Sciencemadness Discussion Board

Advice needed on options for 90%+ EtOH

ChocolateStirBar - 31-10-2017 at 16:33

Hey guys.

Ethanol is a versatile solvent with a multitude of uses. It's also a psychoactive drug (that I do not imbibe in) and thus heavily taxed.

The current cheapest source I have for 95% non-denatured stuff is £18 for a single litre! Which is many many times more expensive than its methyl analogue cousin.

My options for obtaining 90-95% EtOH (in order to dry to an anhydrous state via 3A molecular sieves) are:

1) Distillation of cheap shitty vodka (unsure if would even save money vs buying 95%)

2) Sugar, water and yeast to get 20%~ ish then building a bokabob still in order to go for azeotropic EtOH in 1 run

3) Doing...something? With methylated spirits. Fractioning? No idea.

4) Hydrolysis of ethyl acetate via NaOH

Now, the latter is of extreme interest to me and TFSE gave a mixed bag on whether it actually worked or not. One problem which came to mind was the fact the NaOH should be introduced via aqueous solution, and considering I would be using an excess to ensure full hydrolysis, this may be far from ideal.

Does anyone have any suggestions (and ideally experience with #4) on the best option to obtain pure ethanol at home, or for a similar price to other solvents? It does not need to be fit for consumption.

On that note, does denatonium affect reactions at the levels it's added at (for the lucky people who get to buy azeotropic EtOH with only that as an additive)?

Corrosive Joeseph - 31-10-2017 at 16:50

Myself and a friend looked into this for far too long and came to a few conclusions -

1 - First, it depends on how much you need

2 - Vodka is just too expensive to start from. Period

3 - Turbo yeast and sugar with dedicated copper/stainless steel still is the way to go if you want solvent on tap

4 - Regarding Denatured : I don't know where you are but here in Europe the usual brew is......

"The European Union agreed in February 2013 to the mutual procedures for the complete denaturing of alcohol:[9]
Per hectolitre (100 L) of absolute ethanol: 3 litres of isopropyl alcohol, 3 litres of methyl ethyl ketone and 1 gram denatonium benzoate."
https://en.wikipedia.org/wiki/Denatured_alcohol

Apparently a reflux in excess NaOH and activated carbon followed by a slow distillation works here.
I haven't done this yet but plan to pursue it if I need a small amount.

Disclaimer - I would imagine it would be very difficult to fully remove traces of IPA which is okay if one just wants an general alcohol solvent

/CJ


[EDIT1] - Stupid Typo
[EDIT2] - Disclaimer

[Edited on 1-11-2017 by Corrosive Joeseph]

[Edited on 1-11-2017 by Corrosive Joeseph]