Organic Chem question

[E. coli]

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This one is from DAT achiever:

Which of the following alkyl bromides exhibits SLOWEST rate of E1 elimination?

A. (CH3CH2)2CHBr
B. (CH3)2CHBr
C. (CH3)3CBr
D. CH3CH2CH2Br
E. CH3Br

The answer is E. However, I thought the answer could be D because there is no elimination 1 reaction for E, as there is only one carbon. On the other hand, D is a primary halide, and elimination 1 would be possible at the slowest rate among the other choices.

I don't get how E could have the slowest rate when there is no elimination reaction at all.

 

[heshyn2000]

This one is from DAT achiever:

Which of the following alkyl bromides exhibits SLOWEST rate of E1 elimination?

A. (CH3CH2)2CHBr
B. (CH3)2CHBr
C. (CH3)3CBr
D. CH3CH2CH2Br
E. CH3Br

The answer is E. However, I thought the answer could be D because there is no elimination 1 reaction for E, as there is only one carbon. On the other hand, D is a primary halide, and elimination 1 would be possible at the slowest rate among the other choices.

I don't get how E could have the slowest rate when there is no elimination reaction at all.

Well actually there is, with an extremly stron base, for example (CH3)3O-

 

[mitshi]

In the presence of strong base, E2 predominates over E1. Essentially, both E1 and E2 may co-proceed (with one being faster than the other) on all of the alkyl bromides given depending on the condition of reaction chosen. Note that the question here is simply asking for a straight comparison among the five reactants on E1. It's good to always lead one problem (when reviewing your answers) to another related issue -- an effort that will often end up enhancing your knowledge base; but try not to complicate yourself in the like manner under the exam mode.

Press on still and persevere unceasingly, and I'm sure you guys are going to do well on the real tests. 🙂

 

[mikester2]

Well actually there is, with an extremly stron base, for example (CH3)3O-

What would be the product of this E1 rxn for bromomethyl? I never knew it could even happen.