A lot of people wish to reduce or dehydrogenate there cannabinoids.
they buy large amounts of catalyst and reuse it till it is spent.
what happens to it then …
are there other catalysts that will do the job just as well …
lets see what we can find
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Salt Lakes Metals Palladium Catalyst Preparation
https://saltlakemetals.com/pdcatalystpreparation/
Vogels Practical Organic Chemistry
pages 947 to 951
section on dehydrogenation and making palladium catalysts
if your doing the CBN SOP have a look at this pdf. they aromatize tetraline to naphthalene
in quantitative yield using the same reaction no solvent and all, but they use CO2 to remove
the hydrogen
if you have hydrogen in the reaction it will reduce simple.
vogel pd cats.pdf (1.0 MB)
Recovery of Palladium from Spent Activated Carbon-Supported Palladium Catalysts
Recovery of Palladium from Spent Activated Carbon-Supported Palladium Catalysts.pdf (387.5 KB)
Recovery of platinum from spent catalyst
Recovery of platinum from spent catalyst.pdf (198.7 KB)
Aromatization Studies. IV. Palladium Dehydrogenation of Arylcyclohexenones to Phenols
Aromatization Studies. IV. Palladium Dehydrogenation of Arylcyclohexenones to Phenols.pdf (333.5 KB)
Catalytic Hydrogenation over Platinum Metals
Catalytic-Hydrogenation-Over-Platinum-Metals.pdf (5.5 MB)
Organic Synthesis Collection Palladium Catalysts
Organic Synthesis Collection Palladium Catalysts.pdf (329.0 KB)
Preparing 5% Palladium on Carbon Catalyst
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Dehydrogenation with Sulfur, Selenium,and Platinum Metals
Dehydrogenation with Sulfur, Selenium,and Platinum Metals.pdf (7.1 MB)
Sulfur Dehydrogenation creates Hydrogen Sulfide.
It stinks to high heavens and it is very very toxic.
At low levels, hydrogen sulfide causes irritation of the eyes, nose, and throat. Moderate levels can cause headache, dizziness, nausea, and vomiting, as well as coughing and difficulty in breathing. Higher levels can cause shock, convulsions, coma, and death.
https://www.atsdr.cdc.gov/mmg/mmg.asp?id=385&tid=67
platinum is quite safe to work with if its properties are taken into account.
some platinum catalysts can be pyrophoric for instance adams catalyst.
Selenium will release Hydrogen selenide which is also a toxic gas again a very
very stinky and toxic compound
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Yeah h2s is no joke. Serious threat out in the oil life - heard lots of stories of whole crews dropping dead because it’s water soluble and it gets trapped in the snow, then spring time comes around and 
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Honestly every time I eat breakfast with a fried egg, the small amount of sulfur smell gives me horrific flashbacks. Almost ruined eggs for me. Ugh
H2S is the most corrosive “common” atmospheric pollutant.
The odor threshold is like about 0.5 ppb in the air.
At 150 ppm you loose the sense of smell, and awarness of danger.
From 300 ppm you can die… (in between you would first loose sight, then consciousness)…
I’ve been playing around with concentrated sulfide solution (10-300 mM) for more than a year now, researching how bentonite react with this compound. It is pretty easy as long as you work in anaerobic conditions (in gloveboxes), and above pH 8. Besides copper commonly reffered to on this forum, bentonites make very good sulfide scrubbers, and are employed as such in special air filter for H2S. There are various kind of bentonites, the Wyoming type, and the Fe rich ones are the most efficient. Basic KOH solutions makes also very good traps (the classical one in research litterature).
I can’t find the video, I’m pretty sure this in Madagascar, there is a group of people there who often goes up in the mountain, and stick their head into holes in the ground in order to get somehow high. It’s believed their getting high on H2S. 
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Holy crap! Intentionally getting high off that is crazy dangerous haha
Here is another paper on Pd/C dehydrogenation:
https://pubs.rsc.org/is/content/articlepdf/2015/sc/c5sc01044f
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It should be noted that danger is proportional to the amount generated.
1 mole of a standard gas at atmospheric pressure will fill 22 litres.
that means in an enclosed environment a reaction that evolves one mole of H2S will kill
everyone in the room if the area of the room is 73333 litres or 73.33 cubic meters.
to aromatize a cyclohexene ring we create 4 moles of H2S per mole of the cyclohexene.
thats nearly 300 meters cubed of death for every 314g of THC reacted to CBN.
requiring a minimum of 224g of potassium hydroxide in solution
or
requiring a minimum of 160g of sodium hydroxide in solution
to neutralize it.
It is always better to have more base than is needed and also to have a glass frit/sinter
and or stirring to make sure the gas is absorbed in the solution that it is bubbled through.
and of course a suck back trap to stop the caustic solution going back into the very very
hot reaction flask if there is a drop in gas pressure.
of course this is just acute toxicity and long term exposure is a risk as well.
Noish recommendations
Previously, the ACGIH recommendation for an eight-hour time weighted average (TWA) exposure limit was a concentration of 10 parts per million and the 15-minute short-term exposure limit (STEL) was 15 ppm . The new recommendations for airborne H2S exposure are a TWA of 1 ppm and an STEL of 5 ppm
It should also be noted that H2S is heavier than air so it doesn’t just float away as many may
think when it comes to gasses.
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Catalytic dehydrogenative aromatization of cyclohexanones and cyclohexenones
Catalytic dehydrogenative aromatization ofcyclohexanones and cyclohexenones.pdf (1.6 MB)
Molecular Iodine—An Expedient Reagent for Oxidative Aromatization Reactions of α,β-Unsaturated Cyclic Compounds (not nobel but as we have brought up sulfur and selenium this fits.)
Catalytic dehydroaromatization of n-alkanes by pincer-ligated iridium complexes
Catalytic dehydroaromatization ofn-alkanesby pincer-ligated iridium complexes.pdf (334.4 KB)
Cobalt–Pincer Complexes in Catalysis (not strong enough to aromatize THC but may reduce to HHC)
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Reaction-activated palladium catalyst for dehydrogenation of substituted cyclohexanones to phenols and H2 without oxidants and hydrogen acceptors
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