The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Chemistry - Elimination Mechanism - HELP!!!

Alcohol X has the structure (CH3)2 C(OH)CH(CH3)2

What two products are formed when alcohol X is converted into 2,3-dimethylbut-2-ene in the presence of a strong acid?

I know this is an Elimination reaction, I also understand how one of the products are formed due to the hydrogen leaving which creates a double bond between the two carbons. However I do not understand what the other product would be and how it would be formed?
Please help!!!
Reply 1
Avatar for Dylann
Dylann
21
Surely it's just water? The OH and H are eliminated...

Original post by RedSoldiier
Alcohol X has the structure (CH3)2 C(OH)CH(CH3)2

What two products are formed when alcohol X is converted into 2,3-dimethylbut-2-ene in the presence of a strong acid?

I know this is an Elimination reaction, I also understand how one of the products are formed due to the hydrogen leaving which creates a double bond between the two carbons. However I do not understand what the other product would be and how it would be formed?
Please help!!!
The other product would be water, would it not?

You eliminate the OH as there are no OH groups on the final product, 2,3- dimethylbut-2-ene, and a H is also eliminated so you can form the double bond that is present between two Carbon atoms (Carbon can only form 4 bonds so a C would be unable to have a double bond if a H is still present - as that is 5 bonds, not 4)

That leaves you with water :smile: hopefully that makes some sense.
Reply 3
Avatar for RedSoldiier
RedSoldiier
OP
Original post by Dylann
Surely it's just water? The OH and H are eliminated...


oh alright what about this part


name the isomer of 2,3-dimethylbut-2-ene which is also formed in the reaction.
(edited 9 years ago)
Reply 4
Avatar for RedSoldiier
RedSoldiier
OP
Original post by smozsolution
The other product would be water, would it not?

You eliminate the OH as there are no OH groups on the final product, 2,3- dimethylbut-2-ene, and a H is also eliminated so you can form the double bond that is present between two Carbon atoms (Carbon can only form 4 bonds so a C would be unable to have a double bond if a H is still present - as that is 5 bonds, not 4)

That leaves you with water :smile: hopefully that makes some sense.


oh alright what about this part :frown:


name the isomer of 2,3-dimethylbut-2-ene which is also formed in the reaction.
Original post by RedSoldiier
oh alright what about this part :frown:


name the isomer of 2,3-dimethylbut-2-ene which is also formed in the reaction.


Draw out a compound that has the same molecular formula but has a different structure.

Essentially, it's asking for a different compound that has exactly the same number of Carbons and Hydrogens in it but doesn't look like 2,3-dimethylbut-2-ene. I'd start by drawing that out first and then seeing how you can change the structure.
Reply 6
Avatar for RedSoldiier
RedSoldiier
OP
Original post by smozsolution
Draw out a compound that has the same molecular formula but has a different structure.

Essentially, it's asking for a different compound that has exactly the same number of Carbons and Hydrogens in it but doesn't look like 2,3-dimethylbut-2-ene. I'd start by drawing that out first and then seeing how you can change the structure.


hmm i can't seem to change the structure :angry: :mad::mad::mad::mad::mad:
Original post by RedSoldiier
hmm i can't seem to change the structure :angry: :mad::mad::mad::mad::mad:


Try to either moving the methyl groups or the C=C bond around. You essentially want to end up with something that's not 2,3-dimethylbut-2-ene.
Reply 8
Avatar for Dylann
Dylann
21
Original post by RedSoldiier
oh alright what about this part :frown:


name the isomer of 2,3-dimethylbut-2-ene which is also formed in the reaction.



Original post by smozsolution
Draw out a compound that has the same molecular formula but has a different structure.

Essentially, it's asking for a different compound that has exactly the same number of Carbons and Hydrogens in it but doesn't look like 2,3-dimethylbut-2-ene. I'd start by drawing that out first and then seeing how you can change the structure.


It has to also be formed in the reaction, so you can't just draw any old isomer. Think about elimination, the OH must be eliminated as well as a hydrogen on a neighbouring carbon. The OH is on the second carbon. Therefore, it can be eliminated with the hydrogen on carbon number 1 or carbon number 3. Since the question gave us but-2-ene, we know that must have been the hydrogen on carbon 3, since that was why the double bond formed between carbons 2 and 3.

Therefore the other product must be from carbon number 1, and would be called 2,3-dimethylbut-1-ene :smile:
Original post by Dylann
It has to also be formed in the reaction, so you can't just draw any old isomer. Think about elimination, the OH must be eliminated as well as a hydrogen on a neighbouring carbon. The OH is on the second carbon. Therefore, it can be eliminated with the hydrogen on carbon number 1 or carbon number 3. Since the question gave us but-2-ene, we know that must have been the hydrogen on carbon 3, since that was why the double bond formed between carbons 2 and 3.

Therefore the other product must be from carbon number 1, and would be called 2,3-dimethylbut-1-ene :smile:


Thank you for explaining it a little bit better than I did, hopefully both together we've helped OP somewhat :smile:

I'll rep you tomorrow (seen as I've run out for today :frown:) for that too as it's helped my understanding :biggrin:
Reply 10
Avatar for Dylann
Dylann
21
Original post by RedSoldiier
hmm i can't seem to change the structure :angry: :mad::mad::mad::mad::mad:



Original post by smozsolution
Thank you for explaining it a little bit better than I did, hopefully both together we've helped OP somewhat :smile:

I'll rep you tomorrow (seen as I've run out for today :frown:) for that too as it's helped my understanding :biggrin:


Here's a pic, visual representation is probably easier for this type of question...

alcohol to alkene.png
Reply 11
Avatar for RedSoldiier
RedSoldiier
OP
Original post by Dylann
Here's a pic, visual representation is probably easier for this type of question...



oh i drew the structure wrong
thank you so much ! :colondollar:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you