A Kinetic Study of the Reaction between the 2-Ċ3H7 Radical and i-C4H8: Enthalpy of Formation of the (CH3)2CHCH2Ċ(CH3)2 Radical

Abstract

Abstract The reversible addition reaction 2-Ċ 3H7 + i-C4H8 ⇔ (CH3)2CHCH2 Ċ(CH3)2 was studied in the temperature range 491–543K by product analysis in experiments in which 2-Ċ 3H7 radicals were generated by the thermal decomposition of azoisopropane. The enthalpy of formation of the radical (CH3)2CHCH2 Ċ(CH3)2 was determined, the value obtained being Δf H° = -21.8 ± 5.2kJ mol-1. From this result, the following group value was deduced: Δf H°[Ċ–(C)3] = 177.1kJ mol-1. From the latter, Δf H°(t-Ċ 4H9) = 51.6kJ mol-1 was estimated. The rate constant of self-combination of the radical (CH3)2CHCH2 Ċ(CH3)2 was determined for the first time: log(k 12/(dm3mol-1s-1)) = 7.3.