AbstractThe very low‐pressure pyrolysis (VLPP) technique has been applied to the pyrolysis of di‐t‐amyl peroxide (DTAP) over the temperature range 523‐633°K. VLPP yields a low‐pressure rate constant,kuniThe conversion ofkunitok∞which must be made to calculate the Arrhenius parameters, is accomplished via the RRKM theory. The transition state model used in the RRKM calculations was based on a transition state model which accurately reproduced the VLPP data for di‐t‐butyl peroxide for which the Arrhenius parameters are well known. For the decomposition of DTAP it was found that logk∞(300°K) = 15.8 ‐ 36.4/θ, where θ = 2.303RT, in kcal/mole, and th