Sciencemadness Discussion Board

Free Radical Alcohol?

Meltonium - 20-11-2016 at 14:18

I attempted an experiment to create hexanol from n-hexane and hydrogen peroxide. I became curious after I saw a video on how water was purified using H2O2 that was split into free radicals.

I added 50ml of n-hexane to a flask followed by ~140ml of semi-concentrated H2O2. With rapid stirring, the mixture was kept under uv light of ~395nm for 1.5 hours.
The mixture was then setup for fractional distillation.
Unusually, a liquid, presumed to be the n-hexane, distilled over at 58C. This is peculiar because n-hexane's BP is supposed to be 69C and the air pressure at the time was not enough to explain an 11C difference.
After all of the low-boiling liquid had been collected, the heat and stirring was removed. The now hexane-free liquid was tested for H2O2 by adding a minute amount of MnO2 to a small sample. The reaction bubbled quite vigorously.

I had planned to use the BP of the hexanols' to see if any had been created, but since nearly the full 50mL of hexane was distilled over, I don't think that process would yield anything.

Is there any other way to test for the alcohols in the mixture?

aga - 20-11-2016 at 14:36

Well, with such scant information, it's unlikely that even a seasoned chemist could help.

Maybe knowing the concentration of H2O2 might help.

Personally i have not the slightest clue.

Meltonium - 20-11-2016 at 14:40

The last time I titrated the peroxide it came out to be about 17% give or take. However, that was a few weeks ago.

Metacelsus - 20-11-2016 at 14:53

The hexane-water azeotrope boils at 61.6 °C. The remaining 3.6 °C of deviation could be explained by an erroneous thermometer, or pressure differences. You could check your thermometer by distilling water.

If you want to spice things up a bit, you could add some iron salts to the peroxide, and get Fenton's reagent.

[Edited on 11-20-2016 by Metacelsus]