mfilip62
pierced by a crossbow under a bridge while eating Billy goats
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Registered: 25-8-2006
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POCl3,Acyls,Anhydrides,AlkalyMetals and Halogens
Greetings
I haven't beeh here a LOOONG time and I hope you guys can help me out with something that was bothering me since I got some chemicals
but still can't get others I need (nut I think they migh be abtaibable from those)
SO,before anything,I need to know more about few unlikely chemicls I have,mainly POCl3 and Acyl Chloirides
(Unfortunately I don't have "SOCl2/SOBr2" or "PCl3/PBr3",and for those who mix SOCl2 and POCl3;SOX2 and PX3/PX5 are source of Ionic Halogen
(X=Cl,Br,even I)ideal for the (hydro)halogenatio of unsaturated bounds and relpacing -OH gtoups while releaseing SO2 and unreacted HX as gas.
POCl3 isn't different at all in structure and hydrolysis product,so it's mistery why does it behaves as strange and different as it does!
POCl3 and SOCl2 apperas to follow nearly the aquvalent hydrolysis equilibrium,giving HaloAcid and Mineral Acid(at least it's gas precursor):
SOCl2 + H2O -› 2 HCl + SO2
POCl3 + 3 H20 -› 3 HCl + H3PO4
But instead (hydro)Halogenating,POCl3 dehydrates most supstrates
(like R-OH to Alkene in presence of pyridinium,
and some akldehyades,oximes and amindes into Nitriles(no much info on this!) or for exdample,the way I saw being used sucesefuly ad in great yields
with NAAA and o-toluinidine into Methaqualone much faster
and w/o charing,MUCH more effective than simmilar (poly-)phosphoric scid(s) used in this role!
BUT instead of (hydro)Halogenating most supstrates like SOX2,POX3,POX5 this strange chemicall (POCl3) act as dehydrationg agent that then,even more
confusing,forms
triarylphosphate esters with stericaly undemanding organic Supstrates while HCl is liberated.
So,regarding POCl3 and it's use with some chemicals that migh be interesting to us I googled,and googled,searched in libraries and
asked whoever I could and no one seems to know much!
Those Are THE IMPORTANT QUESTIONS I was asking:
->If you add simple Carboxylic Acid (like Acetic,Propionic,Butric)
or Acyl Halogen(Acetic Chloride and similar) or combination of
both with right amount of POCl3... will you get Anhydride(s)!? I do kinow that Acetyl Chloride was discovered when some French chemist reacted Na or K
Acetate with POCl3!!! So...
->IS there a good,written,QUANTITATIVE method of reacting Na,K or Ca Acetate or Propionate with POCl3 to get coresponding Acyl Chloride!?
I have a lot of POCl3 along with bag od ButricNa and PropionicNa ordered!
So I was interested If I could save myself time and chemicals and make Acyl Chlorides directly instead of distilling Acids first!
I found in some book long time ago and mentioned here on Sciencemadness (along with dead/outdated refference links) that Carboxylic acids are only
substrate where POCl3 is in fact supperior in making both Acyl Chlorides and Acid Ahnydrides from Carboxylic acids than SOCl2/PCl3! Does anyone know
ANYTHING USABLE about it!? ANY REFFERENCES!?
->Can you get Carboxylic ANHYDRIDE (Acetic,Propionic or even gihere ones) by react coresponding Acyl Halogen (Propionic Chloride for example) with
1 or even 2 molar amounts of AlkalyMetal or EarthAlkalyMetal to get anhydride(Lithium in this case)!? If so,do you need to use some kind
of inert solvent (which one would it be!? Et20,Hexan...!?)
What do you think stochiometric amount should be!?
2:1 in favour of AlkalyMetal as most coupling reactions demand or 1:1!?
If you could help me out with data and refference here I am willing to do the experiement and post the results here using elementar Li and Acethyl
Chloride now and later using some other Acyls with Na or K!
->Would the combination of 50:55 stochhiometric ammount of AcCl an Calcium or Sodium Propionate (which one is better!?)
followed by destructive distillation yield some kind of AcethylProphyonil Anhydride!?
Also,will this "classic" method of producing Acethyc Anhydride work to make strainght pure Prophyonil Anhydride if one distill/reacts Prophyonil
Chloride (or other Halide) with Na or Ca Propionate!?
->Are there more refferences on the coupling/reacting of such Halogenated Acids(Acyls actualy) to make Anhydride!
AND MUCH MORE INTERESTING AND ORIGINAL QUESTIONS:
-> Elementar Iodine!? What does one get if he reacts POCl3 and elementar I2!? and how!?
Is this an efficient method of producing usable HI complex or HI gas or not!? Again,any references?!
Since (Hypo)phosphorous (and possibly various other phosphorous acid!?) are used in preparation of HI,I don't see the reason why not to make it this
way!I know what you think,it's crazy waste of the chemicals,but unforetunately,
POCl3 is THE only chemical among the bunch (SOX2,PX3,PX5) I can ge so far!
->Reacting POCl3 with MBr(NaBr/KBr) or MI (NaI/KI) !!!
So,how about reacting MBr/MI with POCl3 !?
I do know that HBr in GAA is extremely usable and one project I am working on (straight-forward Markoniko haloIodation over terminal allylic
double-bound while avoiding dehydrocyanation on the another par of the molecule) cals for conc. HI in GAA and I was thinking...
So....Can one,somehow make HI or HBr in GAA in situ by reacting POCl3 and NaX in AcOH or AcOCl or Ac2O to get concetrated HaloHydrogen in GAA (conc.
anhydrous Acetic acid)!? With or w/o inert solvent,followed most probably by distillation to get rid of H3PO4!
I mean,there are possiby other methods of doing the same thing but efficient or even in situ method of preparing conc. HX in GAA in OTC conditions
would be cool to know!
* BTW if someone can give me some refferences on both properties and use of HBr and HI in GAA please do so! I know that many reactions call for it(for
example,it's much efficient for demethylation of codeine then water solution) but I have no idea why is HydroHalogen in GAA generaly usead and where
is the real difference between the two:HX in GAA and HX in Water solution and how to decide what type of reactions require HX in which solution!? 
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Melgar
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There are a lot of questions there, and you use strange abbreviations for things and jump around a lota with your lines of questioning, such that it
makes my head hurt to read that. However, on the off-chance that you're attempting to make methamphetamine, you should probably just stay with
whatever source you currently have. Fair enough?
If you're trying to make acid anhydrides from acyl chlorides, the way to do this is usually to just get the regular alkali salt of the acid. (ie,
sodium acetate) and react that with an equimolar amount of the acyl halide. It may be possible to do this without the use of solvents, but I'm not
100% sure.
Reacting acyl halides with alkali metals will actually reduce them to the alcohols, in protic solvents. However, if the solvent is inert, you
apparently get "enediol esters", which is something new that I learned. I doubt that this is something that you'd want, but it may be interesting to
know.
Here is a paper on acyl chloride reactions, so you have some reading material now. If there are any questions that you have that haven't been
answered, please ask them again in a way that it's more clear what your question actually is, okay?
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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Nicodem
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Thread Moved
30-7-2017 at 11:40 |
Loptr
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I would try posting coherent directed questions as posts, and not throw in the entire kitchen sink.
This is hard to read and sounds very manic. I guess it is Monday, though.
[Edited on 31-7-2017 by Loptr]
"Question everything generally thought to be obvious." - Dieter Rams
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mfilip62
pierced by a crossbow under a bridge while eating Billy goats
Posts: 140
Registered: 25-8-2006
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Mood: I like turtles!
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Yeah,
You are right,I put too many things together...as you said! Monday!
And no,I don't deal with meth...
It is the one drug that I trully hate!
Anyway,thank you for describing up the AlkaliMetal reaction with Acyl Chlorides I had in mind,but I was really hoping for the coupling to happen...
Maybe it could be done if you reacted Acyl Halides w/o solvent or some "special" solvent and something milder perhaps,like Callcium(0) instead of
Na(o) or Li(0)!
Maybe OrganoIndium,OrganoCopper and OrganoZinc reactions would work here,who knows!
I was also wondering if reacting Na or Ca Propionate salt with Acethyl Chloride by distilling it would make mixed AcethylPropionyl Anhydride!?
I hear that working with Propionic Acid and higher ones ("fatty" ones) is much much harder than working with Formic and Acetic species!
Anyway,fatty Acid Anhydride is what I am working on...
So,reacting EthylLithium or EthylGringard with CO2 migh do the trick
to get Propionic Acid at least! It's cheap enough for me
if I don't menage to get Na and Ca Propionic salts.
I know,it's weird that I find OrganoMetal reagents more readily available than Propionic salts,but it is what it is here! Anyway,it's a good method of
lenghtening a molecule/OrganoHalide by one Carboxyl or Carbon group!
But my most important question was;Can I employ POCl3 somehow to make Acid Halides and even Anhydrides from Carboxylic Acids!?
That's what bothers me most...
PCl3,SOCl2,S2Cl2,PX3,PX5....they all can do the same trick but there is NOTHING I can find on the chemistry of the POCl3!
I mean,not a single good paper! It's frustrating...
But as the powerfull dehydrating agent it should be able(in theory at least) to make Anhydrides!
Right!?
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Melgar
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No, POCl3 won't make anhydrides. It's the acid chloride of phosphoric acid, which is not a very strong acid at all. And despite phosphoric acid being
so resistant to boiling, POCl3 boils at just slightly hotter than water, so you can't exploit differences in boiling points to separate them.
Not every strong dehydrating agent can make anhydrides. Sulfuric acid, for one. Also, any dehydrating agent that's a base.
[Edited on 8/4/17 by Melgar]
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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Crowfjord
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Phosphoryl chloride can react with acids or their salts to make the corresponding acyl chlorides, and anhydrides can be made by combination of acyl
halides and the salts of the acids, so it stands to reason that the anhydrides can be had by using more of the salt, carrying out the two reactions
in situ. Acetyl chloride was first made from potassium acetate and POCl3 by Gerhardt (Ueber wasserfrie organishe Sauren, pg 112). Sodium acetate should work, too.
2 AcONa + POCl3 --> 2 AcCl + NaPO3 + NaCl
AcCl + AcONa --> AcOAc + NaCl
combines to
4 AcONa + POCl3 --> 2 AcOAc + NaPO3 + 3 NaCl
Prepchem also gives a procedure.
[Edited on 5-8-2017 by Crowfjord]
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