Sciencemadness Discussion Board - Butyric Acid - Synthesis/Extraction

Butyric Acid - Synthesis/Extraction

mericad193724 - 8-8-2006 at 07:11

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

not_important - 8-8-2006 at 07:38

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]

unionised - 8-8-2006 at 09:03

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.

Elawr - 8-8-2006 at 11:24

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.

hodges - 8-8-2006 at 15:45

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

The_Davster - 8-8-2006 at 15:56

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]

not_important - 8-8-2006 at 16:38

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.

Shadowcaster - 15-8-2006 at 20:40

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

not_important - 15-8-2006 at 21:33

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]

mericad193724 - 6-11-2006 at 15:17

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

Eclectic - 6-11-2006 at 20:44

Butyl acetate is available as a paint thiner. You can get n-butanol from that and oxidise it to butyric acid.

Pyrovus - 6-11-2006 at 23:57

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]

fractional - 7-11-2006 at 01:29

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.

fractional - 7-11-2006 at 01:45

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.

BeerChloride - 7-11-2006 at 02:19

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..

jimmyboy - 7-11-2006 at 04:59

what is sodium butyrate insoluble in? tce/chloroform/alcohol? would like to precipitate it

BeerChloride - 7-11-2006 at 05:48

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.

jimmyboy - 7-11-2006 at 09:31

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

pantone159 - 7-11-2006 at 11:28

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.

mericad193724 - 7-11-2006 at 13:24

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

pantone159 - 7-11-2006 at 22:00

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.

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.

not_important - 7-11-2006 at 22:30

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.

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.

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.

fractional - 16-11-2006 at 05:23

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.

JohnWW - 17-11-2006 at 14:02

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.

mericad193724 - 18-11-2006 at 13:01

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

roamingnome - 18-11-2006 at 14:42

while skimming the post here saw the,

butanol from electroysis of ethanol. just was looking into that elsewhere as a substatute for octanol which is hard to come buy unless you have coconuts laying around...

anyway theres no excuse for exspirmentation on my part but what do you recomend put some electrodes into ethanol?, or is there some pH issue or secrete acetate ion to add.. i cant seem to find any solid refs on it....

fractional - 19-11-2006 at 04:39

@mericad193724
The procedure worked for me, but it shows the disadvantages of following " cooking-book recipes": I don't know exactly why. I got a slightly lower yield, but I think that's due to the fact that I did not have a 4l RBF, so I had to distill in several batches. The original recipe did not give any explanation or rationale beyond the bare steps, but here are some thoughts:
As for the " fertilizer" I believe any phosphate salt will do. The phosphate is after all the nutrient needed by the bacteria. The addition of calcium carbonate was a mystery to me until wikipedia told me (under "butyric acid") that there are strains of bacteria that start producing acetone rather than butyric acid if the pH gets too low (<= 5), so an alkaline must be added. I also think that calcium butyrate will be formed, but before the destillation the liquid must be made slightly acidic (I used diluted HCl), which helps releasing the butyric acid. The difference in boiling points makes the destillation rather easy, but I used a short colum nevertheless.
As for any fermentation cleanliness is very important. I desinfected all the gear before use and it worked out ok.

No experience with the electrolysis of ethanol to get butanol, but I'll see what I can find in the literature. 10A at 6V looks plenty to me, though. I don't think the problem lies there.

mericad193724 - 19-11-2006 at 08:33

Thanks for all the help fractional...I found the ethanol electrolysis problem...the liquid is not conductive! I feel like an idiot

! I used my multimeter and I got a reading of around 200K ohms, I had less than a 1 milliAmp flowing! Now all I need to do is make it very conductive and I will try again. What should I add that will not effect the final product or react with it? CaCl2 is soluble in ethanol, but won't that form CaOH? My electrochemistry knowledge is close to zippo.

Could someone please give me some advice or adding some kind of electrolyte to ethanol so I can make Butanol.

I could run the cell tonight

Mericad

fractional - 20-11-2006 at 06:11

I did some research on the electrolysis of ethanol to get butanol with close to zero result. Lund, " Organic Electrochemistry" hints at an "electroenzymatic" production of butanol: a bit exotic, I think. Loeb, " Electrochemistry of organic compounds" mentions butanol as a rather insignificant by-product of other reactions. Bochris " Modern Electrochemistry", a more recent book, says nothing.
Wikipedia does not give a reference, not uncommon, but rather annoying, all the same.
So I have no idea where this reaction comes from and personnally I would not give it much hope. Worth trying, nevertheless, because it's so simple. You can try in acidic or alkaline conditions. The results will be different for the two setups! Sulfuric acid and HCl are used to acidify. "A little alkali" (Loeb) to do the opposite. Potassium acetate was used to increase the conductivity of pure alcohols without changing the pH.

[Edited on 20-11-2006 by fractional]

mericad193724 - 24-11-2006 at 14:53

I added NaOH to alcohol but couldn't dissolve enough to make it very conductive. I don't want to use an acid like Sulfuric acid so I won't make Diethyl Ether and get the peroxides as well

! If it was so easy to make butanol by electrolysis, it probably would have been very well documented and known, so I am assuming it is hard.

I know you can convert Butanol --> Butyric Acid, but can you convert Butyric acid --> Butanol???

Butanol has low solubility in cold water so if we can change the butyric acid in the fermentation to butanol, separation would be very easy! No need to distill 2L!

Mericad

Random - 9-11-2010 at 08:24

I took like 1 kg of very ripe ginkgo fruit that smelled bad (so thats good). I squeezed the juice out of them, then filtered it few times (juice didn't smell so bad or I started to like butyric acid smell?). After that I put ca(oh)2 in it. The smell disappeared. After that I put HCl in it and there started to form some insoluble particles floating on top, yellow and orange separated pieces, some were big as 1.5 cm. MAybe there is now oily layer, but I didn't check, but from top, the solution smells bad when wind blows it into my nose

What are those insoluble particles and should there be butyric acid salted out as oily layer? (maybe I didn't notice it immediately because of those particles.)

The WiZard is In - 9-11-2010 at 09:22

Quote: Originally posted by Random

What are those insoluble particles and should there be butyric acid salted out as oily layer? (maybe I didn't notice it immediately because of those particles.)

30 Minutes in the libary (or 2.4 seconds on la net) can often
save 30-days in the lab.

Ginkgo biloba
Teris André van Beek

Provides a ref to a publication of the putrid aroma compounds
from GB.

Think butanuic (butyric) & hexanoic (caproic) acids.

Parts of la book can be read at the usual URL place.

Ginko fruits always smelled like old socks to me.

[442]
ANNUAL REPORT SMITHSONIAN INSTITUTION, 1938
GINKGO BILOBA
MAIDENHAIR TREE SEWARD

Male and female reproductive organs are borne on separate trees. It is possible to obtain both kinds of "flower" on one tree by grafting a female branch on to a male tree: this operation was successfully performed some years ago on the large male tree at Kew. My friend the Rev. Prof. A. C. Moule of Cambridge, tells me he discovered a passage in an old Chinese book advising the planting of female seeds close together in order to ensure fertilization at a later stage. This implies an uncanny power of distinguishing female even in the seeds. The male flowers as it is convenient to call the reproductive shoots are loose catkins bearing on a slender axis several short stamens, each of which has two or rarely three or even four pollen sacs. The female shoots are longer and la usually bearing a pair of ovules which develop into fleshy yellow seeds as large as cherries. In the Far East the maidenhair tree of as the silver apricot. Within the fleshy covering a hard shell, generally with a prominent median keel, encloses and protects the embryo and the store of food prepared by parent for offspring. The kernel (embryo and food) is eaten in China and Japan as a delicacy: the outer flesh is nauseous.

----------
Srurtevant’s Edible Plants of the World 1919
Dover Reprint

Ginko biloba Linn. Coniferae. GINKO. MAIDEN HAIR TREE.
China and Japan. The fruit of the ginko is sold in the markets in all Chinese towns and is not unlike dried almonds, only whiter, fuller and more round. The natives seem very fond of it, although it is rarely eaten by Europeans.(7) In Japan, the seeds furnish an oil used for eating and burning. (8) The fruit of the maiden hair tree is called in China pa kwo. The Chinese consume the nuts of this tree at weddings, the shells being dyed red; they have a fishy taste. (9) This tree is largely cultivated as an ornamental in Europe, Asia and North America.

7 Fortune,R. Wand.China 118. 1847.
8 Pickering,C. Chron.Hist.Pls. 797. 1879.
9 Smith, F. P. Contrib. Mat. Med. China 103. 1871

eaten in China and Japan as a delicacy... well
the French eat each other so who am I to criticize?

Random - 9-11-2010 at 11:21

But butyric and caproic acids have melting point of -7 and -2 celsius degrees, so it should be oily layer then and not insoluble solid particles floating on top. I don't think butyric acid should look like that, or is that actually oily layer?

Random - 12-4-2011 at 13:01

I left that jam jar with all that ginkgo stuff outside during the winter until now. It looks I got some success.

Today I checked the solution, it smelled like a successful reaction. I saw some brown stuff at the bottom (it could be some iron oxides because of the jam jar cap and some stuff from ginkgo which was destroyed by HCl during few months). But, there was something more interesting. I think I noticed very thin like 1.5-2mm colorless layer on that brown solution which is floating like oil. It was in smaller jam jar bottle so up to the lid so I transferred it then into a bigger one. Everything mixed so I think I need to leave it until tomorrow to break the emulsion. Maybe there is even more butyric acid in solution, because I did this:

Extracted the ginkgo juice, filtered it and added Ca(OH)2.
Added HCl to make it highly acidic. This made some CaCl2 to salt out butyric acid from the solution, though maybe not everything what's in is salted out. Maybe saturating it with NaCl would make it more insoluble if there is more.

12332123 - 13-4-2011 at 09:53

Is the subtilis fermentation aerobic or anaerobic?

[Edited on 13-4-2011 by 12332123]

mario840 - 9-6-2011 at 04:37

Hydrolize acid chloride like butyryl chloride (cheap) with water in the present of base like pyridine or NaOH to consume evolving HCl

redox - 9-6-2011 at 12:06

If you want butyric acid, take 1-butanol, which is common, and oxidize the s**t out of it!

Try jones' reagent (dichromate + acid + acetone), or alkaline potassium permanganate. When you smell the tell-tale smell, you're done!

mario840 - 9-6-2011 at 12:49

The easiest, cheapes method is what redox said , Jones will do job but hot alkaline solution of KMnO4 too ! but it's not carcogenic like Jones

not_important - 9-6-2011 at 13:12

Another low cost method, discussed several times on other threads, is NaOCL bleach plus a nickle salt as catalyst. You get a solution of the acid as its sodium salt, plus NaCL, with the nickle as insoluble oxides which are easily filtered off and converted back to NiCl2.

blogfast25 - 10-6-2011 at 12:47

Quote: Originally posted by not_important

Another low cost method, discussed several times on other threads, is NaOCL bleach plus a nickle salt as catalyst. You get a solution of the acid as its sodium salt, plus NaCL, with the nickle as insoluble oxides which are easily filtered off and converted back to NiCl2.

Yes, I remember you advising nickel salt + hypochlorite to ‘break’ the emulsion of a zirconium containing roll on anti-perspirant. I didn’t have any nickel but I have now…

For the oxidation of n-butanol this way, do you have anything resembling a recipe? And should this also work with iso-amyl alcohol (3-methyl butan-1-ol)?

In that reaction the ClO- is reduced to Cl-, right? Wouldn’t that require ridiculous volumes of commercial bleach, given how dilute the latter is and (at least!) two ions of hypochlorite per molecule of alcohol?

not_important - 11-6-2011 at 14:36

Quote: Originally posted by blogfast25

...

For the oxidation of n-butanol this way, do you have anything resembling a recipe? And should this also work with iso-amyl alcohol (3-methyl butan-1-ol)?

In that reaction the ClO- is reduced to Cl-, right? Wouldn’t that require ridiculous volumes of commercial bleach, given how dilute the latter is and (at least!) two ions of hypochlorite per molecule of alcohol?

http://www.sciencemadness.org/whisper/viewthread.php?action=...

The JOC article there reports isbutyric acid from the alcohol with an isolated yield of 89%, neopentyl alcohol to the acid with 88% isolated, n-octanol to the acid at 68% isolated.

Yeah, it's not real concentrated. But you can extract, or acidify then steam distill an acid-water mix for the more volatile acids, or make sure the solution is alkaline (NaHCO3 or Na2CO3) then evaporatively concentrate followed by acidification and extraction or steam distillation. Bleach can be had cheaply if you look a like, or wait for sales. Common bleach is 0.8 to 0.9 M, so it does take a bit of it but the OTC nature and cheapness makes up for that.

blogfast25 - 12-6-2011 at 05:03

Quote: Originally posted by not_important

Quote: Originally posted by blogfast25

Thanks! I wonder if it would work on that vinyl-gloves-extracted 2-ethyl hexan-1-ol,,,

Globey - 17-6-2011 at 07:57

Isn't butyric acid used by all the pro lifers?! You don't want to use the same foul shi as them, do you?! Besides, although I think butyric acid does indeed smell foul, I think methyl mercaptan smells like a pepporoni and meat sub which Tony Soprano ate too fast, and is therfore bein anaerobically fermented in his intestines, and results in a deadly fart. Seriously. I have smelt both. It is far worst.

not_important - 17-6-2011 at 10:14

Quote: Originally posted by blogfast25

...
Thanks! I wonder if it would work on that vinyl-gloves-extracted 2-ethyl hexan-1-ol,,,

Should, given that they reported the yield for n-octanol. Clean-up likely requires extraction with aqueous alkali from something like DCM or toluene to separate unreacted alcohol from the acid, then regeneration of the acid.

nb198 - 28-6-2014 at 02:48

I tried the synthesis using KMno4 and it worked!

I made a video on it: https://www.youtube.com/watch?v=M8VSKqPYdHI

blogfast25 - 28-6-2014 at 06:18

Nice work, nb198! Good video too. Even yield wasn't too shabby. But it does take the patience of an angel, this method...

So are you going to make some pineapple flavoured ester with it?

How bad does this pure butyric acid really smell?

Wouldn't the oxidation proceed more quickly in acid conditions? The formed Mn2+ could be precipitated as Mn(OH)2 (which fairly quickly oxidises to MnO2 anyway) with NaOH, which would also form sodium butyrate. From there on the work up would be very similar...

[Edited on 28-6-2014 by blogfast25]

Magpie - 28-6-2014 at 11:13

Very nice work, showing good technique and excellent purity of product! I take it that you were using university facilities?

nb198 - 2-7-2014 at 05:56

Quote: Originally posted by blogfast25

Nice work, nb198! Good video too. Even yield wasn't too shabby. But it does take the patience of an angel, this method...

So are you going to make some pineapple flavoured ester with it?

I don't plan to makes esters with it actually. I am going to keep the stinky concoction!

I honestly don't think it smells that bad. For some reason, bad smells don't affect me too much though. Coworkers think it's awful, but I don't mind it.

nb198 - 2-7-2014 at 05:59

Quote: Originally posted by Magpie

Very nice work, showing good technique and excellent purity of product! I take it that you were using university facilities?

You are right. I work in a university lab as a technician. Unfortunately, this is only for he next 2 days, as I will be leaving. So some future videos might be in a ghetto home lab. Until I return as a grad student

Newton2.0 - 4-2-2021 at 14:46

What is the procedure for isolating butyric acid from a solution? I had performed a Sandemeyer reaction to produce GBL and I wanted to extract the butyric acid and then purify it to at least 95%.

I have seen people discuss salting it out of solution then collecting the oil fraction and purifying by distillation.

I'm having trouble finding a procedure for isolating butyric acid. Thanks!

draculic acid69 - 12-2-2021 at 01:38

Quote: Originally posted by mario840

Hydrolize acid chloride like butyryl chloride (cheap) with water in the present of base like pyridine or NaOH to consume evolving HCl

Without buying butyryl chloride from you or China or Sigma Aldrich (@10x the price)
where would one aquire this cheap acyl chloride?