[mizna.z]

Two different radicals can be produced when an initiator radical adds to styrene- a primary radical and a secondary radical.
Would the secondary radical be more stable due to something called hyperconjugation?
If so, then why do they http://www.meta-synthesis.com/webbook/14_radical/radical.html show it as a primary one?
(scroll to the near bottom of the link above).-see attached pic

[orgopete]

You are correct about the secondary (and benzylic) radical being more stable. I believe the Chemogenesis reference is in error.

[ufalynn88]

a secondary radical would definitely be more stable than a primary...and tertiary (then allylic, and then benzylic even more stable than that...)...a carbon with a radical present is highly unstable and electrophilic...the presence of neighboring carbons push some electron density onto the radical...thus, the more carbons donating this density in, the more stable =)