Sciencemadness Discussion Board

Is there a route to glyoxal from oxalic acid in OTC products?

Hey Buddy - 26-1-2021 at 11:17

Is there any route to glyoxal through oxalic acid? I would like to synthesize glyoxal but the two simplest methods seem to be 1) ozonolysis of benzene/tolune at low temp in pres of zinc. 2) the first production of glyoxal by Dubois used ethyl alcohol treated by HNO3.

Is there a route via oxalic acid or otc acid in hardware stores? I need to make some because I can't afford it anymore and I'm tired of suppliers selling out. I'm scared to try to cook ethylene glycol at high temp + catalyst and keep reading about detonations with ozonolysis.

Any tips or help? Thanks.

B(a)P - 27-1-2021 at 00:28

I thought the same thing, it looks like it should be possible. I did quite a bit of research and couldn't find an option.
It seems that oxalic acid to glyoxalic acid is possible via oxidation with HNO3. Electrolysis is also possible https://patents.google.com/patent/US5395488A/en
I couldn't find a route from either glyoxalic acid or oxalic acid to glyoxal. Everything I found was about glyoxal to gloxalic acid or oxalic acid, surely this is reversible?

I would be very curious to hear from others on this.

macckone - 27-1-2021 at 02:12

The most obvious is a strong reducing agent like lithium aluminum hydride.

Going from oxalic acid to glyoxal should be possible with something like that but not cost effective.

Oxidizing aldehydes to acids is generally easier and cheaper than reducing acids to aldehydes.

njl - 27-1-2021 at 06:06

Electrolysis sounds promising. I would try ethylene glycol oxidation, I don't see why one would be hesitant. I would set up a metal retort with a take-off pipe, fill the pipe loosely with catalyst, heat the retort and take-off in an open flame, and distill for as long as you're comfortable.

Hey Buddy - 27-1-2021 at 07:23

Quote: Originally posted by njl  
Electrolysis sounds promising. I would try ethylene glycol oxidation, I don't see why one would be hesitant. I would set up a metal retort with a take-off pipe, fill the pipe loosely with catalyst, heat the retort and take-off in an open flame, and distill for as long as you're comfortable.


I mis-wrote, sorry: --was wanting to "avoid" glycol, simply due to high heat and use of catalyst. I was "scared" to do ozonolysis since some of what I read is theoretical and deduced from the German patents that describe frequent detonations of products. IMO for ozonolysis, tolune seems the easiest because Tolune is common, or can be fractioned off from "premium gasoline" @~6%. Benzene purportedly gives 3 glyoxal. Tolune gives 2 glyoxal and 1 methylglyoxal, which i assume could then be processed to glyoxal or separated if not.

For catalysts in the retort method, do you think a graphitic carbon nitride catalyst in the retort would work? g-CN is supposed to be effective for oxidation. I have a bunch of urea and could make some.

For electrolysis, I'm unfamiliar with electrolytic production of glyoxal. Could you write some more about that please?
Thanks a lot. This has been a frustration of mine for a year and I've been avoiding it by buying online, but they sold out of stock so now I'm determined to make it in house.

njl - 27-1-2021 at 08:19

Refs from a similar thread:

Electrochemical process: http://www.sciencemadness.org/talk/viewthread.php?tid=4425#p...
From dimethoxyethane: http://www.sciencemadness.org/talk/viewthread.php?tid=4425#p...
Collection of preps: http://www.sciencemadness.org/talk/viewthread.php?tid=4425&a...
Sodium Bismuthate as an oxidant: http://www.sciencemadness.org/talk/viewthread.php?tid=4425&a...

You could also look into any number of selective oxidizing agents for primary alcohols, but they may react differently with glycols. TEMPO + hypochlorite comes to mind.

Hey Buddy - 27-1-2021 at 14:18

Quote: Originally posted by njl  
Refs from a similar thread:

Electrochemical process: http://www.sciencemadness.org/talk/viewthread.php?tid=4425#p...
From dimethoxyethane: http://www.sciencemadness.org/talk/viewthread.php?tid=4425#p...
Collection of preps: http://www.sciencemadness.org/talk/viewthread.php?tid=4425&a...
Sodium Bismuthate as an oxidant: http://www.sciencemadness.org/talk/viewthread.php?tid=4425&a...

You could also look into any number of selective oxidizing agents for primary alcohols, but they may react differently with glycols. TEMPO + hypochlorite comes to mind.


Rad.
When you say TEMPO, do you mean the insecticide?

njl - 27-1-2021 at 15:20

Negatory. Thats Tetramethyl-piperidine n-oxide. It's a catalyst for the oxidation, since it is the active oxidizing agent, it oxidizes the substrate. Then, the original TEMPO is regenerated from the amine by NaOCl.

Tellurium - 24-2-2021 at 18:00

I think the most easy(and possibly also cost effective) preparation should be using TEMPO, as njl said. Maybe TEMPOL could also be used, at least I had great success when making Benzaldehyde from Benzyl alcohol and NaOCl using TEMPOL. TEMPOL has the advantage, that it is usually way cheaper, as it is used in quite big amounts in industry(it's used to control polymerisations). TEMPO can be quite expensive to buy in small amounts, but you could also make it yourself.

clearly_not_atara - 25-2-2021 at 08:45

It seems like the "clean" way would be to nitrosate acetaldehyde to glyoxal monoxime... hard to find a ref for this rxn, though. I assume this is the underlying mechanism of the well-known ethanol+nitric acid method.

EDIT: I'm not far off:
https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.5020221...

" The presence of nitrous acid was necessary for the reaction."

[Edited on 26-2-2021 by clearly_not_atara]

Mateo_swe - 1-3-2021 at 14:10

I read that ozonolysis of Maelic acid makes glyoxalic acid, i include the paper.
This was something i considered trying sometime, but can it explode?
Or was that just with ozonolysis of benzene/tolune and not with ozonolysis of Maelic acid?

Attachment: Production of Glyoxylic acid by ozonolysis of Maleic acid.pdf (240kB)
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