Cage Effects in the Thermal Decomposition of 1,1'-Azocyanocyclohexane and the Related Ketenimine

Author: Waits, Harold Paul

Year: 1964

Degree: Dissertation (Ph.D.)

Advisor: Hammond, George Simms

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/W1JH-1892

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

The thermal decompositions of 1,1'-azocyanocyclohexane and the related N-(l-cyanocyclohexyl)-pentamethyleneketenimine were carried out in chlorobenzene solutions containing varying amounts of scavengers. Bromine and iodine were used to scavenge cyanocyclohexyl radicals from the decomposition of the azo compound and DPPH was similarly used in the case of the ketenimine. The stable 1,1'-dicyanobicyclohexyl is a main product in both decompositions and its formation is taken as a measure of the extent of geminate recombination. The decrease in its yield observed at high scavenger concentrations (>0.1 [...]) is attributed to scavenging of caged radicals. The dependence of the decrease in yield on scavenger concentration indicates that secondary recombination is unimportant. Whereas theory predicts a dependence on the square root of the scavenger concentration, a linear relation is observed. It is concluded that interference, by scavenger, with primary recombination can occur only if the scavenger molecule is a nearest neighbor to the radical pair at the time of its formation.

Files