Phosphoric acid catalysed isomerisation in IPA

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Hey guys, first post so be gentle :stuck_out_tongue:

Been reading for a few weeks now and I have to say, this site is invaluable. Great community, lots of useful information and helpful folks with big spoons. :+1:

I’m planning on running a phosphoric acid isomerisation after having mixed results with citric and have a few questions.

starting from >99% cbd isolate.

I’m wondering if refluxing in isopropyl should be avoided due to esterification? I have IPA, heptane, toluene and xylene on hand. I’ve read a few posts of guys using pTSA with ethanol and that’s quite terrifying, not wanting to make the same mistakes and speedrun dna mutation as my chemistry knowledge is limited, especially when it comes to interactions and side reactions. but I’m reading whatever I can find, trying to learn as much as possible to stay safe.

I’d like to avoid pTSA until I have a little more experience and feel like phosphoric acid would be a good stepping stone.

My plan was to reflux in IPA, water wash then dissolve oil in heptane followed by 3,3,3x base, salt, water washes.

No rotovap so I was planning on distilling off the heptane (@ atmospheric pressure) then purging in vac chamber before running through SPD

I have basic equipment (mostly cheap chinesium), glassware, condensers, spd head, 2stage rotary vane vac, aspirator pump, buchner funnel, filter media, 4a mol sieves + solvents listed above

I’m a medical patient in a country where it’s illegal without a prescription, our medical supply is imported old sub standard buds that are treated with radiation prior to packaging. this procedure dries out the buds making it very a unpleasant experience with extra high costs. I’m looking to replace this with my own supply and avoid the BM entirely.

Final product goals are a good d8-d9 mix that i’ll probably reintroduce <10% cbd and some terps to for vaping and occasional edibles

Thanks for reading and any advice would be appreciated :v:

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You’ll have to dissolve into heptane to water wash since IPA is miscible with water

Id start in heptane to make life easier personally

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yeah was thinking of heptane reflux but wanted to avoid the fumes as much as possible, IPA is a little less offensive. but yeah that’s probably the way to go.

so same parameters - reflux for around ~2 hours in heptane then continue as planned?

do you see any problems with me distilling off heptane without a rotovap apart from more work, i read it can be quite tricky to strip residue from the oil

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If you use any kind of alcohol, the reaction would produce some esterification, I would think.

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yeah, the mystery is what the reaction will produce in my circumstances, I know my reflux temperatures won’t be high enough but boiling the water off phosphoric leads to a mixture of ortho, pyro, and polyphosphoric acids and then in the presence of alcohol > pyrophosphate esters such as tetraethyl pyrophosphate (TEPP) which is highly toxic and not something I want to make at home lol.

I’ve seen people here using IPA with success so I guess I’m worrying a little too much, I’m going to sub the IPA for heptane after a little more reading. i’ll report back with how i get on over the weekend

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If your choosing your solvent based on the assumption that you will be exposing yourself to it, your doing it wrong! Make sure you have proper PPE for the reaction you are about to do. I’ve made cavalier decisions with chemistry in the past, gotten drunk on IPA fumes by accident before, and it wasn’t exactly “not fun” but it probably wasn’t good for my liver health. Since your small scale and I assume you don’t have access to a fume hood I would recommend a fredrichs or allihn condenser with the outlet port connected to a tube leading out the window.

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Yeah do the reaction in refluxing heptane. the phosphoric acid may not completely solubilize in the solvent, i’m not sure, but that should be ok if you are heating and stirring.

I have not had a lot of luck with base washing anything. it causes emulsions and deprotonates the phenolic O-H, leading to a pink-purple extract. My advice is separate the layers, then wash your heptane layer several times with brine. Conc NaCl is elite. Plus you can make it yourself with table salt.

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thanks, that’s a good idea. lab is a garden shed :blush: currently just have ducting above my table with a squirrel cage fan running outside into a carbon filter repurposed from an old grow room. i suppose if im worried about fumes i could run a tube straight into the ducting or extend the ducting down. yeah running an allihn for the reflux.

i have gloves, lab coat and safety squints. even with my ducting i can still smell the mixture while refluxing (citric) so it was pleasant but going forward it may become a problem. i could maybe improve upon this by building a makeshift fume hood but i feel okay with how things are so far. my fear was mainly nasty unknowns that could distill into my final product

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i was planning on epson/MgSO 4 for my salt washes, is table salt a better idea?

i’ll check the solubility tomorrow but it’ll be on a decent hotplate stirrer with a 80mm stirbar so should be okay

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My friend, most people converting CBD to THC are distilling nasty unknowns into their final products. This will continue until we can identify, quantify, and assess the risk of every byproduct this reaction makes.

Brine is pretty standard for washing. I don’t know anyone using MgSO4 but I don’t know everything!

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Never had this problem using baking soda

Only time i get weird colors is when i oxidize the reaction by adding water before it cools to room temp

Emulsions can be avoided by washing with water first to remove most the acid then following with your bicarb to fully neutralize

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Use canning salt that doesnt have a caking agent in it. Mgso4 can be left behind and cause side reactions if youre not careful. Never seen that happen with nacl but i also dont use salt on my final wash

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ah great, thanks guys. i’ll swap out the epson :+1:

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Ptsa in alcohol promotes much more byproducts, and lower yield in d8, about 70%, vs 92% in alcanes.

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I’m not 100% sure but I know a trick we use when making sulfuric acid from scratch is we run the gas excess/vent line through a sodium hydroxy or sodium bicarbonate solution then h20 solution then vent to air(way overkill, prob be fine with just hydrox solution) to neutralize any access sulfuric dioxide from the reaction. Not sure if that would help with toluene or heptane or w.e other solvent bi-product like S20?

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Any updates on your success? I actually just did a post about citric acid conversion and would love your input about it? Stay stoney and sorry for your shitty gov. laws. @Gwon

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Hey, sorry for not updating yet, i’m back at uni so not much free time to experiment/post and my cheap vacuum pump crapped out on me half way into distillation. currently awaiting delivery of a good used Pfeiffer Duo so my future distillations should go much smoother.

I ran two small 10g runs. one refluxed in IPA and the other in heptane. (the fumes were nothing to worry about I was just being over-cautious, but thanks for the tip that’s good to know)

I’d say that the IPA reflux seemed better due to solubility of the phosphoric acid but it was also wasteful on solvent as it was just washed away whereas heptane is recoverable.

I ran both for 2hrs, almost full conversion via beam test around 1hr30 (ipa) and ~1hr45 (hept) and both final products were very potent (small oral dose)

I’m looking forward to doing a larger run with proper distillation in the coming weeks

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the citric acid tek was enticing to me initially but the reflux times are very long and since trying phosphoric I probably won’t go back.

I tried it in water and neat. the higher temps-neat seemed to speed things up but as @JedClampet stated in his thread, it’s rather violent so make sure everything is well clamped and clipped.

with water I didn’t see much conversion until >12 hours anything I pulled before then would crystalise on cooling, neat I seen partial conversion via beam ~8hours @ 175-180. again this seemed like a lot of wasted time compared to the many other teks but it’s a good place to get your feet wet and familiarise yourself with the techniques while working with relatively safe substances

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Totally understand. My stir plate/hot plate just died on me after like 3 days of use. What I get for buying cheapo ones off amazon x.x; Uni is a lot to good luck there mate.

Nice. Glad to hear the good results. Potent in what ways can I ask? Notice any difference? can i ask why IPA vs. ethanol?

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Times aren’t so much a concern for me long as I can hit decent yields at targeted molecules and forego any nasty solvents/acids <3
Any links you’d recommend? Can I trouble you for some more details about your citric acid tek experience? What was potency like vs sulfuric?

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