December 27, 2024, 02:53:49 AM
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Topic: Does the atmospheric pressure affect decomposition temperature?  (Read 952 times)

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Offline Jfalken

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Does the atmospheric pressure affect decomposition temperature?
« on: September 04, 2020, 05:50:15 AM »
So lets say that compound A decomposes at 110 degrees Celsius and I have it in the rotovap.
Now, as I am reducing the pressure so the solvent will boil away quicker - will this somehow affect the compound as well?
Could compound A then instead decompose at 80 degrees Celsius?

Logically I would say no, but sometimes I see color changes when the vacuum is getting higher.

Also, what do you guys think is the best way of getting the product out of the rotovap flask?
The solvent has evaporated and the compound is very sticky to the surface of the flask.
Adding the same solvent is of course not an option because then I have to redo the process again.

Offline hollytara

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Re: Does the atmospheric pressure affect decomposition temperature?
« Reply #1 on: September 05, 2020, 11:13:15 PM »
So it isn't common for lower pressure to increase decomposition, but it can happen - if one of the products is volatile. 

There are adapters where you can rotovap a vial so when you are done your compound is in a vial!  There is a threaded cap that fits the vial with an opening for the vapors to escape. 

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