What is the boiling point of THC at 1 atm?

Wikipedia gives the boiling point of THC as 155-160°C @ 0.05mmHg. The problem is the low pressure which makes it irrelevant for most purposes. So, what is it boiling point at common pressure levels?
Remember that the GQ rules require the question to have been answered before starting with the jokes.

Also remember that the GQ rules prohibit advocating for illegal activity. So asking (and answering) about the physical properties of a substance are OK, but make sure you don’t use that as a springboard for how to get high.

315 F

Just google - tetrahydrocannabinol boiling point

About 429 °C, according to this interactive nomographic calculator. That is, assuming it doesn´t break down before that temperature, which I would rather suspect. (Of course, the vapor pressure could be fairly high well below boiling temperature!)

You can use a pressure temperature nomograph to approximate the boiling point of something at a different pressure. Some substances will decompose at high temperature, so you pretty much have to lower the pressure to get them into the gas phase.
Here’s one from Aldrich: https://www.sigmaaldrich.com/chemistry/solvents/learning-center/nomograph.html

That returns 426-433 °C.

That’s just the 50 mTorr bp from the OP, listed in Fahrenheit.

I would not recommend getting high from or otherwise ingesting any lab chemicals, be it simple table sugar…

Hmm. ChemSpider predicts 390.4±42.0 °C at 760 mmHg.

Yes, my bad - I realize my mistake. However, I have a suspicion that THC degrades at higher temperature therefore vacuum boiling/distillation is a must.

So the boiling point at 1 atm will be a theoretical day exercise.

Am I correct that the boiling point and the point at which a substance vaporizes are the same? Anecdotal data suggests that it evaporates far below 400 Celsius.

If I got that wrong, then I should reformulate my question to ask at what temperature it vaporizes at 1 atm.


Liquids vaporize at all pressures and temperatures. Boiling point is the temperature at which the vapor pressure of a liquid is equal to the external pressure ( 1 atm for atmospheric boiling).

It vaporizes at all temperatures at 1 atm.
It looks like you are doing something without understanding the basics. Since the board rules may prohibit you going into details, I suggest you look elsewhere. At least learn the basics first.

Moderator Note

It’s against GQ guidelines to tell people to “Just Google it.”

It’s especially against GQ guidelines to tell people to “Just Google it” when they’ve already posted the same answer in their OP. :wink:

General Questions Moderator

To use water as an example, to stay on the side of legality: Take a sealed room with zero humidity, and put an open container of water in it. The water will slowly evaporate. Eventually, one of two things will happen: Either the water will all evaporate, or (if there’s enough of it for the size of the room), the humidity in the room will reach 100%, and there will still be some liquid water in the container. Strictly speaking, after this point, the water will still continue to evaporate, but at the same time, water vapor will also be condensing at the same rate, so the net effect is no more evaporation. For any given temperature, there is some amount of water that will vaporize: This is called the partial pressure of the water at that temperature. As the temperature increases, the partial pressure of water vapor will also increase.

Now, at low temperatures, evaporation can only happen at the surface of the water. If it tried to happen in the interior of the water, making a bubble, the pressure (which is mostly a result of the air pressure) would push harder than the incipient bubble, and so the bubble wouldn’t be able to form. But at a high enough temperature, the vapor pressure of water will equal the ambient pressure, and at that point, bubbles can form, and so the evaporation can happen throughout the liquid instead of just at the surface, and so it’ll evaporate much more quickly. Evaporation in bubbles throughout the liquid is exactly what boiling is.

Not sure I understand this. Per my understanding (Nucleate, Film and Transitional) boiling - all of them occur at the heat transfer surface (like the bottom surface of a kettle) I.e. the vapor bubbles are formed at the heat transfer surface. It does not occur throughout the liquid.

Maybe bubbles form throughout the liquid when a superheated liquid is disturbed ? Or the pressure is lowered on a liquid below boiling point ?

Colibri : point taken and understood. Here’s some details if you care
If one googles THC boiling point, google gives results that points to other websites. However, if one spells out - tetrahydrocannabinol boiling point, google returns a result showing the actual answer. It is sort of asking googling 7+2 , when google does the math and shows you the answer on the top of the page.

I tried copying the http address of the search but on my iPhone safari, google searches did not show as a copy able link.

Now I misread the temperature (thought it was in C when it was actually F and matched the Wikipedia temperature). I did admit that in an post above :grinning:

All of Google’s results still come from other pages, though. It’s not like Alphabet, Inc. operates a drug chemistry lab that measured the boiling point of tetrahydrocannabinol themselves. It’s just that, for some queries, based on criteria that none of us mortals know, Google finds another website that it considers authoritative enough that it accepts that it “knows” it. But even then, there’s still some website that’s the source (usually, the one that’s the first hit listed underneath the big bold answer).

Lesson learned Chronos. Lately I am losing my faith on google and google news is a big reason.

My intent was not to post a snarky reply to the OP by asking him/her to google it, but to provide a search term that was providing a google vetted answer (learnt to be erroneous in retrospect).

Understand the term “vaporize” as it is commonly used in everyday speech rather than the technical definition.

At what temperature does THC vaporize at an ordinary pressure level?
Now, you could write a haughty pedantic post or a straightforward informative one. Decide which one you prefer to do.

But there is no way that it’s consistently used in everyday speech. What you’re basically asking, translated into technical speech, is “at what temperature is the vapor pressure significant?”, but that just means that you have to define what vapor pressure is “significant”.

Those are both the same answer.

When someone says: “The sun will rise at 5AM”, do you correct them that, actually, the sun doesn’t rise but it’s the earth that moves around the sun? When someone asks: “How many pounds does an M16 rifle weigh?”, do you ask them to specify on which planet because weight and mass aren’t the same? When someone asks what 365x24 equals, do you ask them to specify in which base system? No, because that would be annoyingly obtuse?
I will attempt to define “significant”: Vaporize 50% of 100mg of THC within 5 minutes in a 1 cubic centimetre space at 14.7psi.

Too specific to answer? Not enough? I await your non-answers.

I think what’s really being asked is, how do recreational vaporizers determine the proper temperature to use for a particular chemical? To avoid legal issues we can discuss what attribute of nicotine is used and extrapolate from there.