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mericad193724
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Butyric Acid - Synthesis/Extraction
This is a continuation/deviation of the thread "Science of Vomit" in the miscellaneous forum.
Basically Butyric Acid is responsible for the AWFUL odor of Vomit, rotten cheese, and some other rotten stuff. I would like to make a small amount and
"concentrate" the odor so I can have "AWFUL VOMIT SMELL" in a bottle. Butyric acid is a clear liquid and some members have reported it being really
bad smelling.
Butyric acid can be made through biological process as not_important pointed out...(involves bacteria and days of allowing food to rot - not good on a
humid and hot summer day)
I would like to take a chemical approach to making or extracting butyric acid...Wikipedia says that butter contains 3-4% in the form of esters.
Wikipedia also says...
"When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis leading to the unpleasant odor."
So...if I take butter from the fridge and add NaOH to do the hydrolysis (sort of like making biodiesel) ...I should get an AWFUL smell which should be
the butyric acid liberated.
If this makes sense please tell me and I will go try this. Step two would be extracting/purifying it.
If anyone can find the synthesis of butyric acid it would be really appreciated
thanks
Mericad
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not_important
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Saponifying butter will give you sodium butyrate along with a mix of the soium salts of other fatty acids. The salts don't have much smell. Treating
those with a mineral acid will give you a mix of those fatty acids, some 7 to 10 percent of the total are the shorter smellly ones - butyric, caproic,
caprylic, capric (cap- referes to goats, city folk may not get the drift). But the rest is the longer chain acids, which become more and more 'fatty'
in smell.
You can distill the mix to concentrate the shorter chain acids, remember that a kilo of butterfat will give you 30 grams or so of butyric acid. Steam
distillation also works, although not as cleanly it's good for getting the acids out of the reaction mix.
Do distillation out of doors, away from other people.
The Favorskii rearrangement of monohalogenate metyle ethyl ketone gives isobutyric acid, I think; it will be that or normal butyric, iso is smelly
too.
The classical route is to react 1-bromopropane with NaCN, the hydrolise the nitrile.
The fermentation route has the advantage of using sugar, chalk, and a bit of milk and cheese; all are easy to get and certainly OTC.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/1bioche...
[Edited on 8-8-2006 by not_important]
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unionised
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Just a thought, you could sub-distill the volatile fatty acids.
Hydrolyse some butter and acidify it to get the mixed acids. The ones you want are the volatile ones (at room temp). Place the acids in a tray like
container with some sodium hydroxide solution round it inside a bigger container (a desiccator with a couple of petri dishes would be ideal). Wait a
while. All the volatile acids will diffuse into the NaOH soln and be converted into involatile salts. After this process has finished acidify the NaOH
soln to free up the acids.
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Elawr
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If you happen to be near any Ginkgo trees, you can try isolating butyric acid from the fruit. Only the female trees bear fruit, which looks kind of
like a date and is very stinky. It is said these fruit are rich in butyric acid. The species is Ginkgo bilboa, native to China, but planted generally
everywhere as an ornamental shade tree.
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hodges
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I don't know if this would work but it is possible. Fill a clear container most of the way with butane gas. Add a small amount (10%?) of chlorine
gas and expose to sunlight. Upon adding water or weak NaOH to this you should get some butyl alcohol. This could be oxidized using say KMnO4 to
butyric acid.
I'm sure yields would be low but I wouldn't be surprised if they were enough to detect the odor.
Hodges
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The_Davster
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n-propyl bromide could also be used to make a grignard, then treat with CO2.
EDIT: Yes, of course, propyl not butyl, I had the oxidation of n-butanol in mind as well as I posted.
[Edited on 9-8-2006 by rogue chemist]
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not_important
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n-propyl, not n-butyl. Kind of a waste of Mg, I think. Sugar is way cheaper and easier to get.
Bottled butane is often (usually?) a mix of n- and iso- butane, so you will get sec- and tert- butyl halides as well. Doing the reaction in sunlight
will help move towards statistical ratios of substitution, helping get n-butyl. Using a large excess of butane helps keep down the amount of
polysubstituted butanes. Water and NaHCO3 works well to get the t-butyl halide to the alcohol, allowing that to be separated from the other isomers
(I think some of the sec-butyl will hydrolise as well); the remaining organic layer could then follow Hodges route.
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Shadowcaster
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Emm... IIRC GABA is readily available as a nutritional supplement in a lot of parts of the world. How about doing a Sandmeyer-Reduction (1. NaNO2 +
HCl 2. H3PO2)?
Peace out,
Lord Shadowcaster
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not_important
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| Quote: | Originally posted by Shadowcaster
Emm... IIRC GABA is readily available as a nutritional supplement in a lot of parts of the world. How about doing a Sandmeyer-Reduction (1. NaNO2 +
HCl 2. H3PO2)?
Peace out,
Lord Shadowcaster |
Doesn't work well with aliphatic amines, when dioatized they give a mix of alkane, alkene, alcohol, dimers, and worse.
This was more to come up with alternatives, especially OTC ones. While GABA cuurently falls under that classification, it may not stay there; NaNO2
is not truely OTC and H3PO2 certainly is not. GABA and H3PO2 are rather expensive, if you have access to NaNO2 and H3PO2 then it would be likely you
hace access to butyric acid as well.
[Edited on 16-8-2006 by not_important]
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mericad193724
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I would like to get back on track with my attempted butyric acid synthesis. I want to make butyric acid so I can make all those cool esters such as
butyl butyrate- pineapple....ethyl butyrate-banana...methyl butyrate and more! (If you haven't noticed my other running thread is about sulfuric acid
production so I can make esters.)
I think I found an easier, non-biological way to make butanol which can be converted to butyric acid by an oxidizing agent.
Wikipedia claims Butanol can be made from electrolysis of Ethanol...
C2H5OH + C2H5OH → C4H9OH + H2 + 1/2 O2
I have some ethyl alcohol I distilled but it contains about 15% acetone in it since they seemed to form some sort of azeotrope, I can't separate them.
Butanol can be distilled off at 117C and the excess ethanol would come at 78C. Does this seem possible???
Would the acetone denaturant in my ethanol make any resulting compounds under electrolysis that could interfere with making or distilled butanol?
thanks
Mericad
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Eclectic
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Butyl acetate is available as a paint thiner. You can get n-butanol from that and oxidise it to butyric acid.
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Pyrovus
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One potential problem with electrolysis of ethanol is that it might produce significant quantities of diethyl peroxide, by something like the
following:
2C2H5OH + 2e- -> 2C2H5O- + H2
C2H5O- -> C2H5O. +e-
2C2H5O. -> C2H5OOC2H5
I don't know how much would be produced (perhaps I'm just being paranoid here), but if any significant amount of Et2O2 is formed it could pose an
explosion hazard.
[Edited on 7-11-2006 by Pyrovus]
Never accept that which can be changed.
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fractional
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There is an easy way to produce esters of butyric acid without having to use the butyric acid itself, which is a truly awful chemical to work with:
transesterification.
You mix one ester of butyric acid with a different alcohol, add some sulfuric acid and cook for a short while. The end result is a mix containing the
"new" ester of butyric acid. Example: methyl-butyrate + ethanol + sulfuric acid -> ethyl-butyrate + methanol
This is an equilibrium reaction and the yield depends on how well you can remove the products from the mixture by e.g. destilling them off, with other
words on the difference in boiling points. Depending on the reactants the yield can also be improved in the usual manner by using a surplus of
alcohol.
I have once tried butter as starting material and cooked it with ethanol and some sulfuric acid. The results is a mix of different sweet and fruity
smelling ethyl esters of the short fatty acids contained in the butter, including butyric acid, which can be easily destilled off from the
longer-chained esters. Obviously you don't get a pure product, at least not in this step. Different alcohols will of course produce different esters.
As mentioned in a previous post the yield is not very high since butter only contains about 10% or less of short fatty acids (C4...C10), but it is
easy and very cheap.
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fractional
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I forgot to metion: butter always contains some water, which can be removed by heating up the butter and only using the oily upper layer. Water-free
(or rather water-reduced) butter will give better yields.
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BeerChloride
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I just tried a quick-and-dirty plow through using butter. I took a gram of butter, added some water and some NaOH and heated for 5 minutes with
propane. Then I cooled it and strained out the solidified fats. I added some H2SO4 to the aqueous and took a whif.  Am unhappy to report a positive result for vomitacious odor. It made my stomach queasy: I just ate a bunch of macaroni
and cheese, too. Hmm, sniffing that did something to my stomach..
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jimmyboy
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what is sodium butyrate insoluble in? tce/chloroform/alcohol? would like to precipitate it
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BeerChloride
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Ok, here's my guess: any organic solvent used to ppt sodium butyrate would likely ppt out the inorganic salts, if not more so. I can understand why
you want to keep the butyrate as a salt, but acidifying and extracting the acid seems much more straightforward. The acid could be extracted with
ether, or can be salted out of solution with calcium chloride.
Unionized had an interesting idea (acidify, then leave in dessicator with NaOH). I suppose bicarbonate could be used, then a simple water extraction
should give a high ratio of sodium butyrate in solution since bicarbonate isn't very soluble.
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jimmyboy
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yeah - isolating the salt would be alot more friendly by far -- i guess your just stuck with fractional distilling the acid (in a barn.. in another
county hahaha) - at least the synth is fairly easy
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pantone159
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The transesterfication with butterfat and ethanol is indeed fun, I got some very pineapple-smelling liquid out of it.
This link describes the prep that I mostly followed.
http://yarchive.net/chem/pineapple_synthesis.html
It is best to used 'clarified butter'. (Google this and you'll find lots of cooking pages that describe this.) Butter is composed mainly of
butterfat, water, and some milk stuff (forget exactly what). Basically, you slowly boil butter until all the water evaporates. The milk stuff then
coagulates into a solid, which you remove by filtration, leaving 'pure' butterfat. (Not a pure compound though.) This stuff keeps well, I have some
that has been stored at room temp for 9 months and is not rotten.
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mericad193724
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Thanks for all the ideas everyone and BeerChloride I appreciate you trying out the butter method, it must have been an...umm...interesting smell .
I am not sure that extraction from butter is as straightforward as it sounds. Someone mentioned that there are a lot of other esters in butter,
butyric being a very small percent. I would probably be difficult trying to separate the butyrate from the rest of the esters and organic crap.
Pyrovous brought up a good point that diethyl peroxides can be formed in electrolysis of ethanol. I would like to attempt electrolysis but want to
make sure it is safe. Can you add something OTC to the liquid to prevent the formation of peroxides. I think you do something like this when working
with ether.
I heard copper wire would do the trick. What works? Copper? MnO2? Iron? Suggestions would be really appreciated.
thanks
Mericad
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pantone159
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| Quote: |
I am not sure that extraction from butter is as straightforward as it sounds. Someone mentioned that there are a lot of other esters in butter,
butyric being a very small percent. I would probably be difficult trying to separate the butyrate from the rest of the esters and organic crap.
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I think the small ones might react faster, so you get a higher percentage of the small esters than in the original butterfat. I thought I got good
results doing this, the result has a good pineapple smell. I'm sure it is not pure, but it was a cool experiment anyways.
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not_important
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| Quote: | Originally posted by mericad193724
I am not sure that extraction from butter is as straightforward as it sounds. Someone mentioned that there are a lot of other esters in butter,
butyric being a very small percent. I would probably be difficult trying to separate the butyrate from the rest of the esters and organic crap.
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That was me, 3 to 4 % in butter fat. However the next acid is two carbons larger, the esters boil far enough apart that a simple fractionation will
give decent separation of butyric from the rest. There are other, non-acid compounds, true. If you want really clean butyric then hydrolyze, extract
with a fairly non-polar solvent to remove non-salts, acidify and make the methyl or ethyl ester.
| Quote: |
Pyrovous brought up a good point that diethyl peroxides can be formed in electrolysis of ethanol. I would like to attempt electrolysis but want to
make sure it is safe. Can you add something OTC to the liquid to prevent the formation of peroxides. I think you do something like this when working
with ether.
I heard copper wire would do the trick. What works? Copper? MnO2? Iron? Suggestions would be really appreciated.
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I don't think those work with fully peroxides, just with hydroperoxides ( ROOH ), but I could be wrong. Clean iron wire was a traditional
anti-peroxide trick for ether.
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fractional
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In the original "Science of Vomit" thread not_important mentioned another method to produce butyric acid, that of fermentation of natural substances.
There is one recipe in Vanino (Praeparative Chemie Vol. 2). He uses 100 g of potato starch dissolved in 2 litres of water at 40 degC, plus some
fertilizer for the bacteria (see below): 0.1 g potassium phosphate, 0.02g magnesium sulfate, 1g ammonium chloride. 50g of calcium carbonate are also
added.
A bacterium culture is prepared by soaking a handful of hay in 0.25l of 36 degC water for 4 hours. The liquid is then decanted and filtered and boiled
for 5...15 minutes. This kills all harmful spores and bacteria, but not the spores of the "useful" bacterium (Bacillus subtilis)for butyric acid
fermentation.
The culture is added to the solution of starch, which is then fermented by keeping it at 35...40 degC for about 10 days. The smelly product is then
filtered, made slightly acidic and destilled. Yield in Vanino is 34.7g butyric acid and 5.1g acetic acid. Boiling point for n-butyric acid is 162.3
degC.
The advantage of this method is a rather good yield (35g of butyric acid out of 100g of starch) using dirt cheap materials. Of course this requires
the handling of rather large quantities of smelly liquid and the need to keep it warm for 10 days or so.
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JohnWW
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Once having obtained butyric acid or its esters or salts, how would one convert it to 1,4-n-butanediol, or to GHB? The main problem seems to be that
the smell of the stuff may give the game away.
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mericad193724
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Thanks for the procedure fractional. I think I might try it. I can do the actual fermentation process in a 2L soda bottle.
Just a few questions first....
Isn't calcium butyrate soluble in water?...this would make the procedure sort of difficult having to distill two liters of the liquor. Any substitutes
for potato starch, I don't think it is in the supermarket, but I do have corn starch.
How about trisodium phosphate instead of potassium phosphate?
By the way, my electrolysis of ethanol to make butanol failed, it should have released gas from the electrodes but it didn't, nothing happened, I used
6V at 10amps, could it be that the voltage is not high enough to do the job or is it not conductive enough(add a salt?)?
Thanks a lot
Mericad
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