Everyone who needs good separation should use efficient and insulated column, steady heating source, adjustable reflux ratio distillation head.
I did an experiment with fermented apple cider and tried how much pure ethanol I can get. I synthesized a lot of ethyl esters with amazing scents and
I hate commercial ethanol denatured with stinky butanone.
I did 2 simple distillations of fermented apple cider and got cca 80% ethanol where could be cca upto 1% methanol (from pectin, apples are reach
source of pectin), ethyl acetate and higher chain alcohols. Then I performed last step which was distillation on column. Imagine that 2 liters in the
distillation flask should evaporate and condense few times until all the lower boiling sideproducts pass from distilling flask into the colum and then
to the top of the colum (methanol and then azeotrope ethyl acetate + ethanol + water). Thus you need very high reflux ratio, like 10 drops returning
back into the distillation flask and 1 drop taken into the receiver and starting collecting distillate must be AFTER enough of time so the lower b.p.
sideproducts have enough time to pass from distillation flask into the colum (the whole content in the distillation flask should evaporate and
condense very likely more than 1 time because b.p. differences are only at scale of 10-20 C). If you start to receive the main fraction too early
there are still lower b.p. sideproducts in the distillation flask! It just requires some time and patience and efficient apparatus.
I tested 1 m long Hempel column packed with Raschig rings, variable reflux ratio distillation head with reflux ratio 10:1. Final ethanol was very
pure, methanol below 0,1%, ethyl acetate below 0,1% - my friend Bedlasky performed GC in his job in a factory where they produce a lot of products,
one of them diethyloxalate so he controls ethanol they import into the factory and he wrote me that they never had such pure ethanol as I produced in
home lab apparatus.
Here the experiment, there are plenty of photos with thermometer during time what happens and how long does every step last:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
Put it simply, the main fraction was started to collect after 1 hour, heating mantle at the power just below flooding column. Every picture contains
exact time in its name. It could be possible to approximate how much condensate returned back into the distillation flask during that 1 hour.
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
