This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Chapter 4 Halogenation Addition of halogen to an alkane o Only works on sp 3-hybridized carbons Works best with chlorine and bromine o Iodine is too slow o Fluorine blows up (too fast) Goes through radical intermediate, so putting halogen on more substituted carbon is better o Bromine is way more selective than chlorine Initiation o Homolytic cleavage of X 2 2 Cl Cl Cl 2 Cl Cl Cl o One molecule splits into two radicals Propagation o Start with one molecule and one radical; end up with one molecule and one radical! . + HCl 1) 2) . H Cl Cl Cl Cl Cl + . + HCl 1) 2) . H Cl Cl Cl Cl Cl + Termination o Any two radicals stick together . . . Cl Cl Cl Cl Cl Cl . . . Cl Cl Cl Cl Cl Cl Reactive Intermediates Carbocations o Carbon with three bonds and no lone pairs o Trigonal planar geometry o sp 2-hybridized o empty p-orbital o stability - 3>2>1> methyl o electron-deficient o only intermediate which can undergo rearrangement 1 carbocation with 3 position next door...
View Full Document
This note was uploaded on 03/06/2012 for the course CHEM 301 taught by Professor Sahli during the Spring '07 term at VCU.
- Spring '07