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The_Davster
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Glyoxal Synthesis
For Acquisition, contact your favorite photography supplier and ask them to get it for you, it is slowly replacing formaldehyde as it is less toxic,
some suppliers already have it in stock.
[Edited on 5-9-2005 by chemoleo]
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vulture
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Glyoxal synthesis reportedly works through careful oxidation of ethanol with HNO3. That's all I have, maybe somebody can dig up a patent on that
one.
EbC: Context
[Edited on 5-9-2005 by chemoleo]
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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IPN
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Here is what Ullmann says about Glyoxal synthesis:
| Quote: | From Acetaldehyde. Oxidation with nitric acid was examined by LJUBOWIN as early as 1875 and patented in 1942 BF885931. Reaction takes place at ca. 40
°C and is carried out industrially as a continuous process. Maximum yield is ca. 70 %; selectivity is a function of the relative concentrations of
reagents. After the removal of excess acetaldehyde, the glyoxal formed, which is contaminated with acetic, formic, and glyoxylic acids, is purified by
passage of the aqueous solution through an ion-exchange resin. The solution is then concentrated to a glyoxal content of about 40 %.
Selenium oxide is more selective than nitric acid, and the yield is ca. 84 %; the selenium can be recycled by oxidation with hydrogen peroxide
FR2038575. This process has not been carried out on an industrial scale.
From Ethylene Glycol. The gas-phase oxidation of ethylene glycol by atmospheric oxygen in the presence of dehydrogenation catalysts (metallic copper
or silver) represents the basis of the Laporte process GB1272592 and has been used in several industrial production processes. Reaction occurs between
400 and 600 °C; the yield is 70 – 80 %. The main impurity is formaldehyde , whose subsequent separation is difficult. This reaction has also been
carried out in the liquid phase and under irradiation.
Other Processes . Ethylene can be oxidized by aqueous nitric acid in the presence of palladium DE1166173, by atmospheric oxygen, or by selenium oxide
deposited on silica. Glyoxal may also be formed by oxidation of acetylene GB1071902 or benzene US3637860 with ozone. Ethylene oxide has been proposed
as a substrate for oxidation. Although oxalic acid and its derivatives can be reduced to glyoxal, these processes have not been developed further.
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Here is the orgsyn.org's synthesis of glyoxal
[Edited on 2.9.2005 by IPN]
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S.C. Wack
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Vanino details the procedure from aq. acetaldehyde/HNO3, citing 6 articles. No mention of yield, but I would bet that it isn't high.
Gallica's Beilstein 1, 786 cites the earliest of the 6, Ber. 10, 1365 (1877) - but yield in this ref really sucks, this is improved upon in
abstracts of the Russian articles such as Ber. 14, 2685 (1881). Beilstein also abstracts using paraldehyde instead, from Bull. Soc. 41, 242.
Also in German, DE573721.
Interesting choice of thread title.
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The_Davster
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Could there possibly be a electrochemical route to glyoxal? Anyone have the electrical potential for the oxidation of ethylene glycol to glyoxal? Or
the potential for the reduction of oxalic acid to glyoxal?
Yes I know its a long shot...
[Edited on 3-9-2005 by rogue chemist]
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chemoleo
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More on glyoxal synthesis & properties
Yes, in Bayer/Walter it says that the oxidation to glyoxal can be achieved with HNO3 due to the removal of glyoxal as the di-bisulfite addition
product.
Else, with paraldehyde and selenium dioxide (Rabjohn, Selenium Dioxide Oxidation, Org. Reactions 5, p.331 (1949)).
Methylglyoxal can be similarly made with SeO2, but from acetone - which is readily accessible (unlike acetaldehyde/paraldehyde), while the
methylglyoxal is propably almost as useful for many reactions.
Glyoxal is also the most simple organic AND coloured compound (it forms yellow prisms, with green vapours and melts at 15 deg C, and burns with a
violet flame), and is the dihydrate in water. It polymerises easily to colourless polyglyoxal, which can be depolymerised with P2O5 at heat.
PS Rogue, re. electrochemical reduction/oxidation, is there evidence in the literature anywhere, with simple alcohols?
The question is how oxidation onwards to oxalic acid is prevented. I should think that this would be very tricky, as (if the oxidation is a random
process), you will also get CHO-CH2OH, HOOC-CHO and (COOH)2 of course, while CHO-CHO is only one of the possible products.
[Edited on 5-9-2005 by chemoleo]
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The_Davster
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Yes Chemoleo, I really believe it can be done. (I have a bit of an electrochem obsession going currently ). According to "manufacture of chemicals by electrolysis" superimposing AC on DC current allows for the
preparation of compounds not normally easily prepared by electrolysis. "ethyl and propyl alcohols give the corresponding aldehydes whereas when
oxidized by continous current only, the principlal product is the corresponding acid" I imagine this can be done with ethylene glycol as well to
get glyoxal, but unfortunatly no info is given about electrode types . Interesting
to note that superimposing AC on DC also gives more ozone when electrolysing dil. H2SO4, and can be used to make benzaldehyde and benzoic acid from
toluene when with just DC CO2 is produced. I really want to experiment with these methods of electrolysis, and am gathering the parts for a proper
power supply. If anyone can gather any journal entries about these methods of electrolysis please post them here.
Its a great file that pdf...even some stuff on electrolytic diazotizations.
[Edited on 6-9-2005 by rogue chemist]
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Phel
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| Quote: | Originally posted by rogue chemist
Could there possibly be a electrochemical route to glyoxal? |
Perhaps an OTC electrochemical road to glyoxal:
| Quote: |
The electrochemical oxidation of maleic acid on tungsten anodes has been investigated. Glyoxal and carbon dioxide were the main products together with
tartaric acid and acetaldehyde. Glyoxal is also obtained as the main product from the oxidation of d-tartaric acid. Under the same
conditions succinic acid is completely oxidized to carbon dioxide and water. |
Ref:
Journal of Applied Electrochemistry
SSN: 0021-891X (Paper) 1572-8838 (Online)
DOI: 10.1007/BF01112074
Issue: Volume 12, Number 1
Date: January 1982
Pages: 127 - 133
(sorry about the bump )
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The_Davster
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Hmm the last few lines of the article do not bode well, seems there is an annoying oxide layer which builds up on the electrode, hindering further
oxidation of the tartaric.
Eh, I'll get some tartaric acid soon hopefully and give this a shot.
They seem to imply at one point that tungsten is not necessary, and that other electrode materials give impure results. The reference for it is from
"Ann. Acad. Sci. Fenn". What is that without abbreviations so I can look it up?
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Phel
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I believe what you are looking for is "Annales Academiae Scientiarum Fennicae". Looking forward to hear your results!
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stygian
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The Org. Syn. Page says it can also be made by hydrolysis of dichlorodioxane. Would this be the same dichlorodioxane formed from dioxane/TCCA/iodine?
Ethylene glycol + H2SO4 yields dioxane if I recall correctly.
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The_Davster
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That is OTC but it involves way too nasty precursors to make it useful. Frogfot has the dioxane synth you mention on his page.
I have been unable to find the reference I mentioned earlier. The article must have wrote it down wrong. I am still waiting on my tartaric acid,
hopefully I find time to try this once I get it.
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Mason_Grand_ANNdrews
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I guessing a cheap glyoxal synthesis is most attractive.
I have searched sometimes the web, but i can`t found somewhat about the glyoxal hydrate synthesis.
A reported link  is helpful for me.
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acetate
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| Quote: | Originally posted by Phel
Ref:
Journal of Applied Electrochemistry
SSN: 0021-891X (Paper) 1572-8838 (Online)
DOI: 10.1007/BF01112074
Issue: Volume 12, Number 1
Date: January 1982
Pages: 127 - 133
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Attachment: j7n274305v3h0272.pdf (513kB)
This file has been downloaded 2239 times
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scientistfromdarkness
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Why to synthesize when you can buy it from Sigma-Aldrich. It is not expensive
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Eclectic
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Why cook when you can have fast food?
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guy
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Oxidation of ethylene glycol in gas phase with copper oxide (~300oC) yields glyoxal.
Source
| Quote: |
Two well established processes employed for the production of glyoxal are the gas-phase oxidation of ethylene glycol with air in the presence of
copper or silver catalysts at elevated temperature (about 300 °C) and the liquid-phase oxidation of acetaldehyde with nitric acid (Chumbhale &
Awasarkar, 2001). |
[Edited on 2/11/2007 by guy]
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not_important
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The alcohol (or glycol) and air oxidation over copper or silver is a little tricky, as the gas mixture has flammible and explosive ranges for oxygen
content wanted for good conversion - be careful with that.
Just running the alcohol over Cu or Ag will give some aldehyde formation CH2OH => H2 + CHO. Not as good as when oxygen/air is added to removed
hydrogen and for the reaction but often acceptable.
For a batch mode process, copper oxides can be used in place of metallic copper. The alcohol/glycol reduces the oxide, which functions as an oxygen
source less likely to give annoying flashback and explosive pops. The oxide can be regenerated by passing air over the copper while heating it.
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Sauron
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The Org.Syn. prep uses selenous acid and explains why it was preferred to the oxide. Acetaldehyde as paraldehyde is the starting material, and it is
done on a scale that yields c.350 g of the bisulfite addn cpd.
The procedure is attached as a pdf
[Edited on 11-2-2007 by Sauron]
Attachment: CV3P0438.pdf (129kB)
This file has been downloaded 2053 times
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Sauron
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Serendipity Happens
The nice thing about having electic interests in chemistry is that sometimes when you are hunting through the lit. for one thing, something else
completely different but still of great interest jumps off the page at you.
This just happened to me. I was reading a JACS communication that is related to my novichok lit.search and found that the authors had been
misreferenced as those of the immediately following article on same page.
The adjacent article is:
A New Synthesis of Glyoxal Tetramethyl Acetal
Ralph C. Schreyer
JACS 73 pp 2962 - 2963 (1951); DOI: 10.1021/ja01150a535
The DuPont authors describe chlorination in the cold of 1,2-dimethoxyethylene to give the tetramethylacetal of glyoxal in high yield.
MeOCH=CH0Me + Cl2 -> (MeO)2C-C(OMe)2
I have not checked into the availability of the starting material yet, I came straight here to post.
Article is attached below, Enjoy!
[Edited on 12-2-2007 by Sauron]
Attachment: glyoxaltetraMeacetal.pdf (306kB)
This file has been downloaded 1652 times
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Sauron
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Aldrich does not have this starting material, but here is a link to Springer Verlag and a Russian article on this kind of compound (ethers of
1,2-ethenediol)
http://www.springerlink.com/content/j1221718j8514847/
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adi54
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3%0% solution of Acetaldehyde is to be reacted with 61% nitric acid using small pinch of Sod. Nitrite at 40-43deg cel . reactin is instatanious only
thing is you have to add Nitric acid at 40 deg to start reaction then this is exothermic and is to be cooled to maintain temp.
Reaction product is Distilled under vacuum to remove dil acetic acid and concentrate is to pass through Weak Anion resin and reconcentrated under vac
to 40% Sp gr 1.27.
But what you are going to use this in pl do let us know .
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Sauron
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@adi54, please edit your post.
Who are you replying to?
Do you mean 30% acetaldehyde, you wrote 3%0%
This looks like a glyoxal prep but my post immediately above concerned 1,2-ethenediol and the conversion to glyoxal tetramethylacetal.
Please clarify.
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adi54
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Sorry it is 30.0% acetaldehyde and since the thread was for Glyoxal I did not clarify , sorry for the touble
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Sauron
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No problem, it's a useful prep since many will prefer HNO3 to selenium oxide.
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