Ask A Scientist Chemistry Archive

name         Len W.
status       educator
age          50s

Question -   I am trying to educate home distillers about distillation
problems,  everything not being what it seems,  I am at the moment trying
to stop home distillers from redistilling and filtering denatured ethanol
with home made or commercially manufactured reflux distillation and
carbon filtering equipment.

I am hopeful you can me a good reason that I can relate to people that
will dissuade them from what I feel may be a very dangerous practice.
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There are several dozen types of denatured alcohol, depending upon the
intended end use (e.g. fuel, coatings and finishes, rubbing,..., the list is
long). The federal government controls the formulation of the various types.
They are formulated because ethanol intended for human consumption is highly
taxed, while the denatured versions are not. They have been carefully
formulated to make it very difficult, if not impossible to: 1. Know what the
denaturants are. and 2. To separate them by any reasonable physical and/or
chemical processes. The denaturants are either very toxic (e.g. methanol),
or distasteful (e.g. butanol) -- or both.
Attempting to remove them, even using sophisticated separation techniques is
both dangerous (because you do not know what you are trying to separate) and
futile. Otherwise there would be a whole black market industry devoted to
doing this. Remember prohibition. While I do not suggest the alternative,
because it too is illegal and/or regulated, it is well known that producing
your potable ethanol from grain, grapes, or hops is cheaper and safer.

Vince Calder
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Len,

You might remind them that the practice is illegal. AND, unless all traces
of the denaturant are removed, drinking such a "home brew" could prove
fatal. If their intent is to acquire 95 % ethanol with which they may
fortify other alcoholic drinks, why don't  these "home distillers" simply
purchase grain alcohol ("Everclear", "White Lightning". etc.) through legal
channels at a liquor store?

Regards,
ProfHoff 505
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There are several questions anyone contemplating detoxifying denatured
ethanol by distillation needs to be able to answer:

- What denaturants are present?
- What concentrations of the denaturants would be problematic?
- How can you measure the concentrates of the denaturants in the
condensate/filtrate?
- What are the accuracies and limits of detection of your measurements?

Just because two compounds have different boiling points and can be
separated by distillation does not necessarily mean that any distillation
apparatus and procedure will separate them completely.  Not all distillation
procedures are equally efficient, and some separations are more demanding
than others.  There is also the possibility of azeotropes, in which a
specific mixture of two or more components distill together.

Richard E. Barrans Jr., Ph.D.
Director of Academic Programs
PG Research Foundation, Darien, Illinois
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