CHEM 2331H Study Guide - Midterm Guide: Benzoyl Group, Reactive Intermediate, Protonation
Document Summary
General: resonance stabilization is more powerful than substitution stabilization, hso4. But for overall process, needs continuous light supplied, b/c need to make up for loss of radicals from termination steps: propagation itself doesn"t need light b/c breaking + making bonds net energy = 0. Starts and ends w/ radical doesn"t create/destroy electrons. 2nd propagation step consumes product of 1st propagation step, which consumes radical made in 2nd step. Both steps = symbiotic creates cycle/chain chain rxn. 1st step = endothermic, has highest activation energy, but = thermoneutral: overall energy increase = slight. 2nd step = exothermic, activation energy"s lower, product energy"s lowest. 1st transition state > 2nd transition state in energy: termination: 2 radicals combine (can be any combo, alkane + alkane, halogen + halogen, alkane. + halogen); stops chain rxn not very likely b/c amt radicals produced from propagation kept low not as likely to encounter radical as it is to encounter alkene/dihalogen.
