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Several hints how to make it easier and more efficient (note: only applicable when you go for neutral spirit).
1. Treat your raw spirit with small amount of NaOH. The goal is to decompose the ethyl acetate into ethanol and sodium acetate (also other esters). The amount should be realy small (as small is the content of ethyl acetate). It is better to put less than too much - you should make some experiments to establish the correct value.
2. After that you should add few drops of the KMnO4 solution (purple crystals). This is the strong oxidant transforming aldehydes into acids. It is so strong that it could oxidize even ethanol into acetic acid - this however is avoided due to high pH of the solution after addition of NaOH.
3. The reaction is rather fast so after couple of minutes you can see the precipitation of black and brown flakes of MnO2 - this is the end.
4. Filter the raw spirit and off you go with the batch distillation.
5. Please notice that the best result of the rectiffication you get only when the feed is the high strenght alcohol. Only then you get sharp division between different fractions. Water makes them more diffused.
From Andre.silent wrote:2. After that you should add few drops of the KMnO4 solution (purple crystals). This is the strong oxidant transforming aldehydes into acids. It is so strong that it could oxidize even ethanol into acetic acid - this however is avoided due to high pH of the solution after addition of NaOH.
theholymackerel wrote:On one hand ya make a good point, on the other hand the average poster here explodes into into a furious ball of explicitives at ANY HINT of cencorship, as my Private Message folder can attest to...
rad14701 wrote:seravitae, I am in total agreement that the moderators need to start buckling down on bad and dangerous advice being given... Some threads should be removed, not simply locked...
dixiedrifter wrote:Manganese is a neurotoxin and it is possible to get manganese poisoning.
dixiedrifter wrote:Personally I would never ever recommend putting Mn02 or or KMn04 in a still due to it being such a pain to clean up.
andre.silent wrote:a), b) The addition of NaOH should be very carefull. First of all the amount depends on the raw spririt quality - in particular on the content of acids and esters. Once you put to much you can end up with completely undrinkable product even after distillation.
Please find below the data from laboratory analisys of the raw alcohol before and after the chemical treatment.
Before chemical cleaning After chemical cleaning
Alcohol content % abv 88,9 89,2
Acids content mg/l 40,9 13,5
Esters content mg/l 509,6 59,2
However, redox potentials also presumably come into it, and that sort of information about whether ethanol oxidises easier or harder than acetaldehyde is not widely available.
In order to compare the purities of alcohols
I did some tests with KMnO4 by measuring the time it took for several alcohols to react and remove the purple color, and indeed tails & 1st pass distillates would bleach much faster than the final product.
pHneutral wrote:You know, considering the possible side effects of this sort of thing, and the potential expense, do you think it might be simpler to try auto-oxidation instead of chemical oxidation?
O2 is cheap.. you can even make it by cracking it out of water with electrolysis and use that for your auto-oxidation. Just vent the H2 pretty well
Seems a bit simpler than using all sorts of oxidizers, especially considering we're not going for commercial here (I'm assuming).
muckanic wrote:I suspect finding purish H2O2 would be easier than finding pure percarbonate. With any luck, liquid peroxide stabilisers wouldn't muck too much up.
muckanic wrote:None of this constitutes endorsement of the whole notion that chemical oxidation reduces congeners.