Sciencemadness Discussion Board

Formaldehyde synthesis

mauricethegangsteroflove - 27-3-2026 at 17:32

I would like to try synthesizing some formaldehyde so I can try synthesizing some Bakelite and maybe hexamine. A brief search of this forum found that potassium peroxymonosulfate, sold as non-chlorine pool shock, is known to oxidize methanol to formaldehyde.

I've got about 100ml of methanol in a flask with a few grams of potassium peroxymonosulfate and intend to try gently heating it and bubbling the gas that comes off through some water. I'm picturing running a rubber tube down into the bottom of a volumetric cylinder with some cotton in the end to break up the bubbles, maybe with a funnel as a suckback trap.

Has anyone tried anything like this? I haven't seen anything regarding this method, and would appreciate any advice, comments, or "dear God don't do that you idiot" warnings you might have.

Also curious what is happening at the chemical level, if anyone has studied the reaction much, so I can try doing some stoichiometry to optimize this.

Alkoholvergiftung - 27-3-2026 at 22:54

Hexamin could alternativly made with Dichlormethan and alcoholic ammoniasolution in an autoclaven. Temperature over 90C and under 120C. The problem here is the Hardware but you can buy Dichlormethan as an solvent.

mauricethegangsteroflove - 28-3-2026 at 07:46

I don't have an autoclave but that does sound interesting. I will try it if and when I have the means to do so.

I have been speculating about a few ways to do the process I'm attempting, and I think it might work better to just let the KHSO5/Methanol solution sit for a few days, then crash out the paraformaldehyde in some water. I can drop that in some distilled water and just heat and stir it, maybe with a bit of NaOH, and make formaldehyde that way. I think this is probably the best method, and I'm going to try that.

A possible but probably bad alternative (which I will not be trying) to go straight to hexamine might be to just pour some ammonia solution into the flask where the formaldehyde is forming and to boil that off, but I think there will be excess KHS05 in there and I really don't like the idea of boiling down a mix of hexamine and a strong oxidizer like that.

Alkoholvergiftung - 28-3-2026 at 09:48

The only lab methode for Formaldehyd i ve read was oxydation of methanol with mno2 and H2SO4 it forms methylal with an boiling point around 45C that methylal was than heated with 2 parts concentrated sulfuric acid to form formaldehyd. Why this two steps i dont know.
Alternative for methanol to formaldehyd is the catalityc way. Intersting is the Tollens, Trillat , Cambier and Brochet Lamps every one of them made indipendent an desinfection lamp, like and ethanol lamp the wick transports the methnol to an platin wirenet and there it got oxydizes to formaldehyd ive read they could make 5kg formaldehyd per day. Yield was crapy only 25% but if someone use silver instead it might be higher. And if someone can find drawings of this lamps.
Methylal = C3H3O2 Methylendimethylether. bp. 42C was used for anesthesia

[Edited on 28-3-2026 by Alkoholvergiftung]

0_Q - 28-3-2026 at 11:09

look at the data, catalyst K seems to be most yielding and most selective.

they use around 500°C and the catalyst is fairly easy to make.

but they state in the claims they make this in the absence of oxygen.. so heh

Attachment: formaldehyde from meoh via ZnO cat.pdf (569kB)
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[Edited on 28-3-2026 by 0_Q]



also, wouldnt a reflux with active MnO2 do the trick ? - to some extent

[Edited on 28-3-2026 by 0_Q]



also i would look into photocatalystic methods to avoid mean reaction conditions

[Edited on 28-3-2026 by 0_Q]

leau - 28-3-2026 at 20:44

More articles on formaldehyde are in the attached archive :cool:

Attachment: FormaldehydeDocs.zip (6.4MB)
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