Boiling Point of THC


Using this nomograph (borrowed from @canndchas on IG)

We can see how the boiling point of THC (or anything) is reduced as vacuum increases

Beaker (@redturtle984) • Instagram photos and videos

great juxtaposition of relevant facts


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thanks for this great info!


Great chart. this is helpful.


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Terpene boiling points

Curve fitting is so powerful. Would love to see the spreadsheet myself :wink:


Check out sigma Aldrich’s tool


So why is the nomograph reading the normal boiling point as over 400C, when I always hear it reported as 157C?


also… 1896? Is that date correct?


That lines up perfectly with what we saw during dial in of the BR Inst 9200. At .25-.08mmHg our THC fraction arrived between 172-165C.


Well don’t all the lines on the nomograph have to go through the normal boiling point of the compound? If they’re all going through at the 425C, that would imply that the normal boiling point of THC is 425C. I thought the normal boiling was around 160C. Am I missing something?
Here’s a link to Russo’s paper and he says all the boiling point values are at 760 mm Hg unless stated otherwise. There’s a big table with a bunch of cannabinoids.

Then again, wikipedia says 155 C at .05 mmHg.

This probably explains what’s going on in the BR though. Wow. It’s a good thing my office is on the first floor.


Damn! it is from 1896. cool.


The extended Antoine equation is the formal way of formulating vapor pressure data for pure components. Parameters are fitted to the equation with the relevant data very easily.


I remember discussing this with Photon_noir when it was fist released and wondering if it had been adjusted for enthalpy of evaporation. Has anyone verified this with real world data?


I believe the 157°C people see is for molecular distillation, so 0.01 Torr


To call it anything less than a gong show would be dishonest.


Would be really helpful, and should be published in the journal of fluid phase equilibria. The Claudius Clapyron equation is theoretical, but arguably is valid at such low pressures where ideal gas law is approached. Chemical engineers use extended Antoine equation, based on actual physical property data (e.g. Dortmund databank), obtained in multiple experiments in controlled settings. That being said, this property of boiling point is only valid for a pure component, i.e. it’s pure component vapor pressure… When dealing with a mixture of cannabinoids and other shit, boiling point is supplanted by bubble point/dew point, and one needs to establish the vapor liquid equilibrium to answer the real question being asked, which I think is, ‘what temperature is my liquid phase when the condensing vapor phase is most enriched in THC, given a constant absolute pressure?’ .


Well said. Your boiling point in every distillation will be different unless your mixture is exactly the same. Therefore in things like an SOP, you would have a range of temps and another indicator of what the fraction is. A singular “boiling point” is pretty fucking useless honestly.

I think a binary approximation wouldn’t be too bad in this case (CBD+THC). Binary phase diagrams are still simple experimentally and easy to understand. Let’s say your crude is 50% cannabinoids. Then more than 95% of those cannabinoids are probably THC or CBD. The mol fractions in each phase of other cannabinoids/compounds is probably small enough to ignore at that point.


Agreed. What is needed for the industry is someone to determine the binary interaction parameters for the two prominent cannabinoids. Then activity coefficient models can do good job of predicting phase behavior in software like AspenPlus or the free ChemSep. I would bet a coffee someone somewhere actually has attempted the tests and published the data on the above, in a journal somewhere. Can anyone find it?