I read about butyric acid and was curious about the smell, heard that it smells like vomit or rotten cheese, but wasn't sure exactly what they were
describing so I tried this method for making small amounts of butyric acid for demonstration purposes, you can't get a pure yield but you can just
smell it. Was curious to see what it smells like, which is why I did this.
1. Get one of those small butter packets from fast food stores that looks like this:
2. Add 1/4 of the butter's volume of water with the butter to a metal container for heating.
3. Add NaOH until the butter dissolves into the water. This is saponification: breaks down the fats.
3. After heating to a warm temperature on burner, pour in just a cap-full of sulfuric acid (WARNING: It will splatter and make a steam cloud, but this
cloud also contains the butyric acid)
4. You should smell rotten cheese/vomit after eating fatty foods. Vomit has butyric acid because if you ate food with a lot of fat, it breaks down in
the gut.
[Edited on 12-9-2015 by Cou]fluorescence - 12-9-2015 at 07:43
Shouldn't the longer chain fatty acid sodium salts be less soluble than Sodiumbutyrate ? You could neutralize it to some extent but not convert it
into the free acid. Then, if you work in water some of the longer chain acid salts could perhaps
precipitate leaving you with a much cleaner solution of butyrate and then you continue adding acid to it. 100PercentChemistry - 27-3-2016 at 18:12
I'll see if it works this way. I tried Nile red's method.blogfast25 - 27-3-2016 at 18:47
Shouldn't the longer chain fatty acid sodium salts be less soluble than Sodiumbutyrate ?
Less soluble, yes, but far from insoluble. So it's a poor premise for a separation method.JJay - 27-3-2016 at 19:36
It's going to be hard to do on such a small scale, but fractional distillation of esters might be useful for purification.Zephyr - 27-3-2016 at 19:54
Last summer I collaborated with zts16 and attempted to produce butyric acid. We did this by fermeting ground up potato gunk in large 2L soda
containers, with oxygen traps attached to release the CO2 produced. The slush also contained ~100g of calcium carbonate.
The plan was to produce the soluble calcium butyrate, and then filter to remove the insoluble remnants of the potato gunk. Then we would concentrate
the solution and isolate the butyric acid by treatment with sulfuric acid, removing the insoluble calcium sulfate before distillation.
However, due to the unimaginably terrible stench we had to call it off after acidification.UC235 - 27-3-2016 at 20:08
It's going to be hard to do on such a small scale, but fractional distillation of esters might be useful for purification.
It's doable, but at 3-4% butyric acid content in butter (which also contains proteins and 15-20% water), you'll need to process a ton of butter
biodiesel for significant amounts.
