[Skybydo]

I often see sodium used as a substance to introduce for example N3, an azide or phenol, so that it forms an salt in between and than react easier or at all. Can you also use other alkali metals like lithium and potassium instead? Is it practicable?

[Honclbrif]

Are you asking about counter ions? Azide is an anion, so you need a cation present to balance the charge.

The short answer is yes, as long as the pKa's and redox potentials are compatible, you can make a salt from nearly any two ions of your choosing. However, different cations can have drastic effects on the reactivity of their counter ions. For instance, sodium borohydride is widely known as a mild reducing agent selective for ketones and aldehydes, but lithium borohydride will reduce esters to alcohols.

[Skybydo]

I see, thanks!

[Honclbrif]

I meant to post some other examples but had to run and catch a bus. Another good one to consider is fluoride. Its reactivity changes drastically depending on the counter ion. If you care to, look up the uses of potassium fluoride, cesium fluoride, tetrabutylammonium fluoride, and silver fluoride.

[408]

I have used lithium azide.  far more soluble than sodium in acetonitrile. 

[discodermolide]

I have used lithium azide.  far more soluble than sodium in acetonitrile.  

Try Potassium or Caesium salts, they are much softer  than Na or Li.

[nox]

Counter ion effects can be wildly unpredictable. This C-H activation reaction I'm working on completely shuts down if you switch potassium carbonate for sodium carbonate.

[408]

I have used lithium azide.  far more soluble than sodium in acetonitrile.  

Try Potassium or Caesium salts, they are much softer  than Na or Li.

cesium azide is so deliquescent....  I hate it, because I am too lazy for glove box work.  lithium azide works well after drying under hivac.  But only small scale.  the stuff is crazy-explosive.  No appreciable DDT lag time in flame.  Kevlar gloves and body armour mandatory for dry LiN3

[Honclbrif]

When it comes to azide I stick to sodium. Its one of those things that always has me a little on edge. However, I was stupid enough at one point to make about a gram, neat, of 3-azido-1-amino propane (woooo more nitrogen than carbon!) but still have all my limbs and skin, so maybe I'm just being a big baby. Or stupid lucky. Probably a bit of both.

[discodermolide]

When it comes to azide I stick to sodium. Its one of those things that always has me a little on edge. However, I was stupid enough at one point to make about a gram, neat, of 3-azido-1-amino propane (woooo more nitrogen than carbon!) but still have all my limbs and skin, so maybe I'm just being a big baby. Or stupid lucky. Probably a bit of both.

I have used sodium azide on muli-kilo scale>100kg per batch. It's not a problem if you do the risk analysis and your job correctly and have the correct equipment. In the bottle or drum there is an overpressure of HN3 which is a CNS depressant so don't inhale it otherwise you may faint.

[408]

I was stupid enough at one point to make about a gram, neat, of 3-azido-1-amino propane (woooo more nitrogen than carbon!) but still have all my limbs and skin, so maybe I'm just being a big baby. Or stupid lucky. Probably a bit of both.

Maybe more the first one   I would not expect handling issues for that compound, sensitive explosive yes, but with proper precautions (avoiding impact and friction, no metal spatula in glass flask, etc) it should be fine.  I have made pure dry azidotetrazole on 1 gram scale more times than I can or want to remember, so I acknowledge I am really desensitized to the handling of all but the most sensitive explosives....