Sciencemadness Discussion Board

Reductions with Aluminum / NaOH ?

organosurf - 4-3-2014 at 08:17

Aluminum in aqueous NaOH reacts vigorously and is very exothermic, liberating hydrogen gas.
Final product is highly alkaline. Can this be used in place of aluminum amalgam reductions for basic or neutral reactants for metal surface mediated hydrogenations ?

thesmug - 4-3-2014 at 08:18

May I ask why you need aluminum amalgam?

organosurf - 4-3-2014 at 08:26

I DONT need aluminum amalgam. If you read my post carefully, I wanted to know if there is a green alternative for reductions, a SUBSTITUTE for toxic aluminum amalgam reductions which the university teaching sites on the web mention in their examples on metal mediated reductions.

thesmug - 4-3-2014 at 08:27

What I am asking is what are you doing that would otherwise require aluminum amalgam?

turd - 4-3-2014 at 09:23

Quote: Originally posted by organosurf  
Can this be used in place of aluminum amalgam reductions for basic or neutral reactants for metal surface mediated hydrogenations ?

No - this has been asked many times before and the answer is still - no.
Quote:
What I am asking is what are you doing that would otherwise require aluminum amalgam?

If you have nothing to contribute, simply don't post.

Theoretic - 4-3-2014 at 18:30

Gallium can be used in place of mercury: http://news.uns.purdue.edu/x/2007a/070515WoodallHydrogen.htm...

As far as the hydrogenations are concerned, there are quite a few catalytic H2-using protocols, with new ones appearing all the time. So many such reactions don't need dissolving metal.

papaya - 5-3-2014 at 00:38

I must add that once I managed to obtain isopropanol from acetone by Al/NaOH reduction in water . The mixture was distilled afterwards and used to prepare isopropyl nitrite (with low yield) just to prove that the alcohol really forms. I won't say it's effective since huge amounts of H2 is liberated, but in desperate cases it may be useful.

Mesa - 5-3-2014 at 05:22

Quote: Originally posted by turd  

Quote:
What I am asking is what are you doing that would otherwise require aluminum amalgam?

If you have nothing to contribute, simply don't post.


I don't understand how this is not a legitimate question. Activated aluminium reduces a pretty wide variety of functional groups, without knowing what the starting compound/target compound is, it's difficult to give advice.

Electra - 5-3-2014 at 08:37

Quote: Originally posted by Mesa  
Quote: Originally posted by turd  

Quote:
What I am asking is what are you doing that would otherwise require aluminum amalgam?

If you have nothing to contribute, simply don't post.


I don't understand how this is not a legitimate question. Activated aluminium reduces a pretty wide variety of functional groups, without knowing what the starting compound/target compound is, it's difficult to give advice.


I have to second Mesa here. Depending on the functional group, not all reduction methods are equal.

I don't even know why people do Aluminum Amalgams. So Messy, toxic, and so many other easier and clean ways to perform reductions.

Mesa - 5-3-2014 at 10:24

They are good for drying ethanol, or preparing aluminium isopropoxide, although neither of these are specifically redox's.