reaction has not been detected even 523 K under a nitrogen atmosphere.