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ScienceSquirrel
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Aliphatic halogenated solvents and reactive metals are always a bad idea.
Chloroform explodes when mixed with quite a few eg aluminium,
magnesium, sodium, lithium, potassium, iron and zinc!
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Vogelzang
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Has anyone here tried aluminum in the Friedel-Crafts reaction? See attachment.
Attachment: JCE1989p0176Friedel-Crafts-Al.pdf (1.4MB)
This file has been downloaded 1220 times
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Sedit
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Over at The Vespiary some time back a member I believe it was V16 posted a means of extracting Anhydrous AlCl3 from an (aq) solution by using DMSO
which would precipitate as a complex with the AlCl3 and would release under mild heating, anhydrous AlCl3. I once started to attempt the procedure
however the complete disdain I have for the smell of heated DMSO prevented me from going any further.
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Lambda-Eyde
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Quote: Originally posted by Sedit  | | Over at The Vespiary some time back a member I believe it was V16 posted a means of extracting Anhydrous AlCl3 from an (aq) solution by using DMSO
which would precipitate as a complex with the AlCl3 and would release under mild heating, anhydrous AlCl3. I once started to attempt the procedure
however the complete disdain I have for the smell of heated DMSO prevented me from going any further. |
For those interested in the procedure, see the attached reference.
Attachment: 3471250 PREPARATION OF ANHYDROUS INORGANIC METAL HALIDES.pdf (127kB)
This file has been downloaded 1863 times
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smaerd
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If no one else has confirmed that this works I will conduct tests replacing ethanol with methanol in the very near future.
[Edited on 24-10-2011 by smaerd]
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Vogelzang
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Here's an interesting AlCl3 synthesis. I wonder if it would work with tetrachloroethylene (dry cleaning fluid). It looks like it could be scaled up.
http://www.sciencemadness.org/scipics/AlCl3prep1.gif
http://www.sciencemadness.org/scipics/AlCl3prep2.gif
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Vogelzang
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Aluminum and bromine can react at room temperature. How about making and using aluminum tribromide in place of the trichloride?
http://en.wikipedia.org/wiki/Aluminium_bromide
http://pubs.acs.org/doi/abs/10.1021/j150498a017
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Adas
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Thanks, guys. But I think that dissociation is not a problem. So, what do you think? How pure is Al foil? 98% Al?
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Sedit
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I ran simple test a while back on the feasibility of this reaction and IIRC someone either here or over at The vespiary again attempted this without
very good results. I see no reason to use Tetrachloroethylene when the Dichloromethane they use is so available.
My results showed that when the DCM contained Cl2 it would be yellow... Placing Al into this solution did next to nothing and the yellow persisted
overnight, however when a small amount of amalgumated Al was used the yellow color quickly faded.
See the problem with the solvent synthesis of AlCl3 seems to be that AlCl3 is needed as a catalyst for the reaction. This problem CAN be avoided using
a small amount of Hg to get the ball rolling. I hope someone can make it work but I have yet to hear great results from the solvent methods of
generating AlCl3.
If you fear Hg then perhaps Iodine would work to get things going.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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SHADYCHASE54
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I was just wondering if refluxing aluminium chloride hydrate with a chlorinating agent like thionyl chloride would dehydrate it into an anhydrous
state? If SOCl2 converts carboxylic acids to their respective chloride wouln't the same hold true in this case?
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Adas
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| Quote: Originally posted by SHADYCHASE54 | | I was just wondering if refluxing aluminium chloride hydrate with a chlorinating agent like thionyl chloride would dehydrate it into an anhydrous
state? If SOCl2 converts carboxylic acids to their respective chloride wouln't the same hold true in this case? |
I think it's a good idea. Not impossible.
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thanos thanatos
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| Quote: Originally posted by SHADYCHASE54 | | I was just wondering if refluxing aluminium chloride hydrate with a chlorinating agent like thionyl chloride would dehydrate it into an anhydrous
state? If SOCl2 converts carboxylic acids to their respective chloride wouln't the same hold true in this case? |
Yes, you can use SOCl2 to produce anhydrous AlCl3, but I suspect if someone needs to produce anhydrous AlCl3 because they cannot purchase it (and it
is not a listed chemical), then I think in that case it is even more likely that that same person would not be able to buy thionyl chloride (or PCl3
or PCl5, for that matter), as it is a watched chemical and more expensive than anhydrous AlCl3.
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Nicodem
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| Quote: Originally posted by Sedit | | I ran simple test a while back on the feasibility of this reaction and IIRC someone either here or over at The vespiary again attempted this without
very good results. I see no reason to use Tetrachloroethylene when the Dichloromethane they use is so available. |
Sedit, the referred reaction is something totally different from what you describe. It is apparently an SN1 reaction between
AlI<sub>3</sub> and CH<sub>2</sub>Cl<sub>2</sub>. Its peculiarity is in that the aluminium iodide acts at the same
time as the acid catalyst and as the source of the iodide while dichloromethane acts as a reaction substrate and the solvent.
AlI<sub>3</sub> forms by the oxidation of aluminium with iodine. (This type of nucleophilic substitution on dichloromethane was already
mentioned in the 5th paragraph of this post.)
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radiance88
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I recently just did this experiment because it's probably the easiest to get ahold of materials for and I'm a complete noob at all this. So I placed
Al foil into HCl.. What remained after the considerably vigorous emission of gas (which i assume is Hydrogen), was just metallic looking precipitate,
very similar in color to the aluminum foil.
I assume that this isn't AlCl3? If so... then what was the dark gray precipitate? If there was AlCl3, was it suspended in solution? What exactly am I
looking at in the beaker then?
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Texium
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The gray stuff is excess aluminum, and possibly some impurities in the foil. The aluminum chloride is in solution as hydrated aluminum ions and
chloride ions. If you're going for anhydrous AlCl3 you're barking up the wrong tree, if you just wanted some hydrated AlCl3,
filter and crystallize. Don't boil it down, or it will decompose giving off HCl and leaving you with aluminum hydroxide/oxide.
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Rhodanide
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One great way is to heat Anh. Zinc Chloride with aluminum powder and sort of "Distilling" the subliming AlCl3 into a very cold (and closed) container.
The YouTube channel "Chem Player" has an awesome video on this.
Cheers!
~T
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gdflp
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That method originated from SciMad http://www.sciencemadness.org/talk/viewthread.php?tid=30150#...
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chemplayer...
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It was someone on this site who posted the original blog posting we found. Can't remember which user though. We just kept playing with it until we had
an acceptable yield.
Only caveat is that the product works great for some reactions (e.g. Friedel Crafts acylation it's superb), but for others we're getting substandard
results (vanillin demethylation). It's quite possible there's some subliming ZnCl2 passed over in the product and this has a detrimental effect on
some uses. The reason we suspect this is because we've controlled all variables in some reactions and they're still way below literature yield - the
AlCl3 source is the only thing left to blame.
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blogfast25
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| Quote: Originally posted by chemplayer... | It was someone on this site who posted the original blog posting we found. Can't remember which user though. We just kept playing with it until we had
an acceptable yield.
Only caveat is that the product works great for some reactions (e.g. Friedel Crafts acylation it's superb), but for others we're getting substandard
results (vanillin demethylation). It's quite possible there's some subliming ZnCl2 passed over in the product and this has a detrimental effect on
some uses. The reason we suspect this is because we've controlled all variables in some reactions and they're still way below literature yield - the
AlCl3 source is the only thing left to blame. |
That user was me. I first published it here, then on my blog (where you found it).
Re. your purity point, the only way to 'blame' the AlCl3 conclusively is by comparing it to a commercial grade.
Re-sublimation may be the cure here. I've a feeling that most catalytic grade commercial AlCl3 has been re-sublimated too.
[Edited on 5-5-2016 by blogfast25]
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JJay
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I made some aluminum chloride in a quartz tube by gassing aluminum with hydrogen chloride, but there was still a lot of unreacted aluminum left in it.
I think that putting the aluminum into a boat and gassing with a larger quantity of HCl would have produced better results.
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