I have denatured ethyl alcohol which was obtained this formula;

In 100 L ethyl alcohol there is 0.8 gr denatonium benzoate and 78 gr tert-Butyl alcohol.

Is there any way to obtain absolute ethyl alcohol from that mixture.

  • 1
    $\begingroup$ What applications are you conceiving needed absolute ethanol for? Most things I can think of (besides drinking and spectroscopy) should tolerate those two impurities. $\endgroup$
    – Ben Norris
    Mar 15, 2016 at 21:13
  • 1
    $\begingroup$ I'd never try to "undenature" ethyl alcohol to drink it. // Denaturants are chosen specifically to be hard to remove. The denatonium benzoate could probably be removed effectively by distillation which wouldn't remove the tert-Butyl alcohol which is poisonous for animals (including humans). $\endgroup$
    – MaxW
    Mar 15, 2016 at 21:32
  • $\begingroup$ I suggest purchasing Everclear (95% $\ce{EtOH}$) and using calcium chloride to dry it. $\endgroup$
    – A.K.
    Mar 16, 2016 at 16:22
  • $\begingroup$ To remove tert-butanol you could add hydrochloric acid to selectively produce tert-butyl chloride, which would be easier to separate. $\endgroup$
    – A.K.
    Mar 16, 2016 at 16:24
  • $\begingroup$ @A.K. after adding hydrochloric acid is it possible to remove mixture from tert-butyl chloride with distillation and also denatonium benzoate? and also how is it work other method with everclear? $\endgroup$ Mar 16, 2016 at 17:45

2 Answers 2


Please note that the following is not meant to be used as an instruction!

According to an article on Detection of Denatonium Benzoate (Bitrex) Remnants in Noncommercial Alcoholic Beverages by Raman Spectroscopy, published in J. Forensic Sci. 2014, 59, 1358-1363 (DOI), the manufacturers of illegal alcoholic beverages often use sodium hypochlorite ($\ce{NaOCl}$, household bleach) to remove the bitter taste of tax-free technical ethanol.

In the study above, the authors used legally available legal alcoholic beverages (vodka, cognac, etc.), and denatured/de-denatured them under controlled conditions:

The separate batch of purchased alcoholic beverages was denatured with 20 mg/L of denatonium benzoate, after which 1.33 mL/L sodium hypochlorite was added.

Spectroscopical measurement of the samples thus obtained clearly showed degradation products of the bitterant.

While hypochlorite treatment might be suitable to remove the bitter taste, this doesn't imply that the result is healthy or recommended to consume.

  • $\begingroup$ The hypochlorite treatment wouldn't remove the tert-Butyl alcohol which is poisonous. $\endgroup$
    – MaxW
    Mar 16, 2016 at 6:05
  • $\begingroup$ @MaxW "Poisonous" is a bit exaggerated, isn't it? LD50 (oral) is about 2.7g/kg in rats. It is H332 (harmful if inhaled), not H330 ot H331. $\endgroup$ Mar 16, 2016 at 6:21
  • $\begingroup$ actually I dont have problem with bitter taste. Other ingredients apart from ethanol brokes my sensitive calculation and almost impossible to find pure ethanol because of idiot regulation for tax here. There is only way to make own ethanol via fermantation. But takes a lot of time and so tiring for me. That is why I am asking is there a way remove other chemicals from the denatured alcohol. $\endgroup$ Mar 16, 2016 at 16:53

Does not address the specific question, but rather a comment on the original:

Use Benzene-Water-Ethanol ternary azeotrope (bp 64.9, 74.1% Benzene, 7.4% Water) to dehydrate Everclear. You'll need to add 10 times as much benzene as water, (therefore roughly half the total amount of liquid you are dehydrating). Adding excess benzene leads to the Benzene Ethanol azeotrope (bp 67.8, 67.6% benzene), so err on the side of slightly more than half the volume of alcohol.

Both of these azeotropes are well less than the bp 78,2 for ethanol, so with some good technical skill you will be able to distill this. You will lose roughly 15% of the alcohol in the azeotropes.

This is more laborious than using CaCl2.


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