Kinetics of gas-phase decomposition of oxetan and oxetan-2,2-d2

The pressure dependence of the first-order rate coefficient of oxetan and oxetan-2,2-d₂ decomposition has been studied in the pressure range from about 7 kPa down to 0.01 kPa at various temperatures between 673 and 758 K. Experimental data were analyzed using RRKM theory. Interpretation of the fall-off curves lends support to the high-pressure Arrhenius parameters A = 10^15.42s^?1 and E_A = 259.5 kJ/mol derived from measurements made in the pressure-independent range. Decomposition of oxetan is found to occur via biradical intermediates. Data for the kinetic isotope effect were used to derive kinetic parameters for the ring-opening elementary steps in oxetan and oxetan-d₂ decomposition.