Kinetics and Pressure Effect in the Thermolysis of Liquid Bibenzyl

Article abstract of DOI:10.1021/jo01294a017

The rate of thermolysis of liquid bibenzyl to toluene and stilbene has been measured as a function of temperature and pressure with upper limits of 400 deg C and 1000 atm (101 MPa).The activation parameters are E_act = 63 kcal, S_act = +9 eu, and V_act = +31 mL.They are consistent with a rate-controlling step involving formation of a widely separated pair of benzyl radicals.The V_act is interpreted in the light of cage effects, and the conventional treatment of diffusive separation and recombination of radical pairs as activated process is called into question.