Lowering pH in gibran's caapi extract tek

[merkin]

Hi I am (hopefully) approaching the end of following this tek on 100g of yellow caapi vine. Its all been very slow and steady, especially the initial settling but seemingly according to plan.

Now I have an all but crystal clear water with cloudy precipitate, having gone through the add water/siphon/add... cycle 12 times in total so far. The water has gone from golden yellow to the clear it is now (pic).

My only problem is the pH is staying super high (13+) and I think due to me adding too much NaOH after the acidification wash. Having only done this with rue before I was expecting a similar "creamy streaks" reaction as I added the NaOH while stirring. It was only when I stopped stirring that I noticed the liquid wasn't as clear as I had thought and I saw the precipitation clouds forming. I added over 100ml of NaOH at the 5g/50ml proportion - probably close to 150ml total :shock:

Is there a way to speed up the neutralisation/lowering of the pH other than decant/add water or will adding some acid cause everything to redissolve into the liquid again?

 

[downwardsfromzero]

Presumably you are washing with distilled/deionised water, in which case even a small amount of NaOH will push the pH right up, not to mention the freebase alkaloids doing their small share of soaking up protons. Also, deprotonated harmol might have been present in the crystals, again prolonging the pH elevation.

Once you have drained off as much water as possible it shouldn't require excessively much acid to redissolve the freebase.

 

[merkin]

Yes, I am using distilled water.

This step in the gibran2 tek says to repeat the add water/settle/decant until the pH gets between 7-8. I have already done the step converting it to acid once and discarding the black crud. But having done 12 times and seen hardly any change (if any at all) in the pH I was beginning to think something is amiss as gibran2 mentions only a couple of times. It seems at this point like it might take seriously many settle/decant/add water iterations to get the pH down!

Are you suggesting the best way forward would be to redissolve the precipitate by going backwards and repeating the acidification step (adding acid solution) and then redo the basification except this time adding less NaOH rather than trying to bring down the pH of the current state while keeping the solution relatively base (and the precipitate intact)?

 

[merkin]

Okay, after 30 x decant and re-dilute with distilled water I have hardly moved the needle on the pH - Its 10.9-11.3 now and I am going to give up and evaporate to get at the Harmalas now.

What is the safety implication of it being so high pH - is it dangerous to consume or toxic or something? Or should I just stop worrying about it and carry on?

 

[Jagube]

Your alks are contaminated with lye and you probably don't want to consume that.

I'd strain them through a coffee filter, redissolve in a little vinegar and re-base, but using sodium carbonate this time.

 

[nigredo]

A little off topic here, but the picture you have attached may give me some hope. The pictures featured in gibran's post suggest that 64 grams of caapi should yield about 60 mL of precipitate layer. I have easily 5 times that volume of precipitate with 100g of caapi and it cannot be easily observed to be granular as the precipitate in gibran's pictures. You seem to have at least 400 mL in precipitate, yes?

 

[merkin]

Hi nigredo, I am about to upload a lengthy post about this process that I think you will be interested in. Also more pics as my results look very different to gibrans! Especially the colors and consistencies. Yes, there is a boatload of precipitate there, way more stuff than I anticipated. In the pic the 400ml you see is very light and "fluffy" and settles to less than 200ml over 12 hrs, but still quite airy.

I know I must have obviously contaminated stuff and maybe what I need to know now is how to clean it because I have got waaaaay more yield than anyone here has ever mentioned. It must be me that wrong but hopefully someone will be able to help me get to a cleaner product.

@Jagube - I got impatient and did a re-acidifaction round again and carried on from there. I did not use sodium carbonate though so I suspect I need to do some serious cleaning. Please read my other lengthy post about this and I would appreciate input on going further. I have got huge amounts from the bark and it must be wrong!

One quick question though: what pH should one shoot for after the acidification round? My mistake was not waiting long enough to notice the precipitation and adding too much NaOH. I was expecting it to go white like rue does but it didn't do that at all.


See this post for the whole saga: Way Too Much Yield from Caapi!