[deutdeut]

For secondary or tertiary haloalkanes, when they react with weak bases which are wek nucleophiles,which mechanisms, SN1 or E1 generally predominates?

[english]

deutdeut you don't need to make 4 topics on the same thing!  One is enough.

 

[deutdeut]

For tertiary halides, when temperature is low and weak bases are used, SN1predominates, otherwise if temperature is high, say at 60 Celsius, then E predominates. Is it right?

[english]

For tertiary halides, when temperature is low and weak bases are used, SN1predominates, otherwise if temperature is high, say at 60 Celsius, then E predominates. Is it right?

Because tertiary halides to not undergo SN2 reactions, it is safe to assume that they will form almost all SN1 product, under SN1 conditions, so you are correct...but I would think that it would take quite a bit of heat to favor the E1 reaction moreso in this case.

The temperature dependence is only cut and dry for secondary halides, where both SN1/E1 and SN2/E2 reactions are possible.

This means that it's probably difficult to use the temperature as a gauge for tertiary halides to tell if E1 would dominate over SN1 under higher temperature conditions.  I don't know the specific conditions it would take.

[deutdeut]

If I have a secondary halide react with a strong base, E dominates. If the temperature is increased,then does it affect the role that E still dominates?

[Vikas Prajapati]

How does one decide which base is strong enough to give E1 rxns. Generally strong bases r strong nucleophiles also.

[english]

How does one decide which base is strong enough to give E1 rxns. Generally strong bases r strong nucleophiles also.

Strong bases are conjugates of organic acids, especially the alcohols.  Strong bases promote acid-base reactions.

An elimination reaction is not much unlike a weak acid-strong base reaction.

[Vikas Prajapati]

What do you expect if t-butoxide reacts with ethyl chloride? Its a simple wilkinson's synthesis producing an ether. But, nucleophile being a strong and bulky base should give an elemination product also.
My question is:
Which product is major? Does the product change with reaction conditions?

[movies]

What do you expect if t-butoxide reacts with ethyl chloride? Its a simple wilkinson's synthesis producing an ether.

That would be a Williamson ether synthesis, Wilkinson was the organometallic guy (Nobel prize in 1973).