The pseudonymous "Hpffman" writing in Annalen in a paper elsewhere on this forum, stated that the usual procedure for lab prep of CCl4 was to distill
chloroform in a stream of dry Cl2 while illuminating with direct sunlight.
This is recognizable as vapor phase free radical chlorination with the radical source bing UV photolysis.
In the same paper Hoffman commends the utility of SbCl5 as a chlorinating agent, including for vapor phase chlorinations with Cl2 where the SbCl5 is
employed catalytically.
Therefore, why not distill dichloromethane and dry chlorine through SvCl5 heated to a temperature at or above the bp of CHCl3. The product should
consist of ChCl3, a little CCl4 and some unreacted CH2Cl2.
Run these through again (at least the DCM and the chloroform) until all converted to CCl4.
UV not rquired.
There are roughly 20 C differences between the bps of DCM, chloroform and CCl4. SbCl4 boils higher at well over 90 C..
Ought this not to work?
DCM is after all a lot cheaper than CS2, the other feedstock for CCl4. We might lose a little CCl4 to hexachloroethane but less than with UV
photolysis. No sulfur compounds to deal with. Industrially this process (starting with methane and using UV) has largely displaced the chlorination of
CS2.
Anyone have ideas?
I cannot buy CHCl3 or CCl4. I can buy DCM.
Having already established that SbCl5 is the answer to making CCl4 from BrCCl3, and the same reagent use useful to chlorinate CS2, this is about the
only world left to conquer when it comes to CCl4.
[Edited on 24-2-2009 by Sauron]Arrhenius - 23-2-2009 at 13:53
Sounds nasty... I really don't care to work with fuming inorganic substances. Not to mention the available chlorine may be fairly low from antimony
pentachloride, since I presume after losing one chlorine you end up with an antimony in a lower oxidation state that is perhaps unreactive. The atom
economy of the radical chlorination is probably substantially better.
I'm sorry, I have to laugh a little since you're always concerned about tox issues... but antimony pentachloride is going to be highly toxic (and
volatile), carbon tet is a carcinogen, and chloroform is... well probably not that bad. How much do you need?DJF90 - 23-2-2009 at 14:13
Quote:
In the same paper Hoffman commends the utility of SbCl5 as a chlorinating agent, including for vapor phase chlorinations with Cl2 where the SbCl5 is
employed catalytically.
Therefore, why not distill dichloromethane and dry chlorine through SbCl5 heated to a temperature at or above the bp of CHCl3. The product should
consist of CHCl3, a little CCl4 and some unreacted CH2Cl2.
Sauron has said that SbCl5 may only need to be used in catalytic amounts and the use of dry chlorine should regenerate the SbCl5 as the reaction
consumes it. SbCl5 boils at 140C, which is quite a fair bit above the chloromethanes (CCl4 = 77C, CHCl3 = 61C, CH2Cl2 = 40C)
[Edited on 23-2-2009 by DJF90]brew - 23-2-2009 at 14:42
Anyone have ideas?
I cannot buy CHCl3 or CCl4. I can buy DCM.
I cannot at present put my hand on the file, but I did notice an interesting prep for CHCl3 with 2 phase electrolysis, with reaonable yields -
utilizing NaCl in the aquarius phase and dichlormethane in the more non-polar phase. It basicaly consisted, if memory serves me correctly, of an
undivided cell with the 2 phases maintained, and the aquarius phase having electrodes placed to that depth only, and not touching the lower phase. A
stir bar was placed in order for the lower, dichloromethane to be stirred. Perhaps with longer reaction times, then CCl4 could also be produced. I
will try to find the article. Hopefuly my description hasn't deviated to much from the said article.Sauron - 23-2-2009 at 20:18
DJF90 yes, I actually did read the Hoffman paper, in German as well as in translation.
And I stated above that DCM, chloroform and CCl4 are approx. 20 C apart in bp and indeed, they are 21C and 16 C apart, the point being that no one is
going to say they are too close to fractionate.
I looked up SbCl5 in Acros catalog. Twice actually. bp 92 C. Now I suppose the Belgians could be wrong, and I have no ego invested in this datum. I
will not complain if it boils at 140 C.
My suggestion of passing the vapor of CH2Cl2 admixed w/Cl2 through SbCl5 at a temp above the bp of the product(s) was to drive them off to condenser.
I am not talking about a stoichiometric use of the antimony pentachloride. If I was the injection of Cl2 would not be required. I was merely trying to
design a simple procedure.
Anyway thanks for the comment. I will peek at Brauer to see whether the Belgians are in error.
Indeed Brauer says bp 140 C/760 mm w/decomposition so the Belgians need to sit in the corner and face the wall while wearing a pointy hat.
Sigma-Aldrich says 92 C/30mm so obviously Acros just forgot to mention the diminished pressure.
[Edited on 24-2-2009 by Sauron]benzylchloride1 - 23-2-2009 at 21:56
What is the best way of producing antimony pentachloride as it is a very useful reagent for chlorinations of this type? I have powdered antimony metal
and about 50 grams of antimony trichloride produced from antimony sulfide (stibnite) by heating with hydrochloric acid ouside and then distilling the
residue producing the trichloride. I have a good chlorine generator set up and a fume hood, so the handling of the chlorine would not be a problem.
[Edited on 23-2-2009 by benzylchloride1]Sauron - 24-2-2009 at 01:12
You are all set.
SbCl5 as anyone who has workedmwith it will tell you is a paon in the ass to store. I would therefore store it as SbCl3 and make it in situ as needed.
SbCl3 + Cl2 -> SbCl5
See Brauer, Handbook of Preparative Inorganic Chemistry for details, but it is simple.
The chlorine as usual needs to be dry.
As you know the trichloride is solid and the pentachloride liquid.
One mol SbCl3 will liquify in chlorine and gain 70 g mass so stop when the tared receiver is at the correct weight.
Distill in vacuum, bp 92/30mm but protect your pump, and if you use an aspirator, place a drying tube inline between the receiver and the vacuum
connection.
--------------
Sooner or later someone will say "But what about the haloform reaction?" to get chloroform.
The haloform is fine on a small scale but unweildy on a larger scale, and as lots of us have discovered, unforgiving if you do not adequately control
the exotherm. If that happens the reaction runs away and you lose the mixture out of the flask. Bad bad bad. It is a good way to make 25-50 ml CHCl3
but a bad way to make 250-500 ml, just work out the volumes involved,
If you want liters of CHCl3 and CCl4 then these other methods are the ways to select from.
Halogen exchange with BrCCl3
Chlorination of CS2
Chlorination of DCM and then of CHCl3.
[Edited on 24-2-2009 by Sauron]panziandi - 24-2-2009 at 07:35
Sauron... Another genius method! I myself had looked at dichloromethane to chloroform and carbon tetrachloride. UV chlorination is costly in energy
and a mixture of products.
Catalytic chlorination does sound feasible. And once again it is our lovely friend Antimony doing the dirty work
It would save on CS2 which is incredibly flammable and toxic, and not to say not exactly dirt cheap. DCM is much more readily obtained than CS2 and is
also fairly cheap for a LR and Technical grade which I would imagine would be well suited here as a feed stock.
Giving this a go Sauron? :pEclectic - 24-2-2009 at 08:11
What about catalytic chlorination of tetrachloroethylene?
Cheaper and more available starting material?Sauron - 24-2-2009 at 08:20
Tetrachloroethylene is not importable into this country. Neither is ethylene dichloride, nor ethylene dibromide.
I am not sure about 1,1,3 trichloroethylene, which can be converted to CCl4. Nicodem posted some references and patents on this a while back. IIRC it
is a pressure reaction with O2 and a catalyst.PHILOU Zrealone - 25-2-2009 at 00:21
Quote:
Originally posted by Sauron
I am not sure about 1,1,3 trichloroethylene, which can be converted to CCl4.
-I think you need some sleep
Trichlorethene (trichlorethylene) is by definition 1,1,2 trichlorethene and because there is no other possibility for a trichloro compound of ethene
often the front numbers are excluded...
Maybe you meant a trichloropropene compound?Sauron - 25-2-2009 at 00:43
That is a typographical error not a chemical one.
The Cl2C=CH-Cl is oxidized to trichloroacetyl chloride in a chlorooxidation.
The trichloroacetyl chloride falls apart under chlorination with UV photolysis to give CCl4 and gaseous side products CO, HCl, and a little phosgene
from reaction of Cl2 and CO.
This happens anytime trichloroacetic acid or dichloroacetyl chloride is photolyzed and chlorinated - this is quantitative. . It also happens when
trichloroacetic acid is chlorinated by non-photolytic means, such as with benzoyl chloride, but to a smaller extent. (c.25%) See attached H.C.Brown
article from JACS and references therein. Also see the chloral thread and chloral chemistry review from Chem.Rev. posted there.
I recommend you right-click and use Save Target As...
Left click usually gets a corrupted pdf due to forum software.
[Edited on 25-2-2009 by Sauron]PHILOU Zrealone - 25-2-2009 at 02:26
By the way Sauron,
Because of your interest in halogenated and toxic compounds...
1°)If you warm at reflux trichlorethene with HNO3 69% you get easily a single compound related to chloropicrin (Cl3C-NO2) that is Cl2C=CCl(NO2)
(1,1,2-trichloro-2 nitroethene).
It displays the sharp smel of chloropicrin and is realtively toxic...it reacts with diamines to give FOX related compounds.
2°)Upon H2SO4 boiling of Trichlorethene, one can get as final compound chloracetic acid itself a good source for the synthesis of 1.3 dichloroacetone
(dichloropropanone)...
[Edited on 25-2-2009 by PHILOU Zrealone]Sauron - 25-2-2009 at 04:40
It may surprise you but I have no particular interest in chloropicrin, and no particular interest in trichloroethylene. The latter was suggested by
Nicodem as a shortcut to trichloroacetyl chloride at a time when more facile routes to CCl4 were not yet at hand. Things have changed.
And my interest in CCl4 and CHCl3 is almost entirely a matter of their utility as solvents and occasionally as reagents.
Stupid regulations born of hidebound bureaucracy make us all jump throiugh hoops like these. I do rather enjoy frustrating all that when I can. To a
very great extent I am done with such preliminaries and can now get down to brass tacks.Globey - 25-2-2009 at 18:10
Snip...
Quote:
Originally posted by PHILOU Zrealone
By the way Sauron,
Because of your interest in halogenated and toxic compounds...
His name is Sauron, not SarinSauron - 26-2-2009 at 08:34
Just don't call me late for dinner.
Now let's get back to chemistry.Globey - 26-2-2009 at 12:00
The pseudonymous "Hpffman" writing in Annalen in a paper elsewhere on this forum, stated that the usual procedure for lab prep of CCl4 was to distill
chloroform in a stream of dry Cl2 while illuminating with direct sunlight.
This is recognizable as vapor phase free radical chlorination with the radical source bing UV photolysis.
In the same paper Hoffman commends the utility of SbCl5 as a chlorinating agent, including for vapor phase chlorinations with Cl2 where the SbCl5 is
employed catalytically.
Does anyone know what this reference is about? I cant find any articles on the subject of SbCl5 by either Hoffmann, or the more famous A W Hofmann in
Annalen der Chemie and/or Pharmacie for any year. I dont think this exists.
[Edited on 23-2-2010 by len1]Sauron - 23-2-2010 at 03:18
That is because you are an arrogant ass.
I posted the German original in Wanted References Needed Translations last year and one of the members (maybe formatok) translated it and posted that.
I will be happy to furnish either to any member - but not you. After all you don't need something that "doesn't exist".
"Hoffman" was a frequent PSUEDONYMOUS contributor to Annalen and had no connection with any of the several chemists os same or similar name.
His articlr describes theee exothermic reaction of CS2 and SbCl5 as well as that of CS2 and Cl2 over SbCl3; and more briefly the gas prase
chlorination of ethylene to 1,2-dichloroethane, and of acetyene to 1,1,2,2-tetrachloroethene
- in boyj cases by passimg a mixture pf Cl2 and the hydrocarbon over heated SbCl5.
[Edited on 23-2-2010 by Sauron]len1 - 23-2-2010 at 03:42
It really doesnt matter that you say you wontpost - i have access to the entire annalen and its not there
You can of course write whatever you happen to choose about me, it stands for nought as your 5000+ posts of what you plan to do with no outcome vouch
for your credibility. In contrast I stand behind everything I say.
[Edited on 23-2-2010 by len1]Sauron - 23-2-2010 at 03:47
I can't help it that you don't know how to search.
You are just setting yourself up for a fall, because the paper IS real, and as stated, so upi are going to look foolish and I will be delighted to
administer the blow.
[Edited on 23-2-2010 by Sauron]fractional - 23-2-2010 at 04:28
Thanks fractional for the reference - that was interesting.
I wansnt of course stating that there is no article - I couldnt be sure of that - just what I said - that there is no Annalen article whose author
comes up as Hoffmann/Hoffman etc. on the subject. Sauron - 23-2-2010 at 04:53
Thanks fractional
Here is the original paper by "Hofmann" p264 Annalen 115 (1860)
READ IT AND WEEP LEN1
And as to your frantic backpedaling:
"Does anyone know what this reference is about? I cant find any articles on the subject of SbCl5 by either Hoffmann, or the more famous A W
Hofmann in Annalen der Chemie and/or Pharmacie for any year. I dont think this exists.."
So eat your words along with the crow.
Why not write an Illustrated Practical Guide on How to Open Mouth and Insert Foot.
[Edited on 23-2-2010 by Sauron]len1 - 23-2-2010 at 05:14
Interesting, when you do a search on Annalen (anyone can do this even without access) for Hofmann, this article doesnt come up. Yet when you go to
the contents pages it is there, without attribution to an author, obviously you cant trust Wiley's search engine.
Sauron have you been bitten? Though not recently, its getting worse.Sauron - 23-2-2010 at 05:22
That should come as no surprise to anyone who has spent much time in Wiley's journals. I have complained about this more than once.
I do not recall where I found a citation to this paper nor whether I fished it out of Wiley or from th Emil Fischer collection of Annalen I have on
DVD.
Some may recall I posted that collection in References last year.
[Edited on 23-2-2010 by Sauron]Sauron - 23-2-2010 at 05:27
No, I avoid rabid things such as curs, coons, skunks and you.
You in effect accused me of lyimg about a reference when in fact that reference was real and posted in German and in translation on this very forum.
Thus you make yourself appear an ass.
You proceeded with an ad hominem attack on me, and then when I throw your gauntlet back in your face you wax aggrieved.
Utterly contemptible poltroon! Next time do your homework.
[Edited on 23-2-2010 by Sauron]Panache - 23-2-2010 at 07:59
this thread was about a chemical I believe, well it was once, long ago, perhaps some of you may remember, it whispers to me in the evening
breeze..............quietly............CCl3............CCl4.
Anyway there was an allusion to trichloroacetic acid, actually more of a direct referral to it than an allusion, anyway, i have some but no CCl4, does
it readily react with benzoyl chloride to form the carbon tet of old fables whispered in the wind?Sauron - 23-2-2010 at 09:15
Chlorination of trichloroacetic acid to trichloroacetyl chloride by means of benzoyl cghloride (not benzyl chloride) was reported by HC Brown in a
JACS paper I have posted more than once, to give 10-20% CCl4 along with the acid chloride.
A review on chloral chemistry states that chlorination os TCAA wiyj Cl2 under UV gives complete conversion to CCl4 along with some phosgene.
There are better ways to make CCl4. Starting from GAA or EtOH to get to TCAA is wasteful of chlorine and tedious.
All of this has been discussed in other threads, which see. The topic of THIS thread is supposed to be getting to CCl4 from DCM via CHCl3.
[Edited on 23-2-2010 by Sauron]Eclectic - 23-2-2010 at 09:18
Welcome back, Sauron....please try not to get sucked into petty bickering? The SbCl5 as chlorination catalyst looks interesting and doable. Also
not that hard to obtain OTC....I collected several Kilos of SbCl3-SbCl5 from the H2O2+HCl treatment of the residue left from making SnCl2 by boiling
95-5 Sn-Sb solder in muriatic acid (HCl+H2O). The antimony chlorides seem stable enough to obtain by dehydration of aqueous solutions.
Tetrachloroethylene is easy as dirt to get in USA as brake cleaner or dry cleaning solvent...seems worth a try as well.
[Edited on 2-23-2010 by Eclectic]Sauron - 23-2-2010 at 09:32
SbCl3 is quite cheap and I have no problem obtaining it. Wheel weights (OTC) are Db and are used by bullet casters to harden lead. Preparing SbCl3 or
SbCl5 from the elements is easy, see Brauer.len1 - 23-2-2010 at 18:36
Interesting, when you do a search on Annalen (anyone can do this even without access) for Hofmann, this article doesnt come up. Yet when you go to
the contents pages it is there, without attribution to an author, obviously you cant trust Wiley's search engine.
Sauron have you been bitten? Though not recently, its getting worse.
The author of said article is no pseudonym, it is indeed A W Hofmann of Hofmann rearrangement fame. It is clearly labelled part 3. The previous
article in Wiley is labelled part 2, and the article before that carries Hofmanns name - and is part 1.
If one searches for Hofmann, among the 200 or so hits you get the first part of this article with a completely different subject. The other parts are
listed as separate articles, but with no author.
If one reads what I wrote there is no accusation of lying about the article - I wouldnt have posted my request if I thought there was nothing to it,
at the time I thought the author could have been mistaken, or the publication, hardly amounts to lying. Now that you mention it, there is a
subsequent accusation about lying in 5000+ posts about a multitude of things the poster was about to do, without any of it subsequently materializing.Sauron - 23-2-2010 at 18:53
I'm through with you, liar, and this yj\\thread has returned to chemistry not your spleen.
[Edited on 24-2-2010 by Sauron]Panache - 24-2-2010 at 16:04
There are better ways to make CCl4. Starting from GAA or EtOH to get to TCAA is wasteful of chlorine and tedious.
Yes, however I have some 1500g of TCAA, that i have not even glanced at since acquired some two years back, i guess though it would only make around
500ml CCl4, at best with all things considered.
All of this has been discussed in other threads, which see. The topic of THIS thread is supposed to be getting to CCl4 from DCM via CHCl3.
Touche fine chap!
I however i repel your parry with a deft flourish of my foil (btw that's all my fencing jargon thoroughly exhausted.)
If i used TCCA to further chlorinate my TCAA and published the results i would have to be up for an acronym award of some kind, especially if i
littered the paper with so many TCCA's and TCAA's that one would need some sort of OCD to decipher it.
[Edited on 25-2-2010 by Panache]Sauron - 24-2-2010 at 20:37
You could avoid the acronym muddle by using KMnO4 rather than TCCA as reagent to generate Cl2 from conc HCl(aq).
But I agree that if you have a Kg and a half of trichloroacetic acid that you have no other use for, and you have a need for CCl4 and no good way to
buy same, then UV chlorination of the acis makes sense.
What happens is that Cl3CC(=O)Cl forms and fragments into the Cl3C radical plus CO, and other shards. Are you prepared to deal woth CO and some
phosgene?
The Cl3C radical reacts with Cl radicals present to form CCl4.
There is a monograph on chloral in Chem Rev I posted a few years ago that details this. Chloral is easier to prepare than TCAA for those who don't
have 1500 g on hand.
I think if you search on chloral in the ACS SE for Chem Rev you will quickly obtain the citation, and if you availed yourself of the Chem Rev archive
from alter then you just need to pull it up.
The forum FSE failed to even find the thread.
Chemistry of chloral
F. I. Luknitskii
Chem. Rev., 1975, 75 (3), pp 259–289
Publication Date: June 1975 ()
DOI: 10.1021/cr60295a001
[Edited on 25-2-2010 by Sauron]Sauron - 24-2-2010 at 22:04
In my opinion the main advantage of proceeding from ethanol rather than GAA is that UV is only used in the final scission
rather than throughout.
As long as we are being OT there is perhaps a better employement for your TCAA
There is a patent to Rhone on production of oxalyl chloride.
Prepare the trichloroacetyl diester of ethylene glycol. The patent teaches use of the acis chloride for the esterification.
UV-percglorinate this
Treat with an amine catalyst and voila, (COCl)2
The trichloroacetyl chloride is revoverable almost entirely.
This patent has been posted before in one of the oxalyl chloride threads.
I post it here for convenience.
The problem now becomes the best way to covert your acid to acyl chloride and I commend the Herbert Brown method, i.e. benzoyl chloride. After all the
CCl4 side product is something you want anyway.
A Convenient Preparation of Volatile Acid Chlorides
Herbert C. Brown
J. Am. Chem. Soc., 1938, 60 (6), pp 1325–1328
Publication Date: June 1938 ()
DOI: 10.1021/ja01273a014
Attachment: US4301092.pdf (178kB) This file has been downloaded 786 times
[Edited on 25-2-2010 by Sauron]Sauron - 25-2-2010 at 03:55
I ran across a patent that described prep of tricgloroacetyl cghloride in high yield by chlorination sans UV over GAC from a variety of starting
materials, including acetaldehyde, chloral, acetyl chloride, and dichloroactyl chloride. Both vapor and liquid phase reactions are detailed as well as
atmospheric and pressure conditions.
Scission to CCl4 and CHCl3 is nonzero but usually 1% or less. Never more than 10% for the two combined.
Attachment: US5659078.pdf (102kB) This file has been downloaded 660 times
Eclectic - 25-2-2010 at 04:43
Solo put up a link for "The Chemistry of Chloral" 11-18-09
Note that Brown obtained 88% AcCl with 1.5 mols benzoyl chloride per mo; AcOH while for moomo, di and trichloroacetyl chlorudes the best yields were
76, 73 and 56% respectively and with 2 mols benzoyl chloride per mol acid.
The balance for TCAC and to a lesser extent DCAC is a mix of CCl4 and CHCl3 from scission of the C-C bomd of the acyl chlorides.
[Edited on 25-2-2010 by Sauron]Sauron - 25-2-2010 at 21:33
@Panache
I posted this OT stuff about the Rhone process patent simply because I thought you were interested ub ways to exploit TCAA.
If you are not I will desist.
[Edited on 26-2-2010 by Sauron]Upstream - 17-3-2010 at 18:47
The topic of THIS thread reminded me my schooldays and how happy I was one day when I managed to prepare few cc of CHCl3 by heating a mixture of
sodium trichloroacetate (a popular herbicide in the past) and powdered NaOH!
A very friendly and green approach, BTW. Highly recommended for those who don't like HCl atmosphere and when everything is covered with rust
How much do you need?
