[purplemonkey123]

Hello! In my experiment involving the synthesis of tylenol, the melting point obtained was 150 degrees Celsius. However the "real" or "expected" melting point is 131 degrees Celsius. What does this difference in melting points say about the chemical purity?

My guess would simply be that the chemical is not 100% pure.

[Borek]

Contamination always lowers the melting point.

[mikasaur]

Contamination always lowers the melting point.

Chem uber-newb here. But is this actually true? Or only true for tylenol?

[kriggy]

Its always true.
https://en.wikipedia.org/wiki/Eutectic_system

However, you might get different melting point because you crystalized your compound from different solvent than the one used by autors who claim 131. I suggest running HPLC-MS or NMR.

Also, by making tylenol you mean the active ingredient Paracetamol or what compound exaclty? (my google search shows only paracetamol). Anyway, if its the former, than paracetamol has mp of 169°C...

[mikasaur]

Eutectic system... very interesting!

Though the OP stated that their measured MP was higher than expected. But it's lower than the MP for pure paracetamol/acetaminophen.



It seems like it's not pure acetaminophen, but I wonder where the 131° came from.