The high temperature pyrolysis of ethyl tert-butyl ether (ETBE) was studied behind reflected shock waves coupled with the single-pulse; method and UV (195 nm) absorption spectroscopy in the temperature range 1000-1500 K at total pressures ranging between 1.0 and 9.0 atm. The energies of ETBE and transition states for the reactions ETBE = iso-C4H8 + C2H5OH (1) and ETBE = C2H4 + tert-C4H9OH (2) were calculated at the MP4/cc-pVTZ//MP2/cc-pVTZ level of theory. A 170-reaction mechanism was constructed to explain the product distribution. From the UV absorption experiment, the rate coefficient k(1) = 1.7 x 10(14)exp(-254.0 kJ mol(-1)/RT) s(-1) was found to reach its high-pressure limit. (C) 2007 Elsevier B.V. All rights reserved.