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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: nstack on February 20, 2013, 02:43:53 PM

Title: Organic Chem Sn1 vs E1 Reaction
Post by: nstack on February 20, 2013, 02:43:53 PM
Organic Chem Sn1 vs E1 Reaction


Hello, my professor and I are arguing about a chemical reaction.

Please tell me what the major product would be for: (I attached the image)





Thank you all for your *delete me*
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: Altered State on February 20, 2013, 03:14:31 PM
Heat and a strong base as EtOH bring on Elimination.
I think even without heating those reagents are going to undergo an E1 reaction.

The major product is going to be tert-butyl alcohol anyway
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: Dan on February 20, 2013, 04:32:04 PM
Quote from: Altered State on February 20, 2013, 03:14:31 PM
Heat and a strong base as EtOH bring on Elimination.

Ethanol is not a strong base.

Quote
The major product is going to be tert-butyl alcohol anyway

No it isn't.

Quote from: nstack
Please tell me what the major product

So what's your argument then?

You must show you have attempted the question, this is a Forum Rule (http://www.chemicalforums.com/index.php?topic=65859.0).



Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: Altered State on February 20, 2013, 04:57:42 PM
Quote
Ethanol is not a strong base.

FML, I was thinking of EtO-
We do not have strong base.



Quote
No it isn't.

FML again, I ment elimination product CH2=C(CH3)2
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: nstack on February 20, 2013, 05:45:25 PM
See my image please.
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: orgopete on February 20, 2013, 09:39:26 PM
I should bookmark the page from Reusch's web site. He says it is difficult to control the products and product ratio in an SN1/E1 reaction. I have yet to find anything more accurate.

I expect a mixture. If heated, it will increase elimination. However, HBr is the by-product. I expect it would catalyze protonation of the alkene and catalyze ether formation. The alkene is less basic than the alcohol, so this reaction may be slow. Not only that, but the HBr will also protonate the ether and drive it back toward the alkene. I still say mixture.

A very common ocher lab experiment is the solvolysis of t-butyl halides. I too wondered what the products of this reaction should be. I failed to find a report of the products. I suspect the ratios of alcohol and alkene vary from reaction to reaction.
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: Dan on February 21, 2013, 02:58:44 AM
I agree, undoubtedly a mixture.

If pushed, I'd guess that the ether is the major product due to the vast excess of ethanol.
Title: Re: Organic Chem Sn1 vs E1 Reaction
Post by: Schrödinger on February 21, 2013, 03:53:05 AM
I agree with orgopete. Elimination gives rise to the thermodynamic product and substitution gives rise to the kinetic product. So when you heat the mixture you will invariably get the alkene. Nonetheless, a mixture is inevitable.

Please correct me if I'm wrong.