Synthesising butyric acid for a home esterification experiment

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username5154386
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Hey guys,
I've been working on this project for a while now (4 weeks? Idk maybe a bit less). What I was looking for is to recreate an esterification reaction we did at school that didn't really work (I am in Year 12, doing Further Maths, Physics and Chemistry). So yeah, but the problem is some substances like butanoic (butyric) acid can only be purchased from school lab suppliers and I really can't do that.

So after researching (I found like 10 different sources and bookmarked them automatically), what I did is I tried to ferment rancid butter, parmesan cheese and sour milk together in an air-tight jar in order to allow obligate anaerobic bacteria to ferment the aqueous mixture. I waited about a week and a half then added extra sugar and some more smelly cheese. When it's sunny it seems to be working faster but I don't know. Anyway my idea so far is to open the jar after about 2 weeks, extract the butyric acid by filtering the mixture through some cotton repeatedly, removing the big creamed fat layers formed each time and redoing it etc. until I end up with a smelly colourless liquid. I really, really did my mining for this project on the internet and it seems like most folks think distillation is best for purifying the acids, but obviously I only have one kettle and I really don't appreciate the idea of distilling butanoic acid in a kettle that's used by family for tea. So I think I am gonna stick to filtration...
BTW speaking of kettles, I thought I might just be able to extract enough calcium carbonate from the limescale layer formed in the bottom of the kettle for it to be able to undergo a displacement reaction with dilute hydrochloric acid and form calcium chloride? Because calcium chloride is very soluble in cold water and it can help to remove water from the final aqueous butyric acid solution. But at the same time, I really don't want to use the limescale-removing agents as then I would be introducing more chemicals which is literally the last thing I want to do...
So do you reckon filtering it through cotton several times then using a DIY separatory funnel to remove any remaining layers of stearic / oleic / linoleic acid could work?
Also, I know that C. Acetobutylicum switches to a metabolic path that makes butanol and acetone instead of butyric acid if in more acidic condition (pH < 5). But that's not necessarily a problem for me I think because I don't think it's gonna reach that pH and also because for my purposes, I don't need a high level of purity. In fact butanol being produced could be a good thing because my project deals with making esters and having some butanol would just mean that I end up producing butyl butyrate in the final esterification reaction, which smells of strawberry / pineapple (just like my desired product).

Yeah, I also found that I have some white distilled vinegar at home as well as salicylic acid and lactic acid medicine for acne treatment. So I managed to separated the salicylic acid ( i think?) because I want to make ethyl salicylate (wintergreen. methyl salicylate is better but i don't have methanol) and ethyl acetate as well as ethyl butyrate.

As for the Fisher esterification reaction itself, I've prepared some sodium carbonate solution by thermally decomposing baking soda (sodium bicarbonate) in boiling water (just didn't have a bunsen burner so i had to do it this way). That reaction definitely went well because lots of CO2 and water was given out. I calculated the amounts needed roughly for 0.5 M solution of sodium carbonate, which I'll use to form the ester layer in the end (remove any acid catalyst residues)
But the thing is, I haven't bought any acid yet. Do you reckon hydrochloric acid will work? I don't have sulfuric acid lol, no way. I'd only really imagine that batteries might contain sulfuric acid but no way I am handling that stuff- way too dangerous.
The only problem is there's no way on earth i can procure industrial muriatic acid. The only option available at the moment is to use dilute hydrochloric acid from over the counter in hardware stores, at concentration of about maybe 20 ppm max. Do you think if I just use x10 the meal of dilute hydrochloric acid on the expense of less water in the actual esterification then it would be equivalent to a catalytic amount (2 drops of concentrated hydrochloric acid?). Also, if it is enough, do you think that warming some ethanol in a hot water bath for about 5 minutes would work? (i have plenty of 75% concentrated ethanol for hand sanitising purposes so it's fine) would do the trick?

Hey, I appreciate this is a really really long procedure ( I guess if it doesn't work I should just try making some ghee and working upwards from there). But can anybody confirm / debunk any piece of this procedure?
THANK YOUUUUUUUU in advance!!
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Sophhhowa
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I wouldn’t advice trying to do chemistry experiments at home as it can be incredibly dangerous
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username5154386
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(Original post by Sophhhowa)
I wouldn’t advice trying to do chemistry experiments at home as it can be incredibly dangerous
Hey
It's not at home, it's at the garden
I just call it home experiment because I am not using school apparatus
The only source of danger I detected in my risk assessment is the butyric acid itself. But I have gloves and goggles so it's okay. And the hydrochloric acid is probably gonna have a concentration of 10% max.
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Sophhhowa
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(Original post by Dr Sarkis)
Hey
It's not at home, it's at the garden
I just call it home experiment because I am not using school apparatus
The only source of danger I detected in my risk assessment is the butyric acid itself. But I have gloves and goggles so it's okay. And the hydrochloric acid is probably gonna have a concentration of 10% max.
I still really wouldn’t recommend such as complicated experiment without the supervision of someone qualified and with appropriate equipment. If you want to get a better feel/ understanding of the experiment then watch a teacher doing it on YouTube. Sorry but I strongly believe you are putting yourself in unnecessary risk by doing this in the garden
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username5211340
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Do not attempt to do this experiment at home. It will be extremely dangerous.
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errrr99
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(Original post by Dr Sarkis)
Anyway my idea so far is to open the jar after about 2 weeks, extract the butyric acid by filtering the mixture through some cotton repeatedly, removing the big creamed fat layers formed each time and redoing it etc. until I end up with a smelly colourless liquid. I really, really did my mining for this project on the internet and it seems like most folks think distillation is best for purifying the acids, but obviously I only have one kettle and I really don't appreciate the idea of distilling butanoic acid in a kettle that's used by family for tea. So I think I am gonna stick to filtration...
truthfully I love your idea but I think you might retch too much each time, it's going to be difficult to tolerate unless you cannot smell at all (covid symptoms).

Also if all the internet says distillation is required, then it really is required...you must know someone with an old kettle, try asking around? people leave old pots and pans outside for collection, keep your eyes peeled

anyway good luck!
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username5154386
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(Original post by errrr99)
truthfully I love your idea but I think you might retch too much each time, it's going to be difficult to tolerate unless you cannot smell at all (covid symptoms).

Also if all the internet says distillation is required, then it really is required...you must know someone with an old kettle, try asking around? people leave old pots and pans outside for collection, keep your eyes peeled

anyway good luck!
You're absolutely right, I should find a kettle...
Haha no, it's fine, I've been allergic for the last 5 years and so I can barely smell anything.. It's nothing to do with SARS-CoV-2 but hopefully I can still get this experiment done before a neighbour will have any complaints...
About the time consumption? Yes, I thought about it and if it doesn't work (which it is pretty much guaranteed to not), then I'll just purify my own ghee as and try separate butyric acid from that.
Water has a boiling point of around 100.0 °C whilst butyric acid has a boiling point of about 163.5 °C. So it should be no problem to just boil the water by repeated heating! I'd say there's plenty of kettles that can get there, but anyway most water particles will probably evaporate way before that.
I just need to get the delivery tube done and some icepack.
Thank you ^_^
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username5154386
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(Original post by Sophhhowa)
I still really wouldn’t recommend such as complicated experiment without the supervision of someone qualified and with appropriate equipment. If you want to get a better feel/ understanding of the experiment then watch a teacher doing it on YouTube. Sorry but I strongly believe you are putting yourself in unnecessary risk by doing this in the garden
I'm getting supervision, my dad said he'll do anything that deals with adding the hydrochloric acid. I also have gloves and specs in case I haven't mentioned. I asked my chemistry teacher to confirm if my method is alright.
Also, I've never "watched" somebody doing it on YouTube as such, it's a procedure I pretty much made up from sticking bits and pieces of things I found on the Internet and some common sense. The main part of it is just esterification, which I've watched countless tutorials about how to do them. The fermentation part has also been a big part of my searches. The filtration methods and the ideas for purifying it are from Wikipedia and from NileRed. I've used WikiHow extensively for all the steps.
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Sophhhowa
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(Original post by Dr Sarkis)
I'm getting supervision, my dad said he'll do anything that deals with adding the hydrochloric acid. I also have gloves and specs in case I haven't mentioned. I asked my chemistry teacher to confirm if my method is alright.
Also, I've never "watched" somebody doing it on YouTube as such, it's a procedure I pretty much made up from sticking bits and pieces of things I found on the Internet and some common sense. The main part of it is just esterification, which I've watched countless tutorials about how to do them. The fermentation part has also been a big part of my searches. The filtration methods and the ideas for purifying it are from Wikipedia and from NileRed. I've used WikiHow extensively for all the steps.
You’re dad cannot be qualified because if he was he would NOT let you do this. DO NOT CARRY OUT THIS EXPERIMENT UNLESS YOU ARE IN A LAB USING AN APPROVED METHOD AND PROPER EQUIPMENT UNDER THE SUPERVISION OF YOUR TEACHER! I really don’t understand why you feel like you need to do this- it’s stupid!
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lewisli_
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(Original post by Sophhhowa)
You’re dad cannot be qualified because if he was he would NOT let you do this. DO NOT CARRY OUT THIS EXPERIMENT UNLESS YOU ARE IN A LAB USING AN APPROVED METHOD AND PROPER EQUIPMENT UNDER THE SUPERVISION OF YOUR TEACHER! I really don’t understand why you feel like you need to do this- it’s stupid!
He’s already made a risk assessment and is doing it in a well vented area and has PPE. Hardly any of the stuff he’s using is at all dangerous as they’re not even lab grade, I really don’t see any issue? He has experience as a chemist and he’s done his research...
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lewisli_
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(Original post by Dr Sarkis)
You're absolutely right, I should find a kettle...
Haha no, it's fine, I've been allergic for the last 5 years and so I can barely smell anything.. It's nothing to do with SARS-CoV-2 but hopefully I can still get this experiment done before a neighbour will have any complaints...
About the time consumption? Yes, I thought about it and if it doesn't work (which it is pretty much guaranteed to not), then I'll just purify my own ghee as and try separate butyric acid from that.
Water has a boiling point of around 100.0 °C whilst butyric acid has a boiling point of about 163.5 °C. So it should be no problem to just boil the water by repeated heating! I'd say there's plenty of kettles that can get there, but anyway most water particles will probably evaporate way before that.
I just need to get the delivery tube done and some icepack.
Thank you ^_^
I think perhaps use a pot and a heat source rather than a kettle because it would be easier and more efficient than repeated heating. With a boiling point difference that large, you’ll probably know when all of the water would have evaporated away.
Good luck and I’d love to know what happens
Last edited by lewisli_; 1 year ago
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username5154386
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(Original post by lewisli_)
I think perhaps use a pot and a heat source rather than a kettle because it would be easier and more efficient than repeated heating. With a boiling point difference that large, you’ll probably know when all off the water would have evaporated away.
Good luck and I’d love to know what happens
Hey, thanks
Yeah, I thought about that. Also, you're right about the boiling point different, that's why I thought it's doable.
I sure will
Even if nothing comes out of this experiment I'll at least be able to say I've learnt a lot
Like, all those words, "miscible", "precipitate", "standard solution" kind of meant nothing to me when we did them at school (or if they did, I hadn't really known what they mean in practice) but now I've actually had time to internalize.
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lewisli_
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I’m not really sure what you mean about the filtering through the cotton and the separating funnel though. Is it just to remove the solid fatty bits and then distillation to purify the butanoic acid?
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username5154386
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(Original post by lewisli_)
I’m not really sure what you mean about the filtering through the cotton and the separating funnel though. Is it just to remove the solid fatty bits and then distillation to purify the butanoic acid?
Yep exactly, because I tried removing the fatty acids directly by pouring carefully but the sodium caseinate and other protein emlusions always flow quickly and end up getting poured too... Anyway I don't think my fermenter is working very well, it was supposed to give me a high yield due to the breaking down of triglycerides of the mashed potatoes I put in there but apparently it didn't...
I will wait those 2 weeks, and if it doesn't work, I'll just use ghee instead
LOL, I just realised if I wrote I just used butyric acid from ghee then the procedure would be like 3x times less complicated. Only that it's a way less creative way of doing it and it also means I'd have to buy like 5 butter cubes in order to get a sufficient yield which sucks...
I just thought about it and I think filtrating and separating followed by distillation should work much better than adding tons of calcium chloride to dry the water. I saw on this science forum online that a guy said it's faster to distill. And that's also considering the fact that I simply do not have calcium chloride. I guess if I needed calcium chloride I could just react some eggshells (calcium carbonate) with tons of dilute hydrochloric acid next time I make an omelette, but to be honest that'd waste wayyy too much acid.
Once again thanks for understanding!!
I'll just PM you when/if this is done. Lol, got a personal statement deadline on the 4th of May and like 3 further maths end-of-unit tests to prepare for. I may as well start revising at full steam otherwise this experiment will be in vain...
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username5154386
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It's weird, I am getting contradicting advice about whether or not to use hydrochloric acid as a catalyst... The thing is, sulfuric acid catalyses the esterification whilst also dehydrating the water molecules produced in the end, which by Le Chatelier's principle means that we end up with a dynamic equilibrium shifting to the right, producing more esters more quickly...
My teacher said that all strong acid catalysts can be used in this reaction, and guys on Quora say that "a catalytic amount of concentrated strong acid" is enough, but then some other people are telling me that actually hydrochloric acid will make the equilibrium shift to the left, producing less yield... Anyway, I'll do what I can, if it doesn't work then too bad. I can't do anything about it. I am not going to attempt to use sulfuric acid because I know it's will be almost impossible to obtain. This sucks, but yeah..
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