Hey everyone

I was recently watching a video on youtube where they used evaporation to purify Iodine crystals. They did this by heating the crystals in a beaker with a round bottom flask filled with ice water covering the top. The crystals would liquefy and then evaporate before recrystallizing on the round bottom flask.

I was wondering if this same procedure was possible but to instead put a DMT Gramine admixture in the beaker, heat it to 90°C (while covering the top with an ice water filled round bottom flask) and have the DMT recrystallize on it while leaving the Gramine on the bottom.

If anyone could verify or further support this that would be great. Thanks in advance.

You probably want to use 90 °C for the separation because of the Wikipedia entry. But as stated in the link above this value is totally wrong.

Correct ranges would be

melting point (based on cristalinity): 50 - 85 °C

boiling point: 155 - 165 °C

So you would need a much higher temp to make DMT vaporize. Now Gramine in Wikipedia is told to melt at 138 °C. But this seems again quite strange as it does not incorporate any structures that should shift its properties any way off from DMT so it should be in both cases a little below DMT. In this case it would make much more sense that the boiling point of Gramine is 138 °C.
If that would be true then you could separate both by turning the heat to 145 °C and collecting the Gramine on the top glas piece. But the purity of the sublimation product on the top will be higher than the purity of the residue on the bottom, so this way you may still have Gramine in your DMT at the bottom, just very pure Gramine on the top cooled glass.

Please forgive me as I am not a chemist and I got a C- in high school college prep chem. Doesn't the vapor pressure of a compound determine how prone it is to vaporize. I think in the experiment you viewed (I have watched that same Youtube video btw) the iodine sublimates not melts then vaporizes then condense. So the Iodine crystals go directly to gas then condense as crystals on the bottom of the cold glass beaker. Not sure what bearing this has but thought I would throw out what little knowledge I had. Maybe point you in the direction of an answer?