Application of RRKM theory to the unimolecular isomerization of 1,1-dichlorocyclopropane at low pressures

Abstract

The previous work of Parry and Robinson on the thermal isomerization of 1,1-dichlorocyclopropane to 2,3-dichloropropene has been confirmed and extended to initial pressures of 0.2 Torr. First-order rate constants fall off at pressures below 20 Torr and the experimental fall-off curves have been obtained at 359.2°C and 424.4°C.

Theoretical curves have been computed using RRKM theory for several different “rigid” models of the activated complex and these are shown to be virtually identical. As is observed in other cases, the calculated curve is displaced towards lower pressures compared with the experimental curve, in this case by about 0.5 log units. The theoretical curves are in good agreement with the experimental results if a collisional deactivation efficiency of λ= 0.4 is used.