[Teddy]

1. When doing the lab, benzyl chloride reacted under SN1 and SN2 conditions. Since it is a primary alkyl halide, why would it undergo an SN1 mechanism?

2. The bromobenzene in this lab was unreactive under both SN1 and SN2 conditions. Is this related to the bulkiness of the benzene ring? Any other thoughts?

3. Why under SN2 conditions would benzyl chloride react faster than 1-chlorobutane? Both are primary alkyl halides. Does this deal with the reasoning that benzyl cloride is more substituted? If so, why does that even matter?

4. Bromocyclopentane reacted more than bromocylcohexane when heated under SN2 conditions. Is the reaction intermediate more stable? That doesn't make sense to me because an SN2 mechanism is made up of the one step and an intermediate cannot be found in solution.

I am sorry for all the questions, but I do not understand these results. My instructor expects us to figure it out on our own. He did not explain it at all.

[movies]

Show some of your own work on these problems or this thread will be locked.

Please read the forum rules here.

[Teddy]

I think that I figured most of my questions out. I am still having problems with my question number three. I don't think that it has to do with benzyl chloride being more substituted anymore. I think it has to do with the ring.

I know that if I have an activating substituent attached to the benzene ring, the activating energy is lowered so that the reaction proceeds quicker than in ortho etc. To me, this seems to deal more with a carbocation(SN1). Does this have anything to do with it at all? Am I even thinking correctly?

[movies]

You're on the right track.  Think about the transition state for an S_N2 reaction.  What aspects would make you think that a ring would stabilize the transition state relative to the acyclic, aliphatic version?