blackspirit
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Using leftover ethanol from brewing as solvent?
I use to make my own alcohol with bokakob column still and it produces a decent 95abv alcohol for recreational uses. Alongside this what is called
hearts, stuff called foreshots, heads and tails are collected and generally form up to 40% of the total distillate, which is set aside or discarded. I
was wondering could this be sufficiently pure for chemical synthesis use as a substitute for otc ethanol? The ethanol sold here is highly denatured
and usually mixed with other nasties, like detergents and potable alcohol is exceedingly costly due to taxes. The major portion should be ethanol with
minor impurities that are prevalent enough to render it either unpalatable or health hazard.
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Texium
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The heads will likely be a mixture of methanol, ethanol, and small amounts of light esters. The composition will vary depending on what you fermented.
It's great for cleaning, but no good for synthesis. The tails you should be able to redistill using a better column to get more near-azeotropic
ethanol. You can treat this with NaOH to break down any esters and neutralize acids and distill again from the NaOH. After that distillation you
should have quite pure near-azeotropic ethanol.
The "hearts" would of course be the best fraction as far as ethanol purity goes, but I understand if you want to retain that for recreational
purposes.
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happyfooddance
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Methanol is a near non-existent impurity in home-brewed washes, contrary to popular belief. I doubt any home brewed ethanol has any appreciable
methanol unless it was brewed from fruit. It is mainly pectin and methyl esters that contribute to methanol. Commercial apple and orange juices have
many times more methanol than even poorly brewed washes.
Also, your heads will be much easier to get to a high purity than your tails. The main impurities are always higher in your tails, they come in the
form of higher alcohols, esters, and aldehydes that come over with the water. This can also be purified quite easily.
Texium's suggestion about distilling from base is a good idea, distilling from salt is a better one. Distilling from NaOH or even sodium carbonate
(especially a tails cut) will free ammonia which will come over in the distillate. Add some citric acid and re-distill to remove ammonia if you go
this route.
This alcohol is great for making ether and many other things, I would never throw it out.
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unionised
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There's often a fair bit of acetaldehyde in the lightest fraction.
Reduction to alcohol is probably unworthwhile.
It might be possible to separate it in a clean enough state to use as a reactant. (I'm thinking maybe as a bisulphite adduct or something.
In any event, you don't want it in the "recreational" stuff.
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Sulaiman
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As brewing and distilling are clearly not a challenge,
the relative cost of 'hearts' as a laboratory reagent is very low,
so other fractions may be more useful for cleaning or burning ?
CAUTION : Hobby Chemist, not Professional or even Amateur
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happyfooddance
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Quote: Originally posted by unionised  | There's often a fair bit of acetaldehyde in the lightest fraction.
Reduction to alcohol is probably unworthwhile.
It might be possible to separate it in a clean enough state to use as a reactant. (I'm thinking maybe as a bisulphite adduct or something.
In any event, you don't want it in the "recreational" stuff. |
This is very true. My uncle does analytics for DUI cases. He was explaining to me how he calibrates their chromatography equipment, and he quipped
that not only can he tell how intoxicated a person was, but also how hungover they were the next day, based on acetaldehyde levels.
Acetone is also a very common "heads" contaminant. It mainly comes from the action of yeast on starches which were not first converted to sugar during
the mashing process. This is why homebrewing supply places carry iodine, for starch testing. Acetone also is produce by stressed yeast.
I disagree that homebrewing and distilling is not a challenge. I hope no one here has the notion that this "hearts" cut from a stripping run is
reagent grade... Maybe after carbon filtration and multiple distillations, and at least one through copper column packing. Many people have spent many
years learning how to efficiently brew and distill quality alcohol with certain characteristics.
It isn't the most difficult synthesis and commercial yeasts today are good and strong, sugar is cheap! but if you don't know what you're doing you
will certainly end up with stagnated washes and tons of congener. And they don't distill out like one would hope.
If it was not difficult, all vodka would taste like grey goose.
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Sulaiman
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| Quote: Originally posted by happyfooddance | I hope no one here has the notion that this "hearts" cut from a stripping run is reagent grade...
If it was not difficult, all vodka would taste like grey goose. |
Based on the opening line of the OP ;
" I use to make my own alcohol with bokakob column still and it produces a decent 95abv alcohol for recreational uses. "
I assumed that the 'hearts' would be fairly pure azeotropic ethanol,
For my own distilled ethanol I get a friend to taste for purity for me in lieu of proper chemical tests,
so I've only ever known the ethanol ABV, I've never really known the purity.
Also, I've never done an experiment yet where I needed truly pure ethanol, so I was guessing ... sorry 
CAUTION : Hobby Chemist, not Professional or even Amateur
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ave369
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I, as an experienced moonshiner, can attest that the "heads" (called "pervach" in my country) make good fuel for spirit lamps if made on a doubler
still, but are near useless as a source of chemicals of reasonable purity.
Smells like ammonia....
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aga
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What is "leftover" ethanol ?
Surely there is no such thing.
Edit:
... apart from eggnog.
[Edited on 7-2-2018 by aga]
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Inerdgas
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Happyfooddance (and others)
What would be a good way to increase yields of methanol? Where I live it is possible to get hold of methanol, but it is a nuisance. You can
buy methanol based fuel for RC-engines, which has a certain amount of engine oil added. The oil would be easily separated by distillation, but any
purchase is logged and reported to the police. And with certain stupid public statements from the police recently I'd rather avoid that.
So I have tried looking into alternatives. My first bet was going for destructive distillation of wood, but it seems like the percentage of methanol
from wood vinegar is quite low, so I would have to work at a large scale to get any real amount of product.
Finding data on fermentative methods have also been a bit beyond me. It seems like the pectin content determines the methanol output, but wether the
yeast can work on pure pectin or needs other simple sugars is a bit unclear to me..
Does anyone have any idea of possible yields of methanol from a basic fermentation if I either add a bunch of store-bought pectin, or ferment from
something like unripe redcurrants?
I'm just planning to use it for some fischer esterifications, so I don't really need huge amounts
(Sorry about formatting or other errors, first post)
[Edited on 13-2-2018 by Inerdgas] typos
[Edited on 13-2-2018 by Inerdgas]
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happyfooddance
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Most automotive stores carry a product called "Heet". It is a gas line anti-freeze/water removal agent. It is very pure and dry. I re-distill it
anyway but it all comes over at the same temp, down to the last drop. It works great for fischer esterifications, I use it all the time.
I believe certain types of bacteria are used to brew methanol for use in the food industry. I don't know the strain and substrate are, and I don't
know how well saccharomyces cerevesiae would do in a pectin solution by comparison. I've been meaning to experiment...
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unionised
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Why would the food industry want methanol?
If they did, why would they bother to make it rather than just buying it?
Incidentally, I wonder if this whole thread has the idea upside down.
The purity requirements I have for "recreational" alcohol are a lot less stringent than those for lab alcohol (except, perhaps, if you are just using
it for cleaning stuff).
The alcohol I drink is never much better than 40% pure and is full of odds and ends like essence of juniper.
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happyfooddance
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| Quote: Originally posted by unionised |
Why would the food industry want methanol?
If they did, why would they bother to make it rather than just buying it?
|
If it is of biologic origin it can be labeled food grade.
It is mainly used for extractions; although ethanol is more common, sometimes the properties of the smaller alcohol are desirable.
The next big use for food-grade methanol is making artificial flavors. Esters, etc.
The Food Chemical Codex gives specifications for meeting food grade criteria, but the short answer is that if it can be made reasonably pure from
biologic origin, it can be denoted food grade.
http://www.chemceed.com/products/methanol-absolute-fcc-grade...
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markx
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| Quote: Originally posted by blackspirit | | Alongside this what is called hearts, stuff called foreshots, heads and tails are collected and generally form up to 40% of the total distillate,
which is set aside or discarded. |
40% by volume as feints sounds awfully high for a proper column distillation setup.....I usually coast along 10-13% as solvent grade heads+tails
leftovers. It is true, the heads fraction can be very well used for cleaning, disinfection and degreasing of sensitive items. It is also worth noting
that from the initial heads fraction about 50% can be recovered as palatable ethanol in a separate run. The tails from a sugar wash can be harvested
for isoamyl alcohol....it can also be salted out from the tails with saturated sodium chloride solution. For making of some smelly esters or what not
Exact science is a figment of imagination.......
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unionised
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| Quote: Originally posted by happyfooddance | | Quote: Originally posted by unionised |
Why would the food industry want methanol?
If they did, why would they bother to make it rather than just buying it?
|
If it is of biologic origin it can be labeled food grade.
It is mainly used for extractions; although ethanol is more common, sometimes the properties of the smaller alcohol are desirable.
The next big use for food-grade methanol is making artificial flavors. Esters, etc.
The Food Chemical Codex gives specifications for meeting food grade criteria, but the short answer is that if it can be made reasonably pure from
biologic origin, it can be denoted food grade.
http://www.chemceed.com/products/methanol-absolute-fcc-grade...
|
It is only food grade if it meets the requirements stated by some legal authority (which may differ from one country to another).
Provided that it meets those standards it is food grade no matter where it came from.
Methanol made by destructive distillation of wood is unlikely to meet the specifications, even though the origins are biological.
Spectroscopic grade methanol is likely to meet the specifications of a food grade product no matter where it's origins lie.
Are you one of those people who somehow thinks that "natural" = "good"?
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happyfooddance
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Nothing of the sort.
To answer your other question, as to purchasing vs. buying, it is the same practical consideration applied anywhere else: can you make it for cheaper
than you can buy it? If you can, you make it. You might be surprised how many "food processing facilities" make their own HCl, because it is cheaper
than getting it shipped. That and the fact that they already have a lab and a few chemists on staff.
And yes, these things do vary from country, but the FCC is an international organization, like the W.H.O. In the US, the vast majority of vegetable
oil is extracted with hexanes(petroleum origin), because it is cheap and effective, though this practice is banned in the EU. While I don't conflate
"natural" with "good", I do buy expeller pressed oils.
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unionised
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Glad to hear it, but why do you think there's a difference between "of biologic origin " or not?
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happyfooddance
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I don't, but products with biological origin can be sold as "natural", and in many instances the artificial product can not be legally sold as food.
For example, most countries only allow vinegar to be sold for human consumption if it is of biological origin. Acetic acid made from methanol and
carbon monoxide is certainly more pure, and I highly doubt that it would be harmful if used diluted. But that is why.
There is one chemist I know who makes a pretty penny making "natural" flavors... They aren't any more pure, but they are "natural", and he is well
compensated for the extra work.
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Bert
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| Quote: |
The Food Chemical Codex gives specifications for meeting food grade criteria, but the short answer is that if it can be made reasonably pure from
biologic origin, it can be denoted food grade.
|
Could you provide the exact language for that. A good chunk of FCC is enrolled into USA CFRs since 2013? And biological origin is a slippery term,
having little to do with food safety. Curare, strychnine, Botulinum toxin, amanitin...
[Edited on 14-2-2018 by Bert]
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unionised
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Are you aware of this stuff?
https://en.wikipedia.org/wiki/Non-brewed_condiment
It's a mixture of food grade acetic acid with water, colour etc.
It has two merits:
it is cheap
It contains no alcohol and is thus acceptable to some members of religious groups who abstain from alcohol.
You can sell it, but you can't call it vinegar.
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happyfooddance
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| Quote: Originally posted by Bert |
| Quote: |
The Food Chemical Codex gives specifications for meeting food grade criteria, but the short answer is that if it can be made reasonably pure from
biologic origin, it can be denoted food grade.
|
Could you provide the exact language for that. A good chunk of FCC is enrolled into USA CFRs since 2013? And biological origin is a slippery term,
having little to do with food safety. Curare, strychnine, Botulinum toxin, amanitin...
[Edited on 14-2-2018 by Bert] |
I wish I could.
Also, if anyone has more access to FCC entries I would be very appreciative if they would share them with me.
I am very aware that this is a slippery and even dangerous slope!
I am aware of this, but cheap is hardly a merit if you're making/selling it. 
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