Sciencemadness Discussion Board

How to identify methanol, ethanol, isopropanol at home?

TmNhRhMgBrSe - 3-7-2020 at 23:05

Some black heart pharmacies sell methanol to lie consumers. How to identify methanol, ethanol, isopropanol at home?
https://www.passiontimes.hk/article/02-21-2020/60243

[Edited on 20年07月04日 by CELamCheng]

Sulaiman - 4-7-2020 at 00:21

By smell,
BUT if not familiar or unable to distinguish then b.p. is usable.
unless the ethanol is dilute (<40%) when it could have similar BP to isopropanol.

P. S. Also flame test : methanol burns with a very faint blue flame, ethanol blue with a little yellow, isopropanol more yellow.

EDIT : see next post. None of the above would work. Sorry.

[Edited on 4-7-2020 by Sulaiman]

mackolol - 4-7-2020 at 10:08

Quote: Originally posted by Sulaiman  
By smell,
BUT if not familiar or unable to distinguish then b.p. is usable.
unless the ethanol is dilute (<40%) when it could have similar BP to isopropanol.

P. S. Also flame test : methanol burns with a very faint blue flame, ethanol blue with a little yellow, isopropanol more yellow.


[Edited on 4-7-2020 by Sulaiman]


I strongly doubt that the methanol would be pure. And if not, it isn't possible to recognise it by smell neither by flame colour...

outer_limits - 4-7-2020 at 14:26

You could use Lucas' reagent to differentiate between secondary and primary alcohols.

To differentiate ethanol from methanol you could perform simple iodoform test

This combination is sufficient in qualitative context if you know that your solution consist of one or combination of 3 mentioned: MeOH, EtOH, IPrOH

Boiling point could be checked only if you are sure that you have one of them in its pure form, but I would rather rely on chemical tests.



[Edited on 4-7-2020 by outer_limits]