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Author: Subject: HOOC-COOH + SOCl2 -> ClOC-COCl ?
Per
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[*] posted on 22-7-2007 at 05:21
HOOC-COOH + SOCl2 -> ClOC-COCl ?


I think it doesn´t work but I ask anyway.

Is it possible to prepare Oxalyl chloride with Thionyl chloride and Oxalic acid in excess?

Heared that it doesn´t work because half-chlorides but I don´t know anything about half-chlorides.

If it works, then as follows:

HOOC-COOH + SOCl2 -> HOOC-COCl + SO2 + HCl

HOOC-COCl + SOCl2 -> ClOC-COCl + SO2 + HCl

Does that work?
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[*] posted on 22-7-2007 at 05:44


Nope.

The only two reagents that do work are PCCl5 and TCT (seperately, of course.)

I would say there is a distant possibility that benzoyl chloride or phthaloyl chloride might chlorinate oxalic acid (preferably anhydrous) and so I think those are worth a try.

TCT chlorinates all the dicarboxylic acids except malonic. For oxalic acid the yield is 52% after 3-4 hours stirring at RT in a i:1:1 molar ratio of oxalic acid:TCT:TEA dissolved in just enough dry acetone to give a clear soln.
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[*] posted on 23-7-2007 at 04:51


Ok, thanks.

Is then at least the theory about the half-chlorides right?


With the Oxalic chloride I wanted to synthesice DNPO, is there any hope of success by just using Oxalic acid and the alcohol 2,4-Dinitrophenol?
The yields mustn´t be high, may the water could removed by aceotrope distillation with CHCl3 (provided that it could be used as solvent) I think, but just if it works.
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[*] posted on 23-7-2007 at 07:18


See the old Roger Adams articles in JACS c.1915-1920 (use the ACS pubs search engine.) He originally got involved with oxalyl chloride by using it as a reagent to derivitize phenols, so I bet the anser to your probelm is in one or another of his articles there.

Along the same lines is hexanitro-oxanilide. From trinitroaniline. See Davis' book, chapter on utilization of coal tar.
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[*] posted on 23-7-2007 at 09:46


Quote:
Originally posted by Per
I think it doesn´t work but I ask anyway.

Is it possible to prepare Oxalyl chloride with Thionyl chloride and Oxalic acid in excess?

I can't believe one can have such short memory! You have already been answered this same question in the thread you yourself started: https://sciencemadness.org/talk/viewthread.php?tid=8742
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[*] posted on 23-7-2007 at 11:56


Couldn´t agree, in this thread was just discussed if the method with the Ac2O works and then PCl3, later TCT, couldn´t find there any information if SOCl2 works.


Roger Adams, hmm, could just find "Organic Reaktions Volume" 1-3, search engine, just don´t know what the ACS pubs search engine is, I know just the search of the board and this doesn´t help me.

Davis´ book, do you mean "Hans Eduard Fierz-David and Louis Blangey" or "David Shirley", and yes, searching is not my force, up to now.
Hexanitro-oxanilide seems to be interesting, all I found about it until now is that it´s an exotic oxplosive and hard to get.


And there´s just one more little idea about the prep. of DNPO:

Would Sodium oxalate and 1-Chloro-2,4-Dinitrophenol work, should produce NaCl and DNPO but seems to be too easy to work.
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[*] posted on 23-7-2007 at 12:28


Phenyl esters can not be prepared from the phenol and the acid, you can see that in the aspirin synthesis. Only anhydrides or acyl chlorides work, and since oxalic acid does not have an anhydride, only oxalyl chloride can work.

Put your energy towards making PCl5 and anhydrous oxalic acid instead of following routes to nowhere.
A preparation of anhydrous oxalic acid is found here:
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...
The CCl4 can probably be replaced by chloroform, cyclohexane or another solvent with similar azeotrope properties as CCl4.

And PCl5 is made via my method with red P in chloroform. Dont forget to remove the residual chloroform completely in vacuum at 100°C, otherwise it will be impossible to separate from the oxalyl chloride.




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[*] posted on 23-7-2007 at 16:04


@Per, By "Davis book" I mean The Chemistry of Powder & Explosives" by T.L.Davis, an oldie but goodie, available free from forum library.

The ACS search engine can be found at the website of JACS. I will look up the particular artticle (I probably have it) and post it here.
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[*] posted on 24-7-2007 at 02:07


Quote:
Originally posted by Per
Couldn´t agree, in this thread was just discussed if the method with the Ac2O works and then PCl3, later TCT, couldn´t find there any information if SOCl2 works.

There can only be two simple reasons for your inability to find the answer in that thread. You either have not read it again or you simply do not know that SOCl2 is called thionyl chloride. In short, you are either too lazy or too ignorant. Both these personal characteristics are to be avoided if you want to work with thionyl chloride, oxalyl chloride and similar nasty stuff that can leave you seriously injured.
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[*] posted on 24-7-2007 at 17:01


@Per

Roger Adams, JACS 37 2716 (1915)

describes phenyl esters of oxalic acid prepared by use of oxalyl chloride in presence of pyridine and at low temperature.

Yields described as quantitative.

He gives an example of di-o-nitrophenyl oxalate, which could not be prepared by previous methods.

Adams' method is to chill pyridine to o C, add the oxalyl chloride slowly w/stirring, then using a spatula, carefully break up the yellow lumps of adduct formed. Two equivalents of the phenol are then added and the mixture kept at 0 C for two hours. It is then poured into ice and conc hydrochloric acid. The pyridine dissolves while the pehnyl ester ppts out.


[Edited on 25-7-2007 by Sauron]

Attachment: ja02177a017.pdf (333kB)
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[*] posted on 25-7-2007 at 10:59


For prep. OXALIC ACID (ANHYDROUS) I would of course use the method with the laboratory oven, had tried it former with 150°C and it works.
A heat magnetic stirrer is at least enough to do this properly.

Quote:
The ACS search engine can be found at the website of JACS. I will look up the particular artticle (I probably have it) and post it here.

That would be great, thanks.


The chemistry of power and explosives:

The nitroanilines are more difficult to nitrate than
aniline because of their inhibiting nitro group, and more easy to
nitrate than nitrobenzene because of their promoting amino group.
In o- and p-nitroaniline the amino and nitro groups agree in
activating the same positions, and both substances yield 2,4,6-
trinitroaniline when they arc nitrated. In m-nitroaniline, the
nitro group "activates" the 5-position, while the amino group
activates the 2-, 4-, and 6-positions. Nitration takes place under
the influence of the ortho-para -orienting amino group, and 2,3,4,6-
tetranitroaniline results.

Trinitroaniline (picramide)
2,4,6-Trinitroaniline, orange-red crystals from alcohol, m.p.
186°, has but little interest as an explosive for the reason that
other more powerful and more valuable explosives may be prepared
from the same raw materials. It may be prepared by nitrating
aniline in glacial acetic acid solution or by the use of mixed
nitric-sulfuric acid in which no large excess of sulfuric acid is
present. The presence of nitrous acid must be avoided, as this
attacks the amino group, replaces it by hydroxyl, and results in
the formation of picric acid. The nitration of aniline in the presence
of a large amount of concentrated sulfuric acid yields
m-nitroaniline73 and later the nitro compounds which are derived
from it.


Have you references about hexanitro-oxanilide,
is the chemoluminescence with this ester better than with DNPO?

And thanks for the attachment, good to have such an instruction.
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[*] posted on 25-7-2007 at 21:09


Acros sells anhydrous oxalic acid, btw.
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[*] posted on 25-7-2007 at 22:18


Ought to be cheaper and less hassle to get from a photography supplier. I think there's a link in the "Readily Available Chemicals" thread in Reagents and Apparatus Acquisition. HTH



Neither flask nor beaker.


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[*] posted on 26-7-2007 at 04:22


Hi

Garage chemist, please direct me your method of making PCl5 with red phosphor and chloroform. I searched this forum but found nothing.

Thank you
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[*] posted on 26-7-2007 at 06:26


Chloroform is only a medium, for elemental chlorination of suspended red P with lots and lots of Cl2.

2 P + 5 Cl2 = 2 PCl5

As you can see the CHCl3 is not involved in the reaction.

If you work out the stoichiometry you will see that need rather a lot of chlorine. DRY chlorine.
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[*] posted on 26-7-2007 at 08:32


Here´s the instruction, unfortunately in german:

http://www.versuchschemie.de/ptopic,124916.html#124916


Getting Oxalic acid dihydrate isn´t a problem, could be as mentioned easily obtained from a beekeeper which uses it to prevent his bees from pest.

[Bearbeitet am 26-7-2007 von Per]
There was a problem with the link.

[Bearbeitet am 26-7-2007 von Per]
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[*] posted on 3-10-2007 at 06:49


It took some time but now
I have phosphorous pentachloride and anhydrous oxalic acid.

PCl5 was prepared from red phosphorous and dry chlorine without a solvent, just leading the chlorine over the phosphorous, of course very slow. It resublimed at the wall of the Erlenmeyer flask and could be easily scraped off.

But now I´m not sure what´s the best way for preparing oxalic chloride by this chlorinating agent.
Chloroform would be resistant but couldn’t used as solvent because of its similar boiling point.
So the question is if just simple mixing PCl5 and anhydrous oxalic acid is the best way for preparing oxalic chloride, they are both volatile and the products are liquids, Cl-CO-CO-Cl and POCl3.
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[*] posted on 3-10-2007 at 06:56


Just mix the reactants dry in the proper proportion and immediately transfer to your distillation setup. When I did this 30 years ago, I tried mixing in a blender, which turned out not to be a good idea because the heat of mixing started the reaction going a bit before I was ready for it.:o

[Edited on 10-3-2007 by Eclectic]
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[*] posted on 3-10-2007 at 06:59


This reaction is done neat, in absence of solvent.

Here's Sartori:

Much better than the garbled version on rhodium.

Note that it takes 400 g PCl5 to chlorinate <100 g oxalic acid and the yield is 50%. This is not efficient, and that is why I like TCT. However, one uses what one can get.

Further note that POCl3 is by product, don't toss that away!

And protect yourself from both products!

[Edited on 3-10-2007 by Sauron]

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[*] posted on 3-10-2007 at 07:15


Actually, HCl gas is evolved, not chlorine, at least I didn't see any when I did the prep., which I found by following the references in the Merck Index. (way before Rhodium's site)
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[*] posted on 3-10-2007 at 07:45


(COOH)2 + PCl5 -> (COCl)2 + POCl3 + H20

Neither HCl nor CO2 is evolved in that reaction. But that water will destroy part of the oxalyl chloride and that will form HCl, CO and CO2. Or it might react with the excess of PCl5 producing HCl and more POCl3. Or it might hydrolyze part of the POCl3. Also giving rise to HCl (and H3PO4 or partially chlorinates derivatives.)

(COCl)2 + H20 -> 2HCl + CO + CO2

PCl5 + H2O -> 2HCl + POCl3

POCl3 + 3 H20 -> H3PO4 + 3 HCl

which may account for the 50% yield if the oxalyl chloride reacts with water formed. But if so then there ought to be PCl5 remaining at end, dissolved in POCl3. Per, see what remains if you distill off the POCl3 fraction (bp 107). Maybe you won't have used up all that nice PCl5.
.

oxalic acid MW 90 (anhydrous)
PCl5 MW 208

So the procedure calls for a 2 to 1 excess of the PCl2. And still a 50% yiels.

But just by looking at it, there ought to be more than 300 g POCl3 and a little more than 125 g in theory of oxalyl chloride so maybe 60-65 g is the realistic guestimate.

To be fair, TCT also gives a 52% yield.

At least this methos is a really good POCl3 prep.

Need I mention that this mixture of two solids needs to be completely ptotected from moisture for the 2-3 days Staudinger (whom Sartori is reciting from) teaches is needed for this reaction?



[Edited on 4-10-2007 by Sauron]




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[*] posted on 3-10-2007 at 08:41


"Neither HCl nor CO2 is evolved. But that water will destroy part of the oxalyl chloride and that will form HCl, CO and CO2."

WTF!? :o You mean it's not, but it is?

Anyway, have a way to get rid of the HCl which, like Schrodenger's cat, must be in a state of quantum indeterminacy. :P

I have, in fact, done this reaction myself on exactly this scale. :cool:

[Edited on 10-3-2007 by Eclectic]
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[*] posted on 3-10-2007 at 19:55


Clearly, what I said was that the reaction of PCl5 and oxalic acid (anhydrous) does not generate any gaseous product.

But I have edited it for clarification.

But the water formed in the reaction reacts either with the oxalyl chloride or with the POCl3 formed or with PCl5 (which is present in excess perhaps for this very purpose.) I can't predict which of those three will occur but whichever, it will produce HCl.

Since the final product is entirely liquid, presumably the PCl5 has all reacted or is in solution in the POCl3 (which certainly dissolves it.)

Ecletic I bow to your superior experience, I never made (COCl2) this way as I was put off by the cost, the low yield and the long rxn time. How much purified product did you get?

POCl3 boils at 107 C. The instruction is to fractionate and collect everything from 60 to 100 C. Then refractionate several times. Oxalyl chloride boils IIRC 62-64 C. So any decent column will cleanly seperate the two, given a >40 C delta in bp. A reasonable reflux ratio is implicit but the fractionation ned not be a heroic one. I'd doubt that more than two distillations are needed. A fast strip and a slow fractionation.

After the strip I'd take off the POCl3, of which there is beaucoup, and see if there's any PCl5 left in the pot.

Assuming that Per started with 100 g red P he ought to have obtained >600 g PCl5, enough to convert maybe 135 g oxalic acid to c.100 g oxalyl chloride, with more than 600 g POCl3 for lagniappe (as we used to say in Nawlins.)

I just ordered 2 Kg oxalyl chloride (about 600 ml per kg). Frigging stuff is $500 a Kg delivered.

I will at some point be trying the following preps of same:

1. TCT in acetone w/TEA
2. Phthaloyl chloride 2-3 mols neat
3. Benzorl chloride (3-4 moles) neat

All with anhydrous oxalic acid.

Another one that just popped up is diethyl oxalate with 2 mols of phthaloyl chloride and chlorosulfonic acid.

The first is in the lit. 52% yield, 3-4 hrs stirring at RT

The rest are in the lit for RCOOH to RCOCl and in a few cases for dicarboxylic acid. But no examples of oxalyl chloride.

However as they are all a lot more convenient than PCl5 (given that red P is a problem for me) they are well worth a try.

[Edited on 4-10-2007 by Sauron]




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[*] posted on 4-10-2007 at 05:35


I think I got about 56 grams oxalyl chloride, with the balance almost pure POCl3. It was a long time ago, but I seem to remember capturing HCl with a scrubber.

I thought PCl5 + ROOH ->ROCl + POCl3 + HCl via abstraction of oxygen and intramolecular rearrangement.

Not sure of the mechanism, but I doubt free H2O ever exists in the reaction.

Aldrich has PCl5 by the kilo really cheap in their catalog.



[Edited on 10-4-2007 by Eclectic]
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[*] posted on 4-10-2007 at 06:47


It's unimportable here. Defense Ministry regs.

And I'm going by the equation in Sartori, see the attachment above. Your equation makes perfectly good sense for a monobasic acid though.

I suppose we could go to the original article in Ber., and see what Staudinger says.

I'm not sure it really matters.

Bottom line is, 400 g of PCl5 gets you <60 g oxalyl chloride, for a lot of work. You have to really WANT the stuff to go this way.




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