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S.C. Wack
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PS hexachloro p-xylene and SO2 gives terephthaloyl chloride and thionyl chloride according to US3411886...
Quote: Originally posted by MeshPL ![](images/xpblue/lastpost.gif) | What concerns PCl3, which no one cares about, since it is "impossible" to produce from red phosphorus |
I'm doubtful of anyone saying whatever can't be done, and here for this Thorpe claimed it was easy I've mentioned before in the relevant thread, also
there's that part of Inorganic Syntheses (2, 145) that goes "Two hundred grams of dry red phosphorus is placed in the flask. Excess phosphorus
must be present to inhibit the formation of phosphorus(V) chloride." They found a way and it's probably not the only one.
Quote: Originally posted by zed ![](images/xpblue/lastpost.gif) | Well, one of you clever monkeys came up with this.....AcetylChloride from Acetonitrile, AceticAcid, and HCL gas. |
Mr. Colson. Benzotrichloride and acetic acid gives a mixture of acetyl chloride and benzoyl chloride says US1965556.
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Chemi Pharma
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MeshPL,
you can sinthesize PCL5 easily from red phosphorous in chloroform suspension, bubbling into dry chlorine.
To make PCL3 you just need to reflux PCL5 with stoichmetric amount of red phosphorous at a dry and moisture free apparatus full of a inert gas, like
nitrogen or helium.
See the recipe below:
Attachment: Phosphorus pentachloride.doc (23kB) This file has been downloaded 482 times
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clearly_not_atara
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Quote: | Well, one of you clever monkeys came up with this.....AcetylChloride from Acetonitrile, AceticAcid, and HCL gas. Even made a video demo!
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https://www.thieme-connect.com/products/ejournals/html/10.10...
EtOH (1 mmol) + TCCA (0.75 mmol) + NH3 (45 mmol) (aq) >> MeCN (aq)
It's not practical to make acetonitrile for solvent use -- you'd need a 45x molar excess of ammonia -- but it's fine if you're just gonna make acetyl
chloride. Since it would appear that the formed acetamide is inert to the reaction conditions, you may be able to use other nitriles as well (if
acetonitrile proves to be too hard to separate from aqueous ammonia...).
[Edited on 28-6-2016 by clearly_not_atara]
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Cryolite.
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(forgot my password, waiting for reset email)
There's also www.sciencemadness.org/talk/files.php?pid=69963&aid=1539 , which provides a way to oxidize alpha-amino acids to nitriles using TCCA and sodium
hydroxide. The reaction conditions are mild, the excesses small, and the extractions are easy, and most notably this should provide a way to oxidize
L-alanine (sold as a nutritional supplement) to acetonitrile. Although I haven't seen this particular substrate tested in any of the papers on this
oxidation, the paper does show oxidation of aspartic acid to cyanoacetic acid in 99% yield. (OTC malonic acid maybe?) I don't see any reason for this
to fail for alanine.
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zed
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Some of the guys are inundated with Acetonitrile. Seems it is used as solvent in certain analytical procedures. Can also be produced by the
dehydration of Acetamide.
Still, the point is....Acid Chlorides are hard to come by. Acetonitrile, not so much.
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Melgar
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I think I may go for the thionyl chloride route, since I'll be traveling to a location where I can use every dangerous reagent there is (rich guy with
a home lab, fume hood, the works). So the idea is that I'll buy a bucket of TCCA tablets, drip HCL on them, gas elemental sulfur until it stops
absorbing chlorine and changes color, then set that aside. Next, get a flask full of sodium bisulfate, and heat it until steam stops coming off and
it starts to melt, around 400C. Then send the tube into the sulfur dichloride from earlier, with appropriate suck-back prevention set up, and
gradually heat the sodium pyrosulfate to decomposition (460C or so). Run that through my distillation apparatus just to cool it down and measure its
temperature (SO3 has a boiling point of 46C) then bubble that through SCl2.
A few questions: do SO2, S2Cl2, or Cl2 interfere with the last step of the reaction? According to the wiki page , there are reactions that use
chlorine, consume SO2, and generate thionyl chloride, so it would seem to be beneficial to continue bubbling Cl2 into the mixture after the SO3
bubbling started, no? Would Cl2 have decent solubility in this mixture? Would there be much chance of contamination with SO2Cl2? Supposedly that
needs a catalyst to form, but carbon will do, and SO3 will turn quite a lot of things into carbon. In any case, I'll have to fractionally distill the
end product. Hopefully the fact that their boiling points are only 5K different won't be a problem. In any case, sulfuryl chloride can apparently
turn alcohols into alkyl chlorides among other things, so I wouldn't be disappointed if any came over.
I did find this excerpt from a book on World War I, about diphosgene:
https://books.google.com/booksid=u2U7AwAAQBAJ&lpg=PT166&...
Supposedly they used it to fill shells, because then they didn't have to refrigerate the factories where it was produced. The heat from the shells
exploding would release the phosgene. Anyway, chlorination of methyl formate was the dominant process used by the Germans in 1917, so it can't be
that disaster-prone, right? The fact that you don't have actual phosgene gas at any point is quite attractive.
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careysub
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Quote: Originally posted by Melgar ![](images/xpblue/lastpost.gif) |
I did find this excerpt from a book on World War I, about diphosgene:
https://books.google.com/booksid=u2U7AwAAQBAJ&lpg=PT166&...
Supposedly they used it to fill shells, because then they didn't have to refrigerate the factories where it was produced. The heat from the shells
exploding would release the phosgene. Anyway, chlorination of methyl formate was the dominant process used by the Germans in 1917, so it can't be
that disaster-prone, right? The fact that you don't have actual phosgene gas at any point is quite attractive. |
Although diphosgene is a liquid at RT, with a boiling point at 128 C, unlike phosgene which is a gas at RT, it is NOT SIGNIFICANTLY SAFER THAN
PHOSGENE!!!!!!
Its volatility at RT is 111000 mg/m^3, which is so high it might as well be phosgene. The CUMULATIVE lethal exposure is 3200 mg-min/m^3 so exposure to
a concentration of only 0.15% of its saturation limit in air will sentence you to death in 20 minutes (no treatment exists). And remember you can
accumulate a lethal exposure over the course of a week, in little bits.
It was not the heat from shells that caused the diphosgene to evaporate, it was simply the fact that the explosion disperses it as an aerosol.
Ordinary evaporation turns it into a vapor in seconds.
You have to go to triphosgene to get any significant safety improvement. This form is both actually less toxic that the other two (about 1/6 as toxic
as phosgene) and has a volatility of only 2400 mg/m^3.
[Edited on 6-7-2016 by careysub]
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Melgar
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Quote: Originally posted by careysub ![](images/xpblue/lastpost.gif) | Quote: Originally posted by Melgar ![](images/xpblue/lastpost.gif) |
I did find this excerpt from a book on World War I, about diphosgene:
https://books.google.com/booksid=u2U7AwAAQBAJ&lpg=PT166&...
Supposedly they used it to fill shells, because then they didn't have to refrigerate the factories where it was produced. The heat from the shells
exploding would release the phosgene. Anyway, chlorination of methyl formate was the dominant process used by the Germans in 1917, so it can't be
that disaster-prone, right? The fact that you don't have actual phosgene gas at any point is quite attractive. |
Although diphosgene is a liquid at RT, with a boiling point at 128 C, unlike phosgene which is a gas at RT, it is NOT SIGNIFICANTLY SAFER THAN
PHOSGENE!!!!!!
Its volatility at RT is 111000 mg/m^3, which is so high it might as well be phosgene. The CUMULATIVE lethal exposure is 3200 mg-min/m^3 so exposure to
a concentration of only 0.15% of its saturation limit in air will sentence you to death in 20 minutes (no treatment exists). And remember you can
accumulate a lethal exposure over the course of a week, in little bits.
It was not the heat from shells that caused the diphosgene to evaporate, it was simply the fact that the explosion disperses it as an aerosol.
Ordinary evaporation turns it into a vapor in seconds.
You have to go to triphosgene to get any significant safety improvement. This form is both actually less toxic that the other two (about 1/6 as toxic
as phosgene) and has a volatility of only 2400 mg/m^3.
[Edited on 6-7-2016 by careysub] |
Oh, I wouldn't touch the stuff without a fume hood, and containers of 28% NH4OH sitting out until the room reeked of ammonia. I'd be able to see the
vapors before any of it could get near my airways, not to mention the fact that it'd be neutralized. And of course, it'd all be set up for use in a
closed system. Also, any reaction vessels would be flushed then rinsed with ammonia, and basically I'd always have ammonia handy to quench anything
that started to look bad.
Some people hate the smell of ammonia, but to me, it smells like (relative) safety. It's nice being able to see halogenated nasty shit and acid
vapors before I can smell it.
Regardless, I'd probably only try making it once, and dump anything leftover into (you guessed it!) ammonia once I'm done with whatever synthesis I'd
attempt to use it for.
[Edited on 7/6/16 by Melgar]
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careysub
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Triphosgene can be made by chlorinating dimethyl carbonate (available from Elemental Scientific LLC) with a UV lamp.
That might be safer.
Attachment: eckert1987.pdf (248kB) This file has been downloaded 489 times
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Dope Amine
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Volatile acyl chlorides can be made by distilling a mixture of benzoyl chloride and a given acid. This is my favorite way to make propionyl chloride.
Paraphrasing the experimental procedure - Set up for simple distillation (with moisture protection) a mixture of 2 moles benzoyl chloride for every 1
mole of propionic acid. Aggressively heat (high heat setting) the mixture and a distillate will come over at the b.p. of propionyl chloride. Stop
distilling when the head temperature drops. The article recommends then re-distilling the distillate but I don't bother anymore after having tried
that once. Rather than using a drying tube on the vac intake of the distillation setup, I prefer to run a hose into an IPA solution that I have
stirring. This is because HCl-gassed IPA is a favorite crystallization tool of mine (dissolve freebase in toluene and then add HCl/IPA). The only
drawback of the HCl gassing route is that you'll need to keep an eye on it toward the end of the distillation in order to prevent the eventual
suckback which would ruin your distillate product.
J. Am. Chem. Soc., 1938, 60 (6), pp 1325–1328
[Edited on 19-7-2016 by Dope Amine]
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Cryolite.
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That method works, but the issue is obtaining benzoyl chloride. It can be made by the partial hydrolysis of benzotrichloride, which in turn can be
made by free radical chlorination of toluene, but the benzotrichloride intermediate is extremely lachrymatory and toxic. Even worse, producing the
benzotrichloride must be done by free radical chlorination with a radical initiator (UV light works well), and thefore the synthesis must not be done
very carefully-- free radical reactions can run out of control very quickly.
Despite this, this seems like an otherwise good way to make volatile acid chlorides. I'm pretty sure that benzotrichloride itself can be used to form
acid chlorides equivalently, which will increase efficiency.
Now, the question is: how do we make nonvolatile acid chlorides?
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clearly_not_atara
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I assume the acetonitrile method generalizes to arbitrary nitriles:
RCN + HCl >> RC(NH)Cl
RC(NH)Cl + R'COOH >> RC(NH)OC(O)R'
"" + R'COOH >> RCONH2 + (R'CO)2O
(R'CO)2O + HCl >> R'COCl + R'COOH
So benzonitrile + HCl might work for acyl chlorides which are more volatile than benzonitrile.
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Cryolite.
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That would work (I believe benzonitrile itself can be made from benzoic acid, urea, and sulfamic acid as a dehydrator), but the issue is obtaining
nonvolatile acid chlorides is still off-limits for this procedure, unless a way to separate the acid chloride from the benzamide byproduct is found.
Maybe a solvent in which acid chlorides are soluble, but amides are not?
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Texium
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Now, I don't know exactly what any of you want acid chlorides for, but have you thought about making acid bromides instead? They react in the same way
as acid chlorides in many reactions, and are easier to prepare in a home lab. I would assume that the main reason that acid chlorides are used more
frequently in industrial and commercial labs is because on the commercial scale they are easier and less expensive to prepare.
While PCl3 is very difficult to prepare in the home lab, PBr3 is actually quite easy if you already have bromine on hand. I put
up a video showing the simple synthesis of it a couple days ago: Synthesis of Phosphorus Tribromide
I'm planning to make either acetyl bromide or benzoyl bromide using the PBr3 soon.
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Melgar
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Quote: Originally posted by Cryolite. ![](images/xpblue/lastpost.gif) | That method works, but the issue is obtaining benzoyl chloride. It can be made by the partial hydrolysis of benzotrichloride, which in turn can be
made by free radical chlorination of toluene, but the benzotrichloride intermediate is extremely lachrymatory and toxic. Even worse, producing the
benzotrichloride must be done by free radical chlorination with a radical initiator (UV light works well), and thefore the synthesis must not be done
very carefully-- free radical reactions can run out of control very quickly. |
I've done that reaction, and it can be done with visible light and a catalytic amount of bromine, which can be added in the form of a bromide salt,
and forms bromine monochloride in situ. This allows for lower temperatures and much more even penetration of the light, rather than having it all get
absorbed in the first few millimeters. Thermal runaways are virtually impossible, as long as the vessel stays lit.
Quote: | Despite this, this seems like an otherwise good way to make volatile acid chlorides. I'm pretty sure that benzotrichloride itself can be used to form
acid chlorides equivalently, which will increase efficiency. |
Can't benzotrichloride generate two equivalents of acid chloride? That would make sense, since mixing one mole of benzotrichloride with one mole of
benzoic acid results in two moles (more or less) of benzoyl chloride. Since water will hydrolyze benzotrichloride to benzoic acid, then even if
benzotrichloride is totally nonreactive to anything but benzoic acid and water, it would generate two equivalents of acid chloride. The only thing
you'd have to worry about is side reactions.
Quote: | That would work (I believe benzonitrile itself can be made from benzoic acid, urea, and sulfamic acid as a dehydrator), but the issue is obtaining
nonvolatile acid chlorides is still off-limits for this procedure, unless a way to separate the acid chloride from the benzamide byproduct is found.
Maybe a solvent in which acid chlorides are soluble, but amides are not? |
In that case, it's probably worth the effort to just make thionyl chloride instead. Either phosphorus pentoxide (order from Firefox Pyrotechnics in
the US, make phosphorus halides outside the US) added to sulfuric acid, or heating sodium bisulfate to 460C can generate the SO3, chlorine reacting
with elemental sulfur can generate sulfur dichoride and disulfur dichloride, both of which react with SO3 to generate thionyl chloride.
Quote: | Now, I don't know exactly what any of you want acid chlorides for, but have you thought about making acid bromides instead? They react in the same way
as acid chlorides in many reactions, and are easier to prepare in a home lab. I would assume that the main reason that acid chlorides are used more
frequently in industrial and commercial labs is because on the commercial scale they are easier and less expensive to prepare. |
What magical land is this where people speak with American accents and have easy access to red phosphorus? I assumed you must be South African or
something until I watched the video.
[Edited on 7/21/16 by Melgar]
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zed
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Nice.
Though..... some of the guys at home, have real problems obtaining red-phosphorus.
Well, any kind of elemental phosphorus...actually.
A useful chlorinating agent, can be synthesized via P2O5, when available.
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Cryolite.
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Quote: | I've done that reaction, and it can be done with visible light and a catalytic amount of bromine, which can be added in the form of a bromide salt,
and forms bromine monochloride in situ. This allows for lower temperatures and much more even penetration of the light, rather than having it all get
absorbed in the first few millimeters. Thermal runaways are virtually impossible, as long as the vessel stays lit. |
I remember reading that thread-- thanks for the reminder. From what I remember, the evidence Nicodem provided suggested that a very pure benzyl
chloride product was obtained via Br-catalyzed TCCA chlorination was obtained, but no higher-chlorinated products were obtained. I guess this was due
to the massive excess of toluene used. It might be worth a shot-- I'll try it out if I'm at all free during the weekend.
Quote: | Can't benzotrichloride generate two equivalents of acid chloride? That would make sense, since mixing one mole of benzotrichloride with one mole of
benzoic acid results in two moles (more or less) of benzoyl chloride. Since water will hydrolyze benzotrichloride to benzoic acid, then even if
benzotrichloride is totally nonreactive to anything but benzoic acid and water, it would generate two equivalents of acid chloride. The only thing
you'd have to worry about is side reactions. |
That was what I meant: using benzotrichloride directly as the chlorinator instead of quenching with water to benzoyl chloride. This gives you twice
the overall chlorinating power, improving efficiency. However, going by the intermediacy of benzoyl chloride by reaction with benzoic acid seems like
a good idea, as it is a lot nicer to handle and store than the BzCl-on-steroids benzotrichloride.
Quote: | In that case, it's probably worth the effort to just make thionyl chloride instead. Either phosphorus pentoxide (order from Firefox Pyrotechnics in
the US, make phosphorus halides outside the US) added to sulfuric acid, or heating sodium bisulfate to 460C can generate the SO3, chlorine reacting
with elemental sulfur can generate sulfur dichoride and disulfur dichloride, both of which react with SO3 to generate thionyl chloride.
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I am well aware of this route, but unfortunately I am slightly terrified of SO3, and so producing thionyl chloride in this way is not for me ![:(](./images/smilies/sad.gif)
[Edited on 21-7-2016 by Cryolite.]
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clearly_not_atara
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Quote: Originally posted by zts16 ![](images/xpblue/lastpost.gif) | Now, I don't know exactly what any of you want acid chlorides for, but have you thought about making acid bromides instead? They react in the same way
as acid chlorides in many reactions, and are easier to prepare in a home lab. I would assume that the main reason that acid chlorides are used more
frequently in industrial and commercial labs is because on the commercial scale they are easier and less expensive to prepare.
While PCl3 is very difficult to prepare in the home lab, PBr3 is actually quite easy if you already have bromine on hand. I put
up a video showing the simple synthesis of it a couple days ago: Synthesis of Phosphorus Tribromide
I'm planning to make either acetyl bromide or benzoyl bromide using the PBr3 soon. |
PBr3 is awesome. It is perhaps the reagent of choice when available. There are, however, two important considerations:
* byproduct. PBr3 hydrolyses to phosphorus acid. While harmless at ordinary temperatures, it disproportionates upon boiling to release phosphine gas,
which is highly toxic, and pyrophoric in high concentrations. Reaction mixtures containing spent PBr3 should never be distilled at atmospheric
pressure. This is particularly important since the acyl bromides produced are not usually very volatile.
* raw materials. Phosphorus is illegal.
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Melgar
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Quote: Originally posted by Cryolite. ![](images/xpblue/lastpost.gif) | I remember reading that thread-- thanks for the reminder. From what I remember, the evidence Nicodem provided suggested that a very pure benzyl
chloride product was obtained via Br-catalyzed TCCA chlorination was obtained, but no higher-chlorinated products were obtained. I guess this was due
to the massive excess of toluene used. It might be worth a shot-- I'll try it out if I'm at all free during the weekend. |
I think it also had to do with the fact that the reaction was taking place throughout the whole vessel, rather than just in the edges. This would
tend to make the reaction products more homogeneous.
Incidentally, here is the link to the thread we're talking about, for anyone interested:
http://www.sciencemadness.org/talk/viewthread.php?tid=14063
When I was researching this reaction to see if anyone else had discovered it first, the only reference I found to the use of bromine in the
chlorination of toluene was in Ullman's Encyclopedia of Industrial Chemistry, in the benzotrichloride section, where it mentions that addition of
bromine would assist in the completion of the reaction. For everyone complaining about how difficult it is to fully chlorinate the toluene alpha
methyl, this could potentially make things a lot easier.
Quote: | That was what I meant: using benzotrichloride directly as the chlorinator instead of quenching with water to benzoyl chloride. This gives you twice
the overall chlorinating power, improving efficiency. However, going by the intermediacy of benzoyl chloride by reaction with benzoic acid seems like
a good idea, as it is a lot nicer to handle and store than the BzCl-on-steroids benzotrichloride. |
Good to know that about benzotrichloride. I don't have experience with either of them, so I'm glad to know ahead of time which one of them is least
pleasant to work with.
[Edited on 7/23/16 by Melgar]
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Texium
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Well, if I'm to assume you're in the US, it's not illegal, it's
just that the sale of it within the country is regulated to the point of it being unavailable.
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Melgar
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Quote: Originally posted by Cryolite. ![](images/xpblue/lastpost.gif) | That would work (I believe benzonitrile itself can be made from benzoic acid, urea, and sulfamic acid as a dehydrator), but the issue is obtaining
nonvolatile acid chlorides is still off-limits for this procedure, unless a way to separate the acid chloride from the benzamide byproduct is found.
Maybe a solvent in which acid chlorides are soluble, but amides are not? |
I'm hearing references that phosphorus oxychloride can be prepared fairly easily by heating P2O5 in the presence of a large excess of sodium chloride.
That's essentially the acid chloride of phosphoric acid, correct? If so, that would be ideal for anyone who could get ahold of P2O5, which is
perfectly legal to buy and sell in the US.
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Cryolite.
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That prep is actually in len1's book-- intimately mix dry table salt and phosphorus pentoxide and dry distill at 300+ C. There is etching of the
glass, but without water present it is minor. However, I was under the impression that most acid chlorides cannot be directly made from phosphoryl
chloride. After all, the use of phosphorus pentachloride stops at the oxychloride stage on most substrates.
If you are proposing the use of phosphoryl chloride as a solvent, it would work to dissolve acid chlorides, but just like phosphorus pentoxide it
reacts with amides, forming nitriles. However, this does proceed through the imidoyl chloride stage, just like the use of HCl on nitriles. Maybe in an
excess of the carboxylic acid with a catalytic amount of the amide and a stream of dry HCl gas, phosphoryl chloride could be used to make acid
chlorides. Hmmm...
[Edited on 26-7-2016 by Cryolite.]
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clearly_not_atara
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The preparation of benzonitrile is much easier than the preparation of phosphorus pentoxide or sulfur trioxide (which in terms of handling
alone is already one of the more treacherous things anyone will attempt) since benzonitrile can be had with benzaldehyde + ammonia + TCCA according to
the paper previously posted. This should be particularly high-yielding since benzaldehyde is particularly good at forming imines. Anisaldehyde and
piperonal will also generate usable nitriles, AFAICT.
EDIT: one interesting possibility is to use m-chlorobenzaldehyde to make m-chlorobenzonitrile and m-chlorobenzoic acid and ultimately mCPBA.
[Edited on 27-7-2016 by clearly_not_atara]
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Chemi Pharma
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Clearly,
the link you've posted before goes to nowhere.
I think the paper you're talking about is the one i attached below.![:P](./images/smilies/tongue.gif)
Attachment: alcohols, aldehydes, amines and benzyl halides to nitriles with TCCA + NH4OH.pdf (115kB) This file has been downloaded 766 times
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clearly_not_atara
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^Thanks for catching that. Sometimes links stop working, especially when I find the paper on an academic blog or something and they realize it's being
downloaded
Maybe the nitrile route could extend to oxalyl chloride? I suppose the necessary assumption is that oxalyl chloride won't react with benzamide:
2PhCN + (CO2H)2 + 2 HCl >> PhCONH2 + (COCl)2
Oxalyl chloride is a pretty versatile substance IIRC and not easy to make other ways
[Edited on 19-2-2017 by clearly_not_atara]
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