Sciencemadness Discussion Board

Reduction of Chlorobutanol

guy - 9-12-2006 at 14:46

Can Chlorobutanol be reduced in acid to form tert-butyl-alcohol, similar to how nitro groups are reduced to amines?

HO-C(CH3)2-CCl3 + 3Fe + 3H+ ----> HO-C(CH3)3 + 3Fe2+ + 3Cl-

Shaddy - 13-12-2006 at 13:49

May be, who knows. ;)
At least trichloromethyl group can be reduced with Zinc and HCl.

bbartlog - 29-10-2011 at 15:58

Having just tried this, I can say: not easily, at least not with Fe. Chlorobutanol plus NH4Cl plus Fe, in glycol, yields glop. Actually it yields hydrogen, probably some FeCl2 (based on color), and glop. Probably some sort of amino-glop, since the NH3 from the NH4Cl is still in the flask. Anyway, I would say stick with zinc or (if you have it, since someone else mentioned it in a newer thread) sodium.

AndersHoveland - 7-4-2013 at 07:10

I read that haloalkanes are reduced to the corresponding alkane by reaction with LiAlH4.
I am assuming that the hydroxyl group would not be reduced. Tert-butyl alcohol is much more resistant to reduction than other alcohols, this is in fact the reason that tert-butyl alcohol needs to be used in the reaction to make elemental potassium using magnesium.

Lambda-Eyde - 7-4-2013 at 08:17

Quote: Originally posted by AndersHoveland  
I read that haloalkanes are reduced to the corresponding alkane by reaction with LiAlH4.

What is it with you and not citing sources?

Here:
http://pubs.acs.org/doi/abs/10.1021/ja01191a035
http://pubs.acs.org/doi/abs/10.1021/jo00341a018
Quote: Originally posted by AndersHoveland  
I am assuming that the hydroxyl group would not be reduced. Tert-butyl alcohol is much more resistant to reduction than other alcohols, this is in fact the reason that tert-butyl alcohol needs to be used in the reaction to make elemental potassium using magnesium.

At what point did you elucidate the mechanism by which the synthesis of potassium from KOH+Mg proceeds? AFAIK there's no consensus about that... Also, I fail to see how metallic potassium reduces a primary alcohol such as methanol any more than it reduces tert-butanol. Both will react to give the alkoxide and hydrogen.

chemrox - 7-4-2013 at 19:59

Quote: Originally posted by Shaddy  
May be, who knows. ;)
At least trichloromethyl group can be reduced with Zinc and HCl.


Yes but an unenviable workup follows. Best to find another. H2 + catalyst...

experimenter_ - 26-7-2018 at 01:08

Quote: Originally posted by chemrox  
Quote: Originally posted by Shaddy  
May be, who knows. ;)
At least trichloromethyl group can be reduced with Zinc and HCl.


Yes but an unenviable workup follows. Best to find another. H2 + catalyst...
This is an old thread but potentially useful for people trying to make catalytic potassium ( https://www.sciencemadness.org/whisper/viewthread.php?tid=14... )

May I ask chemrox (or anyone else who knows) what is the "unenviable workup" that follows? Cannot you distill out the tert-butanol or extract with another solvent? (I presume the reaction is performed in aqueous phase?)

experimenter_ - 1-8-2018 at 23:39

One more idea is to dissolve chlorobutanol in a high boiling solvent (e.g. toluene or dioxane), add Mg turnings and then distill the tert-butanol (distills at 82-83).

According to sources, CHCl3 is reduced to methane by Mg metal in neutral pH conditions. CHCl3 is a building block of chlorobutanol, so it is possible that this reduction with Mg will work.

If there is interest about this possible way I could add the links to the sources.