Sauron
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Reaction of CC (TCT) w/Carboxylic Acids in Presence of tert Amine
This is a reaction that I have long proposed here as a general preparative method for acyl chlorides of both mono- and dicarboxylic acids of general
interest, principally acetyl chloride, propionyl chloride and oxalyl chloride.
Recently another member conducted some experiments with this technique in preparation of propionyl chloride. He found the reaction rapid and
exothermic, resulting in a voluminous white precipitate of partially spent cyanuric chloride (with 2 of the three chlorines replaced by hydroxyls.
This is the expected byproduct when the reaction is conducted according to the stoichiometry
2 mols monocarboxylic acid
2 mols tertiary amine (TEA, Et3N suggested by authors)
1 mol TCT
in minimum amount of acetone to give a clear solution, with stirring at 20-30 C for 3 hours, or until no more precipitate forms.
It is clear from the mechanism described and illustrated in the original paper, which is unfortunately missing from the Erowid archive of the Rhodium
archive, where I first saw this article many years ago, that the tertiary amine is continuously regenerated in this reaction.
The authors were unfortunately vague about workup. It seems to me that workup would be facilitated and better economy achieved if the amount of
tertiary amine is reduced from stoichiometric parity to a small mol% of the carboxylic acid, say 5 or 10%.
It is also very likely that in order to make fractionation practical, in the case of liquid products, that solvents other than acetone might be
sought. Acetone is rather close in bp to oxalyl chloride and acetyl chloride.
The stopping of the reaction at the second chlorine is for convenience of operating at ambient temperature. The pKa of the third chlorine of TCT is
very different and would require heating. But in some instances this might be desirable, and in such cases acetone would not be best choice for
solvent. Or else, the reaction could be conducted under autogenous pressure in an autoclave. Most people would elect the former method, for lack of a
pressure reactor.
[Edited on 12-2-2008 by Sauron]
Attachment: CC.pdf (223kB)
This file has been downloaded 499 times
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PHILOU Zrealone
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I wonder if the transchloridation can happen without the help of the amine....maybe under harsher conditions with CTC?
Transesterification is knwon with esters, transamination with amides, transanhydridation with anhydrides...
PH Z (PHILOU Zrealone)
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Sauron
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Tertiary amines are cheap and easy to obtain. Triethylamine, pyridine, diethylaniline are all commonly used for similar purposes.
TCT will chlorinate carboxylic acids without without a tertiary amine but slowly and at higher temperatures.
Compare also the chlorination of alcohols with TCT alone and with DMF to form the DMF-TCT adduct. With variations this reaction can be used to prepare
alkyl bromides and alkyl iodides.
How would you propose to use CTC and what advantage(s) would it offer?
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PHILOU Zrealone
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By CTC I meant cyanuric trichloride = CC
In the article you posted I think they used CC for the trichloro (CTC), the dichloro(CDC) en the monochloroderivative (CMC)...
Quoted:
"In the method now described the reaction is carried out at room T° and CC separates as an unsoluble product;..."
This seems paradoxal as they list CC to be in the reactant...maybe a typo.
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You wrote TCT what is trichlorotriazine what is precisely the same as cyanuric trichloride
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Maybe Isocyanuric trichloride can be used as effectively, it is at least easier to get OTC than CTC.
(-CO-NCl-)3
You are right, they explain that TEA has a catalytic effect so it must be possible to perform the reaction with less TEA but
I found also strange that no monochloaceton of polychloroaceton is formed and come to interfere in the proces...by a second thought maybe it is why
they use as much carboxyacid as TEA...so media is not acidic and not basic enough to allow the annoying side reaction.
[Edited on 12-2-2008 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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PHILOU Zrealone
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[Edited on 12-2-2008 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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chemrox
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| Quote: | Originally posted by PHILOU Zrealone
I wonder if the transchloridation can happen without the help of the amine....maybe under harsher conditions with CTC?
Transesterification is knwon with esters, transamination with amides, transanhydridation with anhydrides... |
I tried that-it doesn't work. Sauron and I corresponded while I attempted the reaction without the amine. In fact what happens is the CTC/acetone
and acid are combined. The reactions starts and proceeds vigorously with addition of the tert amine.
optimization would be using a higher boiling solvent than acetone and TBA instead of TEA. Workup is still a problem because the partially
dechlrinated CTC starts dropping out on removal of the solvent. Hence higher boiling solvents would be desireable so on could distill the acid
chloride from the reaction mixture. I'm going to experiment with solvents and TBA and will post a report.
I still suspect than benzoyl Cl is going to more economical.
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Nicodem
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Stop this acronym madness already! 
Why do some people find it so hard to write "cyanuric chloride", "trichloroisocyanuric acid", etc.? Use copy/paste techniques if you are too lazy!
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Sauron
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There are two standard acronyms for the compound in question. CC cyanuric chlorice as used in the 1979 Tet Lett article and TCT trichloro-s-triazine
as is more common in present day chemical literature. I have NEVER seen this substance referred to as CTC ANYWHERE. CTC usually stands for charge
transfer complex, which is what I supposed you were proposing to (somehow) employ in this reaction, though the logic was opaque to me.
If this is the acronym madness that Nicodem was referring to then I agree with him entirely.
The similarity of TCT and TCCA acronyms has caused a number of confusing mistakes over the years, and is bad enough.
"CTC" should NEVER be used to refer to trichloro-s-triazine.
Whenever possible a drawing of the structure ought to be included so as to make it crystal clear exactly which compound is being described.
Trichloro-s-triazine or cyanuric chloride is the acyl chloride of cyanuric acid, which is cyclic and the chlorines are all on carbon, replacing
hydroxyls.
In trichloroisocyanuric acid, TCCA, the compound is a chloramine. The chlorines are on nitrogen.
Very different chemistries result.
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PHILOU Zrealone
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| Quote: | Originally posted by Sauron
There are two standard acronyms for the compound in question. CC cyanuric chlorice as used in the 1979 Tet Lett article and TCT trichloro-s-triazine
as is more common in present day chemical literature. I have NEVER seen this substance referred to as CTC ANYWHERE. CTC usually stands for charge
transfer complex, which is what I supposed you were proposing to (somehow) employ in this reaction, though the logic was opaque to me.
If this is the acronym madness that Nicodem was referring to then I agree with him entirely.
The similarity of TCT and TCCA acronyms has caused a number of confusing mistakes over the years, and is bad enough.
"CTC" should NEVER be used to refer to trichloro-s-triazine.
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OK I stand corrected but this doesn't change the fact that even the writer of the article confuses cyanuric monochloride, dichloride and trichloride.
It is a pitty acronymisation was made against all logic…CTC, CDC and CMC should have been more obvious than TCC or CC.
I’m also sad about TCAP (tricycloacetonperoxyde) … what should be CTAP (cyclotriacetonperoxyde)…there is only one ring and not three
| Quote: | Originally posted by Sauron
Whenever possible a drawing of the structure ought to be included so as to make it crystal clear exactly which compound is being described.
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That was the reason afterwards I wrote isocyanuric trichloride (ICTC) structure 
(-CO-NCl-)3
| Quote: | Originally posted by Sauron
Trichloro-s-triazine or cyanuric chloride is the acyl chloride of cyanuric acid, which is cyclic and the chlorines are all on carbon, replacing
hydroxyls.
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Don’t tell me, I know, I’m interested in those compounds about a decade ago now…I have very large books on the subject and s-triazine is the
confusing name because under that name were put isocyanuric, cyanuric and trimethylenetriazine (in fact triazanes) compounds.
So 1.3.5 trichloro, 1.3.5 triazacylohexane (NNN trichloro-sym-triazine) and RDX are triazine despites the fact they are saturated and unaromatic…
| Quote: | Originally posted by Sauron
In trichloroisocyanuric acid, TCCA, the compound is a chloramine. The chlorines are on nitrogen.
Very different chemistries result.
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Actually isocyanuric trichloride is a chloramide not a chloramine; I know about the different chemistry results
****************************************************
Triethanol amine trial in lower amount might be tried but I think the equimolar amount of base and carboxylic acid has a reason to be used.
Maybe pH trimming to avoid side reactions like anhydride formation what might also be interesting intermediary for further purpose as acid chloride
replacement…but not yielding the acid chloride
cyclo(-N=CCl-)3 (s) + 3HO-CO-R (l)--> cyclo(-N=C(-O-CO-R)-)3(s) + 3HCl(g)
HCl being diven away as a gas displacing the equilibrium.
TEA might allow thisone to remain present in the system.
[Edited on 13-2-2008 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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PHILOU Zrealone
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Yep Sauron shame on me....
It was late, I was thinking to Triethylamine (TEA) in the article you attached and I was thinking further about your proposal to reduce TEA amount to
a catalytic concentration; but somehow, I was distracted and wrote Triethanol amine instead ....this should have happened sooner or later when doing
two things at the time....  ... actually i do 20 things at the time at work during
lunch (phone, E-mails, eating, aswering questions and Science Madness reading/answering...
PH Z (PHILOU Zrealone)
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Sauron
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Ah, as I suspected. Why don't you just correct your error, and we can then both delete the subsequent posts, which add nothing to the topic?
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