TheNerdyFarmer
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Formaldehyde from Acetaldehyde and Formic Acid
I am fairly new to organic chemistry so if this is a stupid idea feel free to let me know. As a home chemist starting a lab I have been looking for
OTC chemicals to stock it. But, I can't find formaldehyde seeing as it is kind of restricted. So I tried to come up with an idea on how to make some.
I was wandering if you used acetaldehyde and formic acid if it would yield formaldehyde and Acetic acid as a byproduct.
Here is my chemical equation:
CH3CHO+HCOOH-> H2CO+CH3COOH
It seems like it would work but I've heard that organic chemistry is a bit tricky. If this would not work it would be much appreciated if you all
could give constructive criticism and maybe a better way to do it. Thanks a bunch!
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Metacelsus
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I don't think it would work (I can't think of any plausible mechanism). You might get some lactic acid produced. Alternatively, you could end up
making carbon dioxide and ethanol. In either case, you'd have to use high temperatures and pressures (see: https://pubs.acs.org/doi/abs/10.1021/jp710688u)
In any case, acetaldehyde is usually harder to get than formaldehyde (which you can buy as paraformaldehyde).
Edit: Added reference
[Edited on 10-1-2016 by Metacelsus]
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Crowfjord
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I see your reasoning there, but I think if a reaction proceeded between acetaldehyde and formic acid, the opposite would happen. That is, the formic
acid would act as reductant rather than oxidant. Formic acid, usually along with a catalyst of some sort tends to react along the lines of HCOOH
--> CO2 + H+ + e-. Mainly because carbon dioxide is very thermodynamically stable, and carboxylic acids are pretty
difficult to reduce.
Although formaldehyde solution has become difficult to find these days, paraformaldehyde remains fairly well available. Paraformaldehyde easily
dissolves in refluxing methanol or refluxing water with a few drops of 25% sodium hydroxide. I've made formaldehyde this way, it only takes about 2-4
hours.
Edit: it seems Metacelsus made a similar response as I was typing
[Edited on 1-10-2016 by Crowfjord]
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Cryolite.
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Quote: Originally posted by Crowfjord  |
Although formaldehyde solution has become difficult to find these days, paraformaldehyde remains fairly well available. Paraformaldehyde easily
dissolves in refluxing methanol or refluxing water with a few drops of 25% sodium hydroxide. I've made formaldehyde this way, it only takes about 2-4
hours.
[Edited on 1-10-2016 by Crowfjord] |
Sorry for the off-topic, but where do you get paraformaldehyde locally? I have looked for it in the past, but the only source I could find was
incredibly overpriced mildew odor removers.
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Crowfjord
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I haven't seen anything of decent quality OTC in stores, though it might exist. I get mine from Photographers Formulary. Pure paraformaldehyde might
be available via ebay, as well. Another formaldehyde source to keep an eye out for also would be trioxane (solid camp fuel).
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Magpie
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The OP says he wants formaldehyde. Assuming he means an aqueous solution, ie, formalin, this is readily available over the internet, including
Amazon.
Gaseous formaldehyde is another matter and is a bit tricky to get in pure form.
The single most important condition for a successful synthesis is good mixing - Nicodem
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