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Melgar
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Quote: Originally posted by theAngryLittleBunny  | | The actual name of the reaction, hmm....as far as I know, I don't think there is a name for the oxidation of sugar by nitric acid, but please correct
me if I'am wrong. And I didn't know that you're 13 years older then me and therefore probably much more experienced. As others said, I rather like to
see the whole procedure, because I generally like to know exactly what to expect before doing it myself. But if you you're more experiwnced, reading a
paper is much more efficient. |
Actually, you at least were considerate enough to describe the reaction, so I really shouldn't be complaining in this thread, but some other one. The
reaction is pretty ancient though (first recorded in 1745):
https://en.wikipedia.org/wiki/Oxalic_acid#History
I don't fault anyone for learning chemistry from Youtube videos, I'm sure they're helpful for seeing exactly how a reaction is done and how it looks
to do it. It just sounds silly to attribute a centuries-old reaction to a Youtuber, at least to me. The only thing that really grates on me is when
I'm trying to answer someone's question, and ask something like "well, what reaction did you use to make it?", and they say "the one NileRed used" or
something, rather than actually describe the reaction.
However, you are hereby commended for actually describing the reaction as "oxidation of sugar by nitric acid" so that I could tell what you were
talking about. My irritation was, in fact, misdirected.
To get the subject back on topic, adding hydrogen peroxide to nitric acid is very helpful for reducing NOx fumes and increasing the useful life of
your acid. Also, benzotrichloride is probably the most OTC-accessible reagent I can think of for preparing acyl chlorides. It'd probably work really
well for oxalyl chloride too, since oxalyl chloride has a boiling point of like 61˚C, and is easily distilled from a mixture of oxalic acid,
benzotrichloride, benzoyl chloride, and benzoic acid.
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JJay
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Whoah, cool, the original reference is in Latin: https://books.google.com/books?id=HcuNbkfxYQMC&pg=PA238#...
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clearly_not_atara
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Yeah, the problem with most chlorinating agents here is that the anhydride of oxalic acid, if produced, decomposes instantly to CO2 + CO, ruining your
procedure. I assume this is why PCl5 is preferred over any related reagent: it forms an intermediate phosphate ester, and one equivalent of PCl5 can
convert oxalate all the way to oxalyl chloride wothout the intermediacy of HO2CCOCl (oxalyl monochloride), which likely decomposes spontaneously to
CO2 + CO + HCl.
SCl4 can chlorinate oxalate fully in one go. Benzotrichloride might work. Phthaloyl chloride, SOCl2, POCl3, TsCl, MeCN*HCl, etc will likely fail and
produce gases.
EDIT:
| Quote: | | Historically oxalic acid was obtained exclusively by using caustics, such as sodium or potassium hydroxide, on sawdust. |
[Edited on 22-5-2017 by clearly_not_atara]
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Alice
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Not directly a contribution to this challenge, as it is reported not to work for oxalic acid is the use of SiCl4 to convert carboxylic acids into the
corresponding acid chlorides: Silicon tetrachloride as a reagent for the preparation of acid chlorides
Maybe TiCl4 then? 
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clearly_not_atara
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I suspect that TiCl4 would react by the same or similar mechanism as SiCl4; particularly, that a second equivalent of TiCl4 must react with the
titanium carboxylate in order to generate the acyl chloride, and this occurs with titanium and silicon particularly because they are not very eager
double-bond formers, so it does not make sense to draw a mechanism involving Si or Ti with a double bond in it. So in order to release the carboxyl
group, the oxygen must have something else to bond to, most likely Ti.
However, in this case the molecular metal carboxylate could react with itself generating oxalyl anhydride (particularly because oxalyl is an ok
leaving group) and thus decomposing.
By contrast here is the mechanism I am proposing for SCl4:
although I am not sure of this. Clearly if SOCl2 is used the cyclic intermediate would decompose to SO2 + CO + CO2, right?
But with benzotrichloride you get benzoyl chloroglyoxylate which is fine. I think.
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Alice
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Regarding TiCl4, I think you are right, didn't think about the double bond issue...
Hypothetically Ti(C2O4)2 may form as well as a the mixed compound TiCl2(C2O4) which might give a TiO2 network - or not. 
Some hints about the action of TiCl4 on acetic acid can be found here: http://pubs.acs.org/doi/abs/10.1021/ja01490a047 or for benzoic acid: http://onlinelibrary.wiley.com/doi/10.1002/prac.19590080108/...
For SCl4 I would have drawn the same mechanism although not sure if SCl2(C2O4) or SCl(C2O4)⁺ x Cl⁻ or there is an equilibrium anyway.
For SOCl2 I imagine either decomposition occurs on the cyclic intermediate or it survives resulting in the mixed anhydride: HSO3-C2O2-Cl which may
further decompose leading to HO-C2O2-Cl and SO2.
| Quote: | | But with benzotrichloride you get benzoyl chloroglyoxylate which is fine. I think. |
Looks good, I wonder if there is a literature procedure for the reaction or similar reactions?
[Edited on 23-5-2017 by Alice]
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JJay
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It's been a while since I posted this, so I figured I would give this thread a bump.
The challenge is most definitely still on. There has been some very interesting and I think fruitful discussion so far. Submissions are due September
1 at midnight in your time zone. Remember, to win the prize you must actually produce some oxalyl chloride. If more than one person successfully
produces oxalyl chloride, the easiest and most accessible synthesis will be chosen as the winner.
The prize will be a new flask like this one: http://www.ebay.com/itm/500ml-Customized-Quartz-Distilling-F...
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chemplayer...
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Interesting challenge! We tried directly chlorinating anhydrous oxalic acid with PCl3 and this didn't work, apparently requiring PCl5 to work. So
phosphorus-based reagents are not necessarily suitable intermediates anyway.
The only thing we found which could (in limited yield) generate an OTC acid chloride was the reaction of the cold acid amide and acetonitrile together
with HCl gas (all under anhydrous conditions of course).
Does oxalylamide (oxalic acid diamide) exist? Could it be produced from oxalic acid and urea? Could this be dissolved in acetonitrile and then dry HCl
gas passed in whilst cold for a duration, and the result then distilled (bp ~60C)...
Of course this then requires to get acetonitrile via OTC sources...
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Cryolite.
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Oxamide does in fact exist. It is made industrially by hydrating cyanogen or dehydrating ammonium oxalate. However, I worry that the mono chlorinated
intermediate may just decompose or dehydrate, to either CO or cyanogen.
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clearly_not_atara
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Oxamide is produced by the pyrolysis of ammonium oxalate. This is not a high yielding reaction:
4(NH4)2O2CCO2 >> 4 NH3 + CO + CO2 + 2NH2COCO2H + NH2COCONH2 + 5 H2O
Oxamic acid, the other component, dissolves in alkaline water and precipitates with addition of Ca2+ or Ba2+. Oxamide is poorly soluble. Small amounts
of hydrogen cyanide are produced.
See "The decomposition of bioxolate of ammonia by heat". In the case where oxamide rather than oxamate is progressively chlorinated I think there is a
significantly better chance of success.
[Edited on 26-6-2017 by clearly_not_atara]
[Edited on 26-6-2017 by clearly_not_atara]
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JJay
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Some research on the subject suggests that it is possible to prepare acetonitrile from alanine and TCCA: http://www.sciencemadness.org/talk/viewthread.php?tid=9094#p... Apparently, sodium hypochlorite has a similar action.
I've read that pH can influence whether an aldehyde or a nitrile forms, with alkaline pH leading to nitrile formation. I've also read results that
contradict these findings. It has been suggested that concentration of the amino acid matters also. I tried forming aldehydes in very dilute solution
this way a while back and never managed to isolate any, but Amos posted NMR results for phenylacetonitrile made with concentrated bleach some months
ago: http://www.sciencemadness.org/talk/viewthread.php?tid=32534
It seems reasonable to suppose that acetonitrile could be made by the action of concentrated bleach on alanine.
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Melgar
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| Quote: Originally posted by JJay | It seems reasonable to suppose that acetonitrile could be made by the action of concentrated bleach on alanine.
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The only annoying part would be sourcing the TEMPO, which is a lot harder to get than acetonitrile.
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
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JJay
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| Quote: Originally posted by Melgar | | Quote: Originally posted by JJay | It seems reasonable to suppose that acetonitrile could be made by the action of concentrated bleach on alanine.
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The only annoying part would be sourcing the TEMPO, which is a lot harder to get than acetonitrile. |
They used TEMPO in the first paper on that thread but not in the others. Also, it was used for an experiment involving benzylamine in DCM to elucidate
the mechanism of the reaction; the procedures at the end of the document performed in aqueous base on amino acids do not require TEMPO, nor do the
(admittedly lower-yielding) procedures in the half dozen other papers on the subject.
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clearly_not_atara
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The only acetonitrile synth anyone needs is refluxing acetamide over Al2O3 that was washed with phosphoric acid. Acetonitrile distills out (bp 82 C)
and can be collected in a condenser.
http://www.sciencemadness.org/talk/viewthread.php?tid=11137&...
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JJay
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I wonder if garden-grade pumice would work instead of alumina. The trick is cooling your reflux column with boiling water.
Maybe you could use a coffee percolator?
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JJay
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Here's a good example of oxalyl chloride in amateur use: Making Glow Sticks
And here's another: Vapor Activated Glow Stick
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karlos³
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The Anthony-Speeter synthesis of indole glyoxylic amides is another quite interesting application of oxalyl chloride, very easy to do for the amateur
and a rewarding experience as well.
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Rhodanide
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Good luck even obtaining TiCl4, I sure tried... and failed. If you find any, it's probably somewhere where it can't *legally* be removed.
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clearly_not_atara
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I was thinking about other esters that could be converted to the chloride -- maybe try radical chlorination of dibenzyl oxalate? If I had to guess,
I'd say that 1,6-diphenyl-1,1,6,6-tetrachloro-2,5-dioxa-3,4-dioxohexane should decompose to oxalyl chloride and benzoyl chloride, as long as the
intermediate products don't decompose first.
Maybe ethylene oxalate could be perchlorinated somehow... pyrolysis might give two equivalents of oxalyl chloride if you're lucky.
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JJay
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I'm surprised no one has suggested antimony pentachloride.
Edit: I just found this thread, where Nicoderm stated that won't work: http://www.sciencemadness.org/talk/viewthread.php?tid=11989
[Edited on 11-7-2017 by JJay]
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fumingjohnny
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alternate synthesis
1. Thionyl chloride can be easily prepared by the action of dichlorine monoxide on elemental sulphur at -12 degree celcius(salt-ice bath can cool down
to -20). The thionyl chloride formed is excellent in converting oxalic acid to oxalyl chlorides. Dichlorine monoxide can be made by passing chlorine
over mercuric oxide or sodium carbonate.
2. You may want to try treating silicon with chlorine to form silicon tetrachloride and then reacting oxalic acid with SiCl4 to form SiO2 and HCl and
Oxalyl chloride.
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fumingjohnny
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3.
3. chlorination of diethyl oxalate.....(CH3CHCl)2(COO)2 and subsequent heating will disproportionate it into acetaldehyde and oxalyl chloride. The
oxalyl chloride is immediately distilled off using a water bath.
4. Reaction of Triphenylphosphine with Carbon tetrachloride and oxalic acid should yield oxalyl chloride, triphenylphosphine oxide and chloroform.
(please try it and let me know the results)
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fumingjohnny
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5. Sulfuryl chloride SO2Cl2 is used for chlorinating calcium salts of carboxylic acids to form acid chlorides and calcium sulphate. If anyone here has
access to sulfuryl chloride then try reacting it with calcium oxalate. The products should be calcium sulphate and oxalyl chloride.
P.S: please post the results.
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woelen
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@fumingjohnny: It is best to put everything in a single post. These three posts can be left as they are now, but if you post again, we would like to
have everything combined in a single post.
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JJay
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| Quote: Originally posted by fumingjohnny | 1. Thionyl chloride can be easily prepared by the action of dichlorine monoxide on elemental sulphur at -12 degree celcius(salt-ice bath can cool down
to -20). The thionyl chloride formed is excellent in converting oxalic acid to oxalyl chlorides. Dichlorine monoxide can be made by passing chlorine
over mercuric oxide or sodium carbonate.
2. You may want to try treating silicon with chlorine to form silicon tetrachloride and then reacting oxalic acid with SiCl4 to form SiO2 and HCl and
Oxalyl chloride. |
I don't know how easy that is in practice.... It is theoretically possible to make thionyl chloride by cracking sodium bisulfate to prepare oleum and
reacting the oleum with sulfur dichloride, but this requires high temperatures and is quite toxic and extremely smelly. The purification method
suggested in Small Scale Synthesis of Laboratory Chemicals is to distill the thionyl chloride from quinoline and linseed oil. This is all conceivably
OTC (except for the quinoline, but you might find a substitute or manage to get through intermediate steps with an impure product and purify later),
but thionyl chloride can't be used to chlorinate oxalic acid directly... which doesn't necessarily mean that there's no way to do it.
It is said that silicon tetrachloride can't be used for a direct chlorination either, but again, that doesn't mean it's impossible to use it in some
sort of chlorination. It's theoretically available OTC.
I'm very curious about benzotrichloride. Free radical chlorination of toluene is about as OTC as it gets.
[Edited on 12-7-2017 by JJay]
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