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Topic: Sn1 Vs SN2  (Read 7950 times)

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Offline SciG07

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Sn1 Vs SN2
« on: February 25, 2007, 08:29:12 AM »
Hello.

Im doing coursework on Hydrolysis of Halogenoalkanes.

Im doing 1-ChloroButane, 1-BromoButane, 1-IodoButane.

and ive been told to look at Sn1 Vs sn2 as one of my factors that affect rate of hydrolysis, (using Silver Nitrate to produce a Precipitate...)

And i dont understand how what i can talk about in terms of my experiment.

Offline Yggdrasil

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Re: Sn1 Vs SN2
« Reply #1 on: February 25, 2007, 01:51:29 PM »
Perhaps you could mention which mechanism is involved in the hydrolysis of your particular alkyl halides.  Also, whether the reaction proceeds by an SN1 or SN2 mechanism will affect the kinetics of the reaction, so that may be worth mentioning.

Offline SciG07

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Re: Sn1 Vs SN2
« Reply #2 on: February 26, 2007, 12:11:14 PM »
I think that that my experiment is SN2 am i right. Please reply.

Offline ladygnat

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Re: Sn1 Vs SN2
« Reply #3 on: February 26, 2007, 03:50:16 PM »
I think that that my experiment is SN2 am i right. Please reply.

well, considering your electrophile is primary, your nucleophile is water, right?  I don't see how they could react. 

Water is a really poor nucleophile, even then, if you have a secondary or tertiary haloalkane you'll get an Sn1 reaction.  And of course you'll also get E1 products along with the Sn1 because they compete with following the carbocation.

If your nucleophile isn't water or a strongly basic and hindered nucleophile, then yes, it is an Sn2.   

Offline SciG07

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Re: Sn1 Vs SN2
« Reply #4 on: February 26, 2007, 04:19:26 PM »
Ethanol.

Offline SciG07

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Re: Sn1 Vs SN2
« Reply #5 on: February 26, 2007, 04:21:20 PM »
Also im having difficulties about talking about Hyperconjugation and Inductive effect.

Could you please help... I know what they mean etc, but what can i say about them?

Offline ladygnat

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Re: Sn1 Vs SN2
« Reply #6 on: February 26, 2007, 05:04:18 PM »
Because you aren't using water or any other really poor nucleophile or a really hindered and strong base, and your electrophile is unhindered and primary, it would be Sn2. 

Induction can be talked about with regards to the halogen on your haloalkane.  If it were an Sn1, I would talk about hyperconjugation with regards to the stability of the carbocation. 

Offline wilson

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Re: Sn1 Vs SN2
« Reply #7 on: March 04, 2007, 04:43:29 AM »
Ethanol.
Are you trying to say that you will yield ethanol? But why? If your alkyl group is butyl, shouldn't you be getting butanol?
Just to clarify, are your halobutanes primary, secondary, or tertiary? You've got to know these stuff before you can compare reaction kinetics.

Going back to your first post, you mentioned something like silver nitrate. From what I know, Silver Nitrate producing a precipitate does not affect the rate of reaction. Silver nitrate in ethanol is a qualitative test for SN1 reactions, just like sodium iodide in acetone which is another qualitative test for SN2 reactions.

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