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Topic: When HCl reacts with a tertiary alcohol, why is SN1 the major product?  (Read 3981 times)

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Offline SniperDogs

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When HCl reacts with a tertiary alcohol, why is SN1 the major product?
« on: December 06, 2009, 05:09:32 PM »
Since HCl is not a nucleophile, shouldn't the product be E1?
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Offline baboom

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Re: When HCl reacts with a tertiary alcohol, why is SN1 the major product?
« Reply #1 on: December 06, 2009, 06:05:09 PM »
This is because Cl- is a very very weak base. Also, it is not bulky at all, so it will more readily attack the carbocation, than abstract the hydrgen in an E1 elimination. 
« Last Edit: December 06, 2009, 06:21:58 PM by baboom »
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Offline orgopete

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Re: When HCl reacts with a tertiary alcohol, why is SN1 the major product?
« Reply #2 on: December 06, 2009, 09:57:42 PM »
While it is reasonable to expect some elimination from the carbocation to form, in this case, that reaction is reversible. Since protonation of a 1,1-disubstititued alkene is much easier than mono or unsubstituted alkene(as it reforms the tertiary carbocation), if it does form, it reacts to reform the tertiary carbocation.
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Offline baboom

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Re: When HCl reacts with a tertiary alcohol, why is SN1 the major product?
« Reply #3 on: December 07, 2009, 12:13:29 PM »
HCl is not a nucleophile, but when it is in solution, it completely dissociates into H+ and Cl-. The H+ combines with the oxygen from the alcohol, to make a better leaving group (since HO- is not a good leaving group byitself). Than, Cl- acts as a weak nucelophile.
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