LOW-TEMPERATURE OXIDATION OF MTBE IN A HIGH-PRESSURE JET-STIRRED FLOWREACTOR

Major and minor products of MTBE decomposition and oxidation were meas ured in a jet-stirred flow reactor operated at high pressure near to t he conditions typical of end-gases in spark-ignited engines. Results s howed that the conversion of MTBE was enhanced by the oxidative enviro nment which activates the formation of MTBE radicals, the decompositio n of which leads to the formation of an equimolar mixture of i-C4H8 an d CH3OH. At higher inlet temperatures, also the genuine MTBE oxidation through the classical ''peroxy'' equilibrium typical of the low-tempe rature oxidation of hydrocarbons was observed from both phenomenologic al and chemical point of views. Noticeable heat release and a cool fla me phenomenology were observed up to the complete conversion of MTBE a nd characteristic products of O-2 addition to MTBE redicals were detec ted (heterocyclics and light oxygenated products). However, the larges t part of MTBE is converted by thermal degradation in isobutene which, being a species relatively inert to oxidation, is the cause of the an ti-knock effect of MTBE.