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Topic: SH- vs. OH- in reaction with 2-chloropropane  (Read 9919 times)

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Offline THC

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SH- vs. OH- in reaction with 2-chloropropane
« on: January 13, 2009, 01:42:21 PM »
If 2-chloropropane reacts with SH-, will a thiol or an alkene be the resulting product?

And what if 2-chloropropane reacted with OH- instead, what would be the primary product? And how do I know?

Offline playstyles

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #1 on: January 13, 2009, 02:52:47 PM »
is this 1,1-dichloropropane; 1,2-dichloropropane, or 2,2-dicholorpropane?

Offline THC

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #2 on: January 13, 2009, 03:42:52 PM »
is this 1,1-dichloropropane; 1,2-dichloropropane, or 2,2-dicholorpropane?

Just 1-chloropropane and nothing else :)

Offline CopperSmurf

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #3 on: January 17, 2009, 09:09:35 PM »
Sounds like you would get a mixture of the thiol and alkene, but more of the thiol would be my best guess (by Sn1).

if 2-chloropropane reacted with OH- instead, you'd get 2-propanol (Sn1)

Offline macman104

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #4 on: January 17, 2009, 10:01:35 PM »
SH- is not a good base at all (well, I shouldn't say not a good base at all, but certainly not as good as OH-) and is more nucleophilic than the OH-.  I would expect only substitution from the thiol, and depending on what temperature and solvent used, possibly some elimination from the OH-.

Offline nj_bartel

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #5 on: January 17, 2009, 10:33:36 PM »
I'd expect pretty significant elimination with the OH-, via E2, and mostly substitution via SN2 for SH-.  It's hard to say without reaction conditions though.

Offline macman104

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #6 on: January 17, 2009, 10:38:27 PM »
I'd expect pretty significant elimination with the OH-, via E2, and mostly substitution via SN2 for SH-.  It's hard to say without reaction conditions though.
I agree about reaction conditions, especially for the borderline case of a secondary chloride.

Offline Doom91

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Re: SH- vs. OH- in reaction with 2-chloropropane
« Reply #7 on: February 16, 2009, 11:31:37 AM »
it depends on the solvent
for example dimethyl sulphoxide would be polar enough to dissolve the ionic compound  ,it is not protic ,therefore for OH- and SH- , a large percentage of the product would be Substitution products as the nucleophilicity of the chemical species would not be suppressed
 
however if use a polar protic solvent like water, the nucleophilicity of the chemical species OH- and SH- would be suppressed, therefore a majority of the products would be elimination products
       
If assuming the chemical species OH- and SH- are used in the same solvent,SH- would be a comparatively stronger conjugate base of H2S as compared to OH- as a conjugate base of water,this is because as oxygen is more electro-ve than sulphur , the dipole moment btw sulphur and hydrogen would be much smaller than the dipole moment btw oxygen and hydrogen, hence this would cause the -ve charge on S to be less than the -ve charge on O
Therefore,as SH- is more stable than Oh- , the eqm lies more to the right , hence less likely to act as the base, therefore there would be greater % of SN products as compared to the % of substitution products of OH-
   :) hope u will understand my explanation

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