• Members of the previous forum can retrieve their temporary password here, (login and check your PM).

Zinc for THH conversion

F

freedissociation

Rising Star
Hello Fellow Journeyers,

Grateful for this resource and the opportunity to make this my first post.

Background: I have a BS in molecular biology with a minor in chemistry.

A couple questions regarding zinc for THH conversion:

1) All posts and guides seem to describe zinc "dust" or "powder", and subsequent chemical separation steps to remove the metal. Is it not an option to use larger zinc granules on a magnetic stir plate? Certainly the reduction reaction to THH would proceed much slower with zinc granules, but the zinc separation would presumably be simpler and more definitively remove heavy metal impurities?

2) Any recommendations on a trustworthy source of reasonably priced and high quality zinc dust or granules? The lab grade versions appear to be ~$1/g; is that reasonable?
 
From what I understand the zinc will disassociate into zinc ions and will form zinc acetate or whatever acid you have.

You can salt out with sodium chloride saturation keeping the zinc in solution.
 
Use ammonia as your base will help ensure you're only left with harmala alks.

keep in mind when you separate the harmala, it can be quite hard to separate the harmaline and harmine even at the right ph levels. Last lab results I had done iirc from endlessness indicated close to 50/50 mix thh to harmine. I believe he said that this was fairly standard with other samples he tested. Hopefully he chimes in and confirms. If your starting material is bought harmaline this might be a different story.
 
modern said:
From what I understand the zinc will disassociate into zinc ions and will form zinc acetate or whatever acid you have.

You can salt out with sodium chloride saturation keeping the zinc in solution.
Click to expand...
Ah yes you are correct, the zinc does dissociate into ions.
Funny, I was vaguely remembering metal catalysts (nickel, palladium, platinum) in hydrogenation reactions as surfaces that do not erode.
A simple search reveals: "Catalysts are usually classified into two broad classes: homogenous and heterogenous. Homogeneous catalysts dissolve in the solvent that contains the unsaturated substrate. Heterogeneous catalysts are solids that are suspended in the same solvent with the substrate or are treated with gaseous substrate."
 
freedissociation said:
Ah yes you are correct, the zinc does dissociate into ions.
Funny, I was vaguely remembering metal catalysts (nickel, palladium, platinum) in hydrogenation reactions as surfaces that do not erode.
A simple search reveals: "Catalysts are usually classified into two broad classes: homogenous and heterogenous. Homogeneous catalysts dissolve in the solvent that contains the unsaturated substrate. Heterogeneous catalysts are solids that are suspended in the same solvent with the substrate or are treated with gaseous substrate."
Click to expand...
Hello and welcome to the Nexus. Nice to hear of your science background 😊

In this case, zinc is a reagent rather than a catalyst. It gets used up during the reaction, dissolving into the aqueous solution as it gives up electrons into the solution. Only some of these electrons are taken up by the harmaline molecules, hence the large amount of hydrogen given off as effervescence. Catalytic hydrogenation might prove more efficient, but this and its cost-effectiveness would depend on the catalyst and the reducing agent used.

I wonder if formic acid and Pd/C would do the job? @Mindlusion would know the answer to this question.

A homogeneous catalyst would be out of reach for most home enthusiasts, I suspect.
 
Transform said:
Hello and welcome to the Nexus. Nice to hear of your science background 😊

In this case, zinc is a reagent rather than a catalyst. It gets used up during the reaction, dissolving into the aqueous solution as it gives up electrons into the solution. Only some of these electrons are taken up by the harmaline molecules, hence the large amount of hydrogen given off as effervescence. Catalytic hydrogenation might prove more efficient, but this and its cost-effectiveness would depend on the catalyst and the reducing agent used.

I wonder if formic acid and Pd/C would do the job? @Mindlusion would know the answer to this question.

A homogeneous catalyst would be out of reach for most home enthusiasts, I suspect.
Click to expand...
Thank you for your further clarification.

It appears that Sasha used platinum as a catalyst, with NaBH4:

Erowid Online Books : "TIHKAL" - #54 TETRAHYDROHARMINE

Entry #54 TETRAHYDROHARMINE from TiHKAL by Alexander & Ann Shulgin.
www.erowid.org
 
freedissociation said:
Thank you for your further clarification.

It appears that Sasha used platinum as a catalyst, with NaBH4:

Erowid Online Books : "TIHKAL" - #54 TETRAHYDROHARMINE

Entry #54 TETRAHYDROHARMINE from TiHKAL by Alexander & Ann Shulgin.
www.erowid.org
Click to expand...
Indeed, there will be several roads up the same mountain. One day, I'd like to try using Hantzsch dihydropyridines for a few interesting reductions, although I probably shouldn't get too far into that here.
 
Back
Top Bottom