Explore BrainMass

Explore BrainMass

    Why E2 is favored over SN2

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    Sn2 requires a strong nucleophile while E2 requires a strong base. But relatively compared if you have a very strong base the E2 is preferred. Why is it so? Are there any general enthalpy data or something that explains this? I have searched the interenet for a while without finding any mathematical explanation as for example a general difference in enthalpy. And I wanted a that kind of explanation or some other justification. Can anyone help out with that? Some numbers like enthalpy would be great or a explanation in general.

    © BrainMass Inc. brainmass.com October 10, 2019, 7:18 am ad1c9bdddf

    Solution Preview

    You are comparing SN2 vs E2. Let's consider a secondary alkyl halide. The halide can either lose the leaving group and form a carbocation (E1) or the base can pick up the proton along with the leaving group leaving in the same step (E2). A base in organic chemistry is defined by its ability to pick up acidic protons. If a base is strong enough to pick up the acidic proton, then it will do so. If this happens, then the leaving group must leave in ...

    Solution Summary

    An explanation of why E2 is favored over SN2 for secondary alkyl halides is given.