The kinetics and the mechanism of the thermal decomposition of bis‐pentafluorosulfurtrioxide (SF₅OOOSF₅)

Abstract

Abstract The thermal decomposition of SF 5 O 3 SF 5 has been investigated between 5 and 25°C. In the presence of sufficient high pressures of O 2 the only products formed are SF 5 O 2 SF 5 and O 2 : The reaction is homogeneous. Its rate is strictly first order with respect to the trioxide pressure and independent of the total pressure of the reaction products and of oxygen above a certain limiting pressure: The experimental results can be explained with the following mechanism: equation image In the presence of O 2 > 100 Torr the concentration of SF 5 is insignificantly small. Therefore reactions (5) and (6) do not have to be considered any more, and steps (2) and (2′) will be of no importance. From reactions (1)–(4) it follows: The numerical value of the factor [1 + ( k ′ 1 2 /2 k 3 k 4 ) 1/2 ] is small. It can be estimated that E 3 ≃ 2 ± 1 kcal; therefore, E – E 1 ≤ 1 kcal, and D = (26 – 1) ± 1.0 kcal.