This is just a heating issue... There is no way you will get anything to distill over when you are only operating the bath 1.5° over the boiling
point of your compound, especially when your mixture has other higher boiling substances in it also. Think about it: could you ever distill water out
of an oil bath operating at 101.5°?And you especially couldn't distill water out of, say propylene glycol, at 101.5°. The boiling point of a mixture
is not often equal to the boiling point of the lowest boiling compound in a mixture.
I guess you are reading the wrong way into "distill at the lowest temperature at which the ethyl bromide distills over..." A big hint: if your ethyl
bromide isn't distilling over, it isn't hot enough.
I have done this only once, but it worked like a charm, I got just a bit below advertised yields, but that might have been because I was using acid
that was about 8% weaker than I had thought (only titrated it after the fact). I used KBr, at about half the scale you did (and I thought I was
foolhardy for trying a first time reaction on a mol scale...). I don't know exactly what I ran the bath at, but I know I had to raise it towards the
end and more ethyl bromide came over, and that I stopped it when the stillhead temp started rising sharply and reached about 50°.
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