How much zinc is that for, say, a 100 mg of harmaline? 50 milligrams? A gram? Quarter the volume of solvent?

Thanks for any advice on how much "excess" actually is. I have about 250 grams of zinc dust but I don't want to unnecessarily spoil any.

As for filtering the zinc dust, I would use standard vacuum filtering with glass micro fiber and bed of Celite, which is okay right? (the "Celite" I use is simply a food-grade DE)

2.5 Conversion of DHH freebase to THH
2002mg of DHH was dissolved in 100ml of acetic acid 7%. To this solution, 3008mg zinc
powder was added. This mixture was left to stand at room temperature for several hours under
regular stirring. It was observed under UV-light that the solution's fluorescent color changed
from yellow-green to deep blue in the course of 3 hours. The mixture was left to react for an
additional 6 hours. Then it was filtered giving residue RA1 and the recipient was washed with
water that was poured over the unreacted zinc in the filter and was thereby added to the filtrate.
This brought the total volume of filtrate to 200ml.
Under continuous pH-measurement, a solution of ammonia 12% was added dropwise. The
starting pH was 3,88. When the pH reached 5,42 after adding 16ml of base, a very fine mist
appeared in the solution that did not augment during the further addition of base. At pH 7,25
(21,5ml of ammonia added in total), the solution was filtered again to give residue RA2.
More ammonia was added and after the total addition of 33ml of ammonia 12% (pH 8,77),
clouding once again appeared in the solution and the pH declined steadily to 8,62. At this point
the solution was filtered again and precipitate RA3 was obtained.
The addition of ammonia was continued, but no more clouding nor pH-depression was observed
up to a pH of 9,64. At that moment, 4ml of ammonia 12% were added that gave rise to clouding
at a pH of 9,76. The solution was filtered again to give residue RA4.
A small amount of RA4 was then sublimated at 1mbar and 130°C to give RA5. Another amount
of RA4 was recrystallized twice from ethanol 96% giving RA6.
Then an excess (20ml) of ammonia 12% solution was added that brought the pH to 10,02. No
precipitate formed.
The melting ranges of three consecutive samples of each residue were measured using a Thiele
tube. These results were averaged and rounded to the nearest half degree.

As Mindlusion said, it seems to have worked well. And indeed do with lesser concentration of the sample, will prob help separating the spots better.
......
What surprised me is using acetone to dissolve the harmalas. How much acetone did you use ? How many pulls?

What solvent mixture did you use in TLC?

Could you elaborate more on the details of your conversion?
E.g. how long did you stir? How much vinegar?
Anhydrous acetone, right?
Anything heated?
etc.

Another approach worth trying (and this is where I'd put my money) would be to first use any available base to precipitate the zinc salts and THH freebase, then collect precipitates and retrieve THH with vinegar or better carbonated water; All the zincs will remain insoluble and be left behind while THH will be collected as its acetate or carbonate salt, ready to be re-precipitated with base.

If the zincs are insoluble in vinegar, why weren't they discarded in the "filter out excess zinc" stage after the reduction? Everything that made it to the basic soup should still dissolve in vinegar, otherwise it wouldn't have made it that far, no?

As for carbonated water, is it the stuff sold as sparkling water at grocery stores that some people for some reason drink?

Zinc carbonate is soluble in dilute acids, alkalies and in ammonium salt solutions. It is insoluble in water, ammonia, pyridine, alcohol and acetone.

I remember reading that post-reduction zinc compounds dissolve in ammonia before the THH precipitates, but if your THH contains harmine which you want to recover, it makes things more complicated as the zinc compounds precipitate roughly at the same pH as harmine, and don't dissolve until more ammonia is added.

However, what are the consequences of this (http://www.npi.gov.au/resource/zinc-and-compounds)?:


It says soluble in alkalies (bases), but not in ammonia, which is a base...

Also what about the potential cadmium contamination of zinc? I remember someone saying they probably behave the same way as zinc as far as solubility goes. Do we have a confirmation of this?

The more recent thread Harmine, harmaline and THH from Syrian Rue. Verification and finetuning of the VDS-protocols has much more up-to-date info, but much of it is about harmine/DHH separation.

So therefore using sodium carbonate as a base to precipitate THH seems safer than ammonia assuming THH is synthesized from isolated DHH, not from the mix.

On the other hand when you base it with sodium carbonate, you get zinc carbonate and sodium zincate (?). The quote I posted implies that at least the former should stay in solution.

I fail to see why it would be so? And is it still true when there are no carbonate salts to begin with in the post-reduction solution?

Normally if your alks are pure and distilled water was used, your solution contains zinc, zinc acetate, THH, and possibly cadmium compounds. There is no zinc carbonate.

Aqueous ammonia reacts with cadmium ion to precipitate white cadmium hydroxide, which dissolves in excess ammonia [..]

[quote]Sodium hydroxide produces a precipitate of Cd(OH)2, but the precipitate does not dissolve in excess hydroxide

Aqueous ammonia reacts with cadmium ion to precipitate white cadmium hydroxide, which dissolves in excess ammonia [..]



Does this mean using ammonia for freebasing solves the potential cadmium contamination issue, as long as enough ammonia is used?

Downwardsfromzero is right on the mark. Don't let any toxic metals get into the mix, so you don't need to get them out again.

If you cannot find a pure enough grade metallic zinc powder, you could always buy usp grade zinc oxide and convert it to metallic zinc powder yourself using electrolysis.

Hat tip to NurdRage for the procedure: https://www.youtube.com/watch?v=3X9c6epL7HQ

But strong aqueous ammonia will solubilize any trace of cadmium, yes. If one were to have a genuine concern about cadmium content, a further wash with fairly concentrated aqueous ammonia would probably be prudent as pure water would be capable of reprecipitating the hydroxide.

If you cannot find a pure enough grade metallic zinc powder, you could always buy usp grade zinc oxide and convert it to metallic zinc powder yourself using electrolysis.

And in that case, isn't the potential contamination of the sodium hydroxide an issue?

...Does this mean using ammonia for freebasing solves the potential cadmium contamination issue, as long as enough ammonia is used?