Sciencemadness Discussion Board

Separate pentane from ether?

DocX - 23-6-2017 at 12:43

Trying to get my ether from starting gas bottles, but all seems to pack pentane together with the diethyl ether. They have almost identical boiling points. So how would one go about separating them?

Mabus - 23-6-2017 at 13:44

I too have been thinking of a way to separate the two solvents from some starter fluids, as they're both very useful.
I noticed that methanol and pentane are listed as immiscible with another, and I was wondering if mixing the starter fluid with anhydrous methanol would allow to separate the pentane from diethyl ether and then fractionally distill the decanted methanol-diethyl ether solution to separate the two components. Unfortunately I can't find any information about the miscibility of methanol-pentane mixtures, nor if the two form an azeotrope (or all three).

AvBaeyer - 23-6-2017 at 16:04

Ether is soluble in conc H2SO4 whereas pentane is not so that provides a possible though dicey separation method. Dilution of the acid and heating the diluted mixture will drive off the ether. Unfortunately, I do not have at hand the solubility of ether in sulfuric acid so no comment on true practicality can be made.

AvB

UC235 - 23-6-2017 at 16:42

Don't bother? As extraction solvents, they're similar enough to work well. I've also run grignards in starting fluid ether that clearly contained some slightly higher boiling hydrocarbons and they went smoothly and in high yield.

If you need truly pure ether for something, make it from ethanol.