Help! - THH Reduction from Harmala Mix - problem

[merkin]

Hello.

I added just under 200ml vinegar (5%) to what I thought was a pretty clean 8.5g Harmala Mix made from Rue to dissolve and begin stirring. Then this happened: (see pic) whole bunch of yellow froth surged up! I am assuming this was due to base contamination present in the harmala mix? It was some time ago that the mix was made but I think NaOH was used as the base.

Am I screwed or can I recover from this somehow? The froth seems to be dissipating slowly.

(Following Gordotek video)

Thanks!

*edit: froth is pretty much all gone now (stirrer is on), mixture pH is 4.75

 

[downwardsfromzero]

Your surplus NaOH has absorbed CO2 from the air, thereby converting it to a carbonate:

NaOH + CO2 -> NaHCO3

hence the fizzing. Good that you had a tall enough beaker!

 

[merkin]

Oh yeah! I panicked for a bit (it got almost up to the spout) and was very dense foam in the beginning.

So I let it settle, added some more vinegar to get the pH down to 4-ish then filtered three times and kinda started the end of the original extraction step again - but adding Sodium Carbonate this time to base it to pH 10. Now waiting for it to precipitate and then wash with DH2O I guess to get the pH down again. Or is washing with 3% ammonia better?

Hope that was the right action?

Then when its dry I can start over with the zinc reduction and hopefully no more fizz because it should be a lot cleaner now.

I don't need to go through manske again do I? It was done 5 times originally.

 

[blue.magic]

Washing with ammonia is better because there is less chance a tiny bit of your product redissolving in the water.

I don't think Manske is needed, but I would at least redissolve the powder in acetic acid, filter and re-precipitate with ammonia. This way you will remove metal impurities that might have been trapped during the 1st precipitation.