Theoretic
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Catalytic chlorination
What do you think of catalytic chlorination,
with ammonium salts being the catalyst?
1)NH4+ + 3Cl2 => NCl3 + 3HCl + H+
2)3R-H + NCl3 => 3R-Cl + NH3
3)NH3 + H+ => NH4+
which makes chlorinations a piece of cake.
Chloramine could be used for delicate chlorinations (such as monochloroacetic acid from acetic acid) - generated on spot from Cl2 and NH4+ (different
proportion)and with ammonium regenerated!
Or adding chloramine (liquid or dissolved) dropwise.
Sounds too good to be true, tell me what's wrong!
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I am a fish
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The NCl3 generated will collect at the bottom of the reaction vessel. As this is a touch sensitive high explosive , I can see a slight problem...
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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Blind Angel
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Well let me redirect you to an other thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=762
The wrong thing in your too good to be true idea, is that it's sould be made in situ and never moved...
/}/_//|//) /-\\/|//¬/=/_
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Theoretic
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Thanks for redirection! Although...
"The NCl3 generated will collect at the bottom of the reaction vessel."
But NCl3 is a very potent oxidizer, why wouldn't it react as soon as formed?
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Marvin
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"2)3R-H + NCl3 => 3R-Cl + NH3 "
Umm, What makes you think this will happen at all? To what classes of R, alkanes?
"But NCl3 is a very potent oxidizer, why wouldn't it react as soon as formed?"
Based on what evidence? More potent than the Cl2 you are forming it from?
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unionised
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Well, that reaction works for tertiary alkanes according to March's book.
You need a Lewis acid catalyst.
The reacting species is thought to be a complex of the AlCl3 and the NCl3. Appart from anything else, that limits your choice of solvents.
The big problem is that you will probably blow the equipment up. A second problem is that the chloramines are not very nice things to work with.
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Theoretic
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"Based on what evidence? More potent than the Cl2 you are forming it from?"
HUH? Can't oxidizers react to form more potent oxidizers? A very apparent example is hypochlorites, which are extremely potent oxidizers -
stronger than chlorine. Even chlorates are stronger oxidizers than chlorine.
Another thing is that chlorine in a 1+ oxidation state (yes, that's chlorine's oxidation state in NCl3!) is a very powerful oxidizer. I
assume NCl3 is an oxidizer stronger than ClO- because it hydrolyzes into NH3 and HClO (another evidence of +1 chlorine in NCl3) and energy is released
(as in any hydrolysis), so NCl3 is more energetic than HClO (more potent than ClO-).
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Marvin
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unionised, Id hazard a guess that chlorine would also react under the same conditions whereas without a free radical initiator, it wont replace R-H
normally. Put into anhyrous conditions and complexed, its quite possible NCl3 could become quite a strong oxidiser, but under the conditions
described, things look very unlikley.
Theoretic,
"Can't oxidizers react to form more potent oxidizers?"
The reaction does not go forward, you have to force it in the same way water doesnt run uphill.
Catalysts do not work this way either, they provide a mid energy point with a lower activation potential than the process uncatalysed. You are trying
to pursuade us that a reaction will run *downhill* - to a point of *higher* energy and that this point of higher energy will force the reaction
forward.
Except you dont know its a point of higher energy, its a guess you havnt even bothered to check in a textbook, as the following is evidence of :-
"A very apparent example is hypochlorites, which are extremely potent oxidizers - stronger than chlorine"
Wrong.
"Even chlorates are stronger oxidizers than chlorine"
Wrong.
"Another thing is that chlorine in a 1+ oxidation state (yes, that's chlorine's oxidation state in NCl3!) "
Wrong.
"I assume NCl3 is an oxidizer stronger than ClO- because it hydrolyzes into NH3 and HClO "
Faulty logic.
"energy is released (as in any hydrolysis)"
Wrong, though true for most chemical reactions viewed alltogether.
"NCl3 is more energetic than HClO (more potent than ClO-)."
More energetic? More potant? Faster? Higher IQ? Got larger portions of rice pudding at school?
Additionally you seem to be confusing HClO with ClO-, rate of reaction with oxidising potential, ideas for methods, questions for solutions, this
forum as an easier method of turning one into the other than your local library and its starting to irritate me.
Read. More preferably "Chemistry of the elements" by Greenwood and Earnshaw than March.
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Theoretic
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Marvin...
"Read. More preferably "Chemistry of the elements" by Greenwood and Earnshaw than March."
Why, you...  "Chemistry of the elements" is becoming my Bible...
"Theoretic,
"Can't oxidizers react to form more potent oxidizers?"
The reaction does not go forward, you have to force it in the same way water doesnt run uphill."
It's true that at the pH of the reaction the products are weaker oxidizers than the reactants, but if you change pH a lot, spectacular things
happen. The ferrate ion is made using hypochlorite, whose oxidizing potential is WAY below ferrate's in acid solution, but in alkali ClO- is used
to prepare FeO4--.
""A very apparent example is hypochlorites, which are extremely potent oxidizers - stronger than chlorine"
Wrong. "
You're right, I'm wrong. 
"confusing HClO with ClO-"
Not really, since in acid solution the latter is transformed into the former (which has higher potential though).
""Even chlorates are stronger oxidizers than chlorine"
Wrong."
Why, you... Chlorine's potential is 1.35 V, chlorate's potential is
1.47 V.
""Another thing is that chlorine in a 1+ oxidation state (yes, that's chlorine's oxidation state in NCl3!) "
Wrong."
I don't think! How come then NCl3 hydrolyses into NH3 + 3HClO and not into HNO2 + 3HCl? During hydrolysis of a compound the element's formal
oxidation number is unchanged. And nitrogen's electronegativity is ever so slightly bigger than chlorine's...
"Additionally you seem to be confusing... rate of reaction with oxidising potential"
Maybe, because untill now I somehow assumed that ClO- is a more potent oxidizer than ClO3- (which it isn't) ... or in theory anyway, since HClO
(produced by hydrolysis of ClO- in aqueous solutions) HAS got a higher oxidizing potential (1.50 V) than ClO3-.
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unionised
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Chlorate can oxidise chloride to chlorine, and does so (granted with the evolution of some oxides of chlorine, but that hardly disproves the point)
reasonably readily.
Hypochlorite can also do this. Chlorine can only just oxidise chloride to chlorine. (Yes, I did mean that. If you bubble chlorine through
radiolabeled HCl you get some exchange and the radiochlorine comes out in the gas phase.)
It looks like hypochlorite and chlorate are better at oxidising than chlorine.
OK, next question... how are they made?
Answer... from chlorine.
Now look at the effet of pH and you will find that, in alkaline conditions chlorate and hypochlorite won't oxidise chloride to chlorine.
Perhaps people should read both books.
If I wanted to halogenate toluene I might use the ferric halide as a catalyst. The FeX3+ X2 catalyst is a better oxidant (for this set of conditions)
than the halogen I made it from. That's the whole point of adding the catalyst. Which way is uphill? towards the better oxidant or towards the
separate halide and halogen?
At any rate it would be easier to use a safer intremediate than NCl3
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Marvin
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Theoretic,
I find "chemistry of the elements" too similar to other uni inorganic books for me to consider it a bible. It is a lot better for werner
complex chemistry, and discussion of redox.
"It's true that at the pH of the reaction the products are weaker oxidizers than the reactants, but if you change pH a lot, spectacular
things happen."
Yes, you send the reaction backwards to chlorine. Unless you isolate, and then acidfy in which case you force creation of a stronger oxidising agent.
The important thing here though is the reaction is running downhill unless you force it the other way by making that the new downhill.
"The ferrate ion is made using hypochlorite, whose oxidizing potential is WAY below ferrate's in acid solution, but in alkali ClO- is used
to prepare FeO4--. "
I have a better example. If you make MnO2 alkaline enough, it will absorb oxygen from the air and turn into manganate(VI). When you make this acid,
it disproportionates into Manganate(VII) and MnO2. Now because you are aparently 'making' it from oxygen, would it be fair to say that
oxygen therefore is the stronger oxidising agent, or that permanganate is and you are forcing the reaction externally?
"...in acid solution the latter is transformed into the former (which has higher potential though). "
In alkaline solution HClO essentially doesnt exist, and in acid solution ClO- essentially doesnt exist. This is a big difference, and the difference
in oxidising potential between acid and alkali solutions is huge.
"Chlorine's potential is 1.35 V, chlorate's potential is 1.47 V. "
This is correct for 1M acid solution, but its not true for neutral solutions and its not true for basic solutions. Since its not generaly true the
statement is not true. More importantly, where you were going with your argument was essentially 'Chlorine makes chlorates, and they are
stronger oxidising agents than chlorine', except under all conditions chlorine does make chlorates they are a less strong oxidising agent. This
is why the statement is completely wrong in your context.
"During hydrolysis of a compound the element's formal oxidation number is unchanged."
Perhaps youd like to explain that to polysulphide ions, the halogen gasses, tha alkali metals and anything else capable of finding a back door in high
school chemistry.
"How come then NCl3 hydrolyses into NH3 + 3HClO and not into HNO2 + 3HCl? "
You are placing a great deal of faith in a model for compounds at the other extreme end of bonding to that which NCl3 uses. Formal oxidation state is
of limited use at the very best of times in my experience. To me it seems more of a preuniversity teaching tool and method of naming compounds than a
means for working out how something unknown should react. I have to admit at this point, I was under the impression that chloramine would hydrolyse
with alkali to hydroxylamine, and this does not seem to happen.
"And nitrogen's electronegativity is ever so slightly bigger than chlorine's."
Depending on who you read, and most people use Pauling's scale, chlorine is higher than nitrogen. Since you are under the impression this is not
the case, I'm guessing you are using Alled and Roschow.
If you ask the question, if a nitrogen atom next to a chlorine atom had to ionise, which way would it go?
Youd find the most stable form would be N+ Cl- becuase the ionisation energies are similar, but chlorine has a high electron affinity, whereas
nitrogens electron affinity is virtually nothing.
Lastly the 'accepted' state of affairs for naming the compound is 'nitrogen (III) chloride', with a formal charge of +3 on the
nitrogen and -1 on each chlorine. A trip to webelements will confirm this, though its not clear from which of their references they got it from.
My conclusion about the oxidising strength of NCl3 is that it has to be less strong than chlorine becuase its formed in high yeild from chlorine. If
we swing the reaction towards high pH, is the oxidation potential of the NCl3 really going up, or is it just the potential of the hypochlorite ion is
dropping so rapidly this becomes the prefered form in basic solution? NCl3 does not seem to be a strong oxidising agent, and strong oxidising agents
are not what we need to speed up reactions anyway.
If this thread was your intended 'chlorination without substitution thread' I have more bad news btw 
It would be interesting to know what dilute NCl3 would do to double bonds, and if this could be useful. This at anyrate would really not be
substitution.
unionised,
"Chlorate can oxidise chloride to chlorine...
And the reverse can also happen, you are making the same mistake. You are changing the conditions, telling yourself that is only a very minor
alteration and that the resulting change of oxidising potential is therefore 'free'. Catalysis does not work like this, it cannot work like
this.
What I think you are thinking is that the AlCl3 is making the NCl3 a 'stronger oxidising agent'. This is possible in this case, but if true
it wouldnt be catalysis, the AlCl3 would be used up, as adding just NCl3 would not be able to regenerate the adduct from the waste products of the
reaction. What is also possible, and how catalysts work is they lower the activiation energy instead, usually by stabilising the intermediate
'high energy' state that limits the rate of the reaction.
The point that lewis acids catalyse halogenation of arenes is a good one, but what is required for this isnt a better oxidising agent, its
electrophilic bromine. If it was about oxidising strength it wouldnt go any faster.
"Which way is uphill? towards the better oxidant or towards the separate halide and halogen?"
Uphill is to higher energy, in this case towards the production of a small population of electrophilic bromine.
I agree that NCl3 is not suitable for these sorts of home experiments.
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unionised
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AlCl3 is usually thought of as a catalyst in the Friedel-Krafts acylation of arenes. The trouble is that it reacts with the product (the ketone) to
form a complex and so you need a stoiciometric ammount of it. In this case the AlCl3 would react with the NH3 produced. Nevertheless I still think it
counts as a catalyst for the reaction.
The complex of AlCl3 with Cl2 can be formulated as [AlCl4]- Cl+
Cl+ is a better oxidant (and electrophile) than Cl2
Writing that structure as fully ionised is pushing the definitions of ionisation a bit, but the polarisation of the halogen by complexation certainly
makes it a better oxidant.
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Theoretic
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Marvin:
""During hydrolysis of a compound the element's formal oxidation number is unchanged."
Perhaps youd like to explain that to polysulphide ions, the halogen gasses, tha alkali metals and anything else capable of finding a back door in high
school chemistry."
Alkali metals? Halogen gases? I SAID A COMPOUND! And more, you seem to be confusing redox reactions (alkali metals or fluorine + water) and
disproportionation reactions (halogen gases + water) with hydrolysis. DO read. Polysulfides? Sorry for not being specific, I actually meant hydrolysis
of bonds between different elements.
"In alkaline solution HClO essentially doesnt exist"
Well, solutions of hypochlorites do hydrolyse, don't they? And they create an alkaline pH, right? And what is the product of hydrolysis if not
HClO? The fact that hypochlorite solutions are such strong oxidants is because of the self-created HClO they contain, ClO- ions are themselves weak
oxidants. Another thing if you mean ALKALINE alkaline solutions (the standart pH of 14 created by NaOH). Under such conditions yes, hydrolysis is
hindered and all HClO that was in solution reacts. The resulting solution is a much weaker oxidant than simple hypochlorite.
"It would be interesting to know what dilute NCl3 would do to double bonds, and if this could be useful. This at anyrate would really not be
substitution."
I say: add across them! Then either the resulting intermediate hydrolyses to dichloroamine and chlorohydrin, or the reation takes on an altogether
different path. Sulfur dichloride (SCl2) is known as a reagent in preparation of mustard gas (S(CH2CH2Cl)2) by its addition to ethylene, so I suspect
NCl3 would behave the same way - by forming tri-2-chloroethylamine (N(CH2CH2Cl)3). A third pathway might be addition of NCl3's chlorine to the
double bond and evolution of free nitrogen.
I've been talking about C=C bonds. I leave C=N, C=O, C=S and others to someone else.
And I don't see why NCl3 would pose a significant ristk if it would be generated a little at a time and (I hope) reacted as soon as generated? It
can react slower than we want, thus accumulating, though.
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The nitrogen mustards are not nice chemicals so I would be careful about adding NCl3 to alkenes.
What this thread amounts to is;
It might be possible to chlorinate some tertiary alkanes by forming NCl3 by chlorination of ammonia, isolating it in solution in some innert solvent
(perhaps CH2Cl2) drying it , adding a lewis acid catalyst and using this to chlorinate the alkane.
I dare say there may be instances where this would be useful, but I can't think of any off hand. In the mean time you risk the toxicity of the
chloramines, the explosive nature of the NCl3 and, if there are any alkene impurities (or by products) the carcinogenicity of the nitrogen mustards.
Interesting and probably no more hazardous than quite a few of the reactions considered on this site.
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Theoretic
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What I mean is bubbling chlorine through a solution of the chemical to be chlorinated, together with some ammonium salt. The idea of extracting NCl3
in a solvent then using it so as to carry out the chlorination with much less bother is very good.
But why only tertiary alkanes?
For NCl3 preparation I recommend Ca(ClO)2 + ammonium carbonate... Oh sorry, my science teacher is looking over my shoulder. How rude...
Anyway, then add a sourse of CO2 to precipitate out alkaline Ca(OH)2 as neutral carbonate. You can use excess AC (ammonium carbonate), but that makes
unpleasant ammonia solution. Ca(HCO3)2 is ideal, NaHCO3 less so, although acceptable, if enough is used, Na2CO3 is unacceptable since the aim is to
neutralize the solution. This greatly improves the yield, (three times, I assume, by loking at the equation)esspecially looking at the fact that the
Ca(OH)2 produced will sink to the bottom of the NCl3 layer, performing evil things...
And I don't think you need to dry it, since no water would be extracted into the inert organic solvent.
Then, if you want an all-out chlorination, add the organic compound to the NCl3 solution slowly, dropwise. If you are afraid for the integrity of your
organic molecule or don't want an all-out chlorination, then add NCl3 solution dropwise, slowly.
Have fun! 
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Marvin
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unionised,
"AlCl3 is usually thought of as a catalyst in the Friedel-Krafts acylation of arenes. The trouble is that it reacts with the product (the ketone)
to form a complex and so you need a stoiciometric ammount of it. In this case the AlCl3 would react with the NH3 produced. Nevertheless I still think
it counts as a catalyst for the reaction. "
AlCl3 is clearly a catalyst becuase it also works for products where a ketone is not generated and the stable adduct doesnt form, so I agree with this
result, but not the more general 'makes things go faster' label you want to apply to a 'catalyst'.
Taking the more general interpretation, I should be able to turn carbon and oxygen into a universal catalyst, simply by burning the carbon in the
oxygen and using the heat to speed up a reaction. This isnt proper catalyctic operation though becuase its only being used to generate energy, and
cant be got back afterwards. Its thermodyamic acceleration. The energy cant be retrieved becuase the reaction that went forwards to liberate the
energy in the first place wont spontaniously go backwards, or it wouldnt have gone forwards at the start. This problem applies to any method of
thermodynamic acceleration.
Theoretic,
"I say: add across them! Then either the resulting intermediate hydrolyses to dichloroamine and chlorohydrin"
I'm sure you do say that, its possible..... In aq solution though I would be less surprised if the reaction was dominated by hydrolysis to
hypochlorite followed by addition of that to the olefin in the same way aq N-Bromo-Succinimide is used to make bromohydrins. NBS is also used as a
free radical source is some reactions, which depending on the circumstances could have useful, or explosive results for NCl3.
"you seem to be confusing redox reactions (alkali metals or fluorine + water) and disproportionation reactions (halogen gases + water) with
hydrolysis. DO read. Polysulfides? Sorry for not being specific, I actually meant hydrolysis of bonds between different elements. "
No, you seem to be assuming that hydrolysis cannot involve a redox reaction. A required assumption for your formal oxidation state claim, and wrong.
Water is both an oxidising agent and a reducing agent. How about reaction of Calcium hydride with water, or do you plan to add furthur
'exceptions' to the list that does not apply? If so then it would also have to include the reaction of Xenon tetrafluoride with water
resulting in the changes of oxidation state of more than just same element bond forming. And when you suss that one out along comes the hydrolysis of
alkali/earth silicides to really ruin your day, very clearly a complete reversal of formal oxidation state for silicon. I'm also fairly sure
that if someone looked for examples in the lit, they'd find cases where formal oxidation state 'swapped' for kinetic, rather than
thermodynamic reasons. Especially for covalent molecules where formal oxidation state nolonger has a real basis in energetics.
"Well, solutions of hypochlorites do hydrolyse, don't they? And they create an alkaline pH, right? And what is the product of hydrolysis if
not HClO? The fact that hypochlorite solutions are such strong oxidants is because of the self-created HClO they contain"
By convention we assume 'HClO' to be a solution of the acid. We assume 'hypochlorite' to be a solution of the salt. If someone
sold me a bottle of 'hyperchlorous acid' and actually gave me a bottle of bleach on the basis that 'well all of the hypochlorite ions
will be protonated at somepoint or another', Id probably make him drink it. The individual oxidation potential of molecules does not concern us,
it doesnt affect the thermodyanics of the solution. What we are interested in is the is the cumulative effect of everything on mass. Bulk solution
values. You seem to be implying that since HClO is present in hypochlorite, that the bulk solution will have the same oxidising power as hypochlorous
acid itself. This is rubbish. If this is not what you meant, you will have to explain in more detail, as I cant make any other interpretation work
in context.
"What I mean is bubbling chlorine through a solution of the chemical to be chlorinated, together with some ammonium salt. "
Yes we know what you mean, and as you seem to be wilfully unaware this entire thread has been devoted to the manifold reasons why it wont work and
shouldnt be done.
"But why only tertiary alkanes? "
Becuase they are the easiest and more importantly, the only ones we have any evidence over guesswork that can be made to work at all. Even this under
very different and rather forced conditions.
"For NCl3 preparation I recommend Ca(ClO)2 + ammonium carbonate... "
Yes, because you havnt read any of the literiture about making NCl3. You dont know why this is a bad choice and from the comments in this post alone
is seems unlikley youve ever actually made any NCl3 successfully yourself.
"Anyway, then add a source of CO2 [huge amount of garbage snipped]"
Why are you doing this? Its completely pointless chemically. If you want a good synthesis of NCl3 in an organic solvent, you look up the one in
inorganic synthesis and use or adapt that. You dont invent one yourself from nothing and then start telling other people how good it is or you end up
making gaping mistakes that show you havnt even tried it. Not unlike the mistakes you have made.
"And I don't think you need to dry it, since no water would be extracted into the inert organic solvent"
Yeah, absolutly, dry an organic solvent? Noone ever does that in a real lab now do they.
Id simply quote "I dont think" and add a comment like 'Maybe this is the problem', but it wouldnt be true. The fact is, thinking
is all you do do and you dont have enough information or experience to get answers this way.
"Have fun!"
You are suggesting people have fun trying something you havnt tried, havnt researched, probably doesnt work, almost certainly doesnt help, could lead
to toxic byproducts and at the very least is dangerously explosive. Great. Wonderful.
Thankyou for giving us the benefit of your inexperience.
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Theoretic
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OK, I DIDN'T prepare any NCl3 (or even tried it). But...
Quote:
"Thankyou for giving us the benefit of your inexperience."
Yes, I don't experiment, I just talk. The "have fun" bit was
inconsiderate, and I know a (maybe essential) minimum about making NCl3, the reaction is unpredictable and dangerous (both the making and reaction of
NCl3), but someone on E&W did succesfully prepare NCl3 by AC + bleaching powder, that's why I assumed it would work again... ...the person obviously didn't read any literature about making NCl3, and it
was a bad chice, but it worked.
And OK, it was an out-of-the-deep-blue-sea assumption of mine that NCl3 reacts with organics in a desirable way.
Do compounds with a N-Cl bond generally work well as chlorinators? Trichloroisocyanuric acid can be made by Cyanuric acid + chlorine, then, if the
reaction goes the way we want, CUA is regenerated... Or are N-Cl compounds generally useless and should never be let to touch anything organic but
tertiary alkanes? 
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Thanks for pointing out the fact that reactions are generally faster with hot reactants; I'm sure that, like me,all the other folks on this
board, didn't know that.
Now look at what I said. The AlCl3 catalyses the acylation reaction. That makes it a catalyst. The fact that it subsequently reacts with the product
does not detract from this. It does this by reacting with one of the reactants to form an intermediate that reacts more quickly with the other
reactant than the original material would. In this case it forms a complex with the acid chloride that acylates the arene faster than than acid
chloride would do.
If you accept that NCl3 is formed from NH3 and Cl2 and that it reacts with the alkane quicker than the chlorine does (which is doubtful) and that it
is converted back to NH3 in this process then it is doing the same job as a castalyst and I don't see what is wrong with calling it one.
The problem is that you need to add a lewis acid to get the NCl3 to react and that will be nobbled by the product. Its just possible that some zeolite
or molecular sieve has an acidic site that would catalyse the NCl3 + alkane reaction but be unaffected by the ammonia (I doubt it, but that's not
the point) then the reaction would work with the NCl3 acting as a catalyst. It would be diffiult to see what else you could call this system (NCl3 and
"magic zeolite" apart from a catalyst or a catalyst and an activator.
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Theoretic
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"If you accept that NCl3 is formed from NH3 and Cl2 and that it reacts with the alkane quicker than the chlorine does (which is
doubtful)..."
The purpose of NCl3 formation is to shorten chlorine bubbling time and spred chlorine evenly throughout the volume and generally to make the reaction
go faster not because of greater chemical reactivity, but because it has a higher "surface area" (chlorine is in form of bubbles, so the
area of contact is low, NCl3 is spread throughout, so the term "surface area" is inapplicable). Compare the reaction of powdered and mixed
ingredients and of those in solution.
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Mood: No Mood
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Unfortunately, it doesn't dissolve in water very well.
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Theoretic
National Hazard
Posts: 776
Registered: 17-6-2003
Location: London, the Land of Sun, Summer and Snow
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Mood: eating the souls of dust mites
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"Unfortunately, it doesn't dissolve in water very well."
True, and it's a godsend for those mad enough to make it. Surely it would be nice having any limbs left after distilling a NCl3 solution?
What I said applies for chlorinations in an organic solvent (which tend to dissolve the organic compound to be nitrated, which is very useful) - as
you say:
"It might be possible to chlorinate some tertiary alkanes by forming NCl3 by chlorination of ammonia, isolating it in solution in some innert
solvent (perhaps CH2Cl2) drying it , adding a lewis acid catalyst and using this to chlorinate the alkane."
[Edited on 30-11-2003 by Theoretic]
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