FriendlyFinger - 17-12-2007 at 20:40
EtOH distillation.
If you have a 50% water/Etoh mix and distill, will it come over at the same temp as say a 10% water 90% Etoh mix, if you don't use a column?
contrived - 18-12-2007 at 16:45
Please read up on simple distillation; there's readily available information in books and online. We don't like to answer questions born of sheer
laziness.
evil_lurker - 18-12-2007 at 23:35
EtOH disillation ain't exactly simple.
And while one can read all they want, here is some practical observations of the process...
When you initially distill alcohol, that which has just been fermented, you will initially take off approximately one third of the volume. This will
"strip" the bulk of the alcohol if you will, leaving you with some EtOH in a concentration of around 40% depending on the concentration of the initial
wash.
Now then, if you redistill the alcohol without a column, the very first part to come off will be in the 90%+ range, and as it is gradually distilled
off the EtOH content in the vapor will fall.
So in other words, if your doing a second distillation without a column, the final concentration will be an average of the amount of EtOH in the
vapor... the larger the fraction, the lower the final concentration of EtOH.
A reflux column will allow for a smaller final fraction at a much higher proof... a 300mm packed with copper or stainless scrubbbies is the bare
minimum I would recommend for such a distillation, 500mm or larger preferable. The colums have to be run SLOWLY 1-2 drops per second, otherwise their
height equivalent to theoretical plate ratio will go into the toilet.
Also it should be noted that its not practical on a lab scale to get 100% of the EtOH.. in fact, a loss of 20% or so is acceptable considering the
time needed to be invested in recovering the last amounts.
Once you do 5-10 runs you'll get the hang of it.
chemrox - 19-12-2007 at 14:56
yes but he can find all this online including distillation curves and there's a book: http://www.home-distillation.com/ where a lot of this is discussed. You're a generous fellow, Evil and we all appreciate it.