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JJay
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Preparation of Anhydrous Aluminum Chloride from Cupric Chloride and Aluminum
I've been trying to find information on preparing aluminum chloride from copper (II) chloride and aluminum. A couple of reputable sources have stated
that it is possible, but I haven't found many details.
Preparing anhydrous copper (II) chloride is easy enough... it can be made from hydrogen peroxide, hydrochloric acid, and copper metal - or it can be
made from calcium chloride and copper sulfate. Either preparation is easy. I couldn't find any 30% hydrogen peroxide locally, so I used the calcium
chloride / copper sulfate method:
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100.00 grams (0.77519 mol) of calcium chloride monohydrate were added to 200 mL of water and stirred until it dissolved. The solution was allowed to
cool to room temperature, and the specific gravity was measured to ensure that the salt had not been contaminated with additional water. 193.55 g of
copper sulfate pentahydrate was dissolved in 700 mL of water, producing a dark blue solution. The calcium chloride solution was added 10 mL at a time
with stirring. Addition produced a green color that quickly dissipated, along with considerable precipitate. The mixture was allowed to stand
overnight and then vacuum filtered. The clay-like filter cake was washed with 100 mL of water and discarded. The cyan filtrate was found to be
unreactive to additional calcium chloride solution.
The volume of the filtrate was reduced over heat to 400 mL. A small amount of white precipitate formed. The mixture was vacuum filtered, and the
presumed gypsum filter cake was discarded. Reducing the volume to 300 mL did not produce a significant amount of additional precipitate. The solution
was evaporated to dryness in an oven with occasional stirring to produce 85.46 g of an amorphous brown solid, a yield of 82.00%, which was considered
rather low due to mechanical losses.
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So anyway, now I'm looking at around 85 grams of anhydrous copper chloride, and I have a roll of aluminum foil. Anyone have any ideas as to how to
best prepare aluminum chloride from these materials, or should I just start torching assorted stoichiometric compositions in various apparatus and see
what works?
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Amos
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This is something I was thinking about trying at some point, as well. My idea is to stir anhydrous CuCl2 and aluminium powder in chloroform, after
which, theoretically, copper metal or cuprous chloride would settle out and aluminium chloride would be in solution in the chloroform. I have no idea
if it would work, though.
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blogfast25
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Well done on the anh. CuCl2.
The reaction between Al powder and anh. CuCl2 has actually been reported on this forum somewhere (but I can't find it).
I can't vouch for the veracity of the results but as I recall the reaction proceeds but is far too exothermic to be of great use for preparing anh.
AlCl3.
Only one way to find out: try! You will need Al powder though, no matter how course. Foil won't work, I think.
What has been tried and tested (by me) is the preparation of anh. AlCl3 by reaction of Al powder and anh. ZnCl2:
http://oxfordchemserve.com/lab-preparation-of-alcl3-reductio...
This runs nicely contained and at leisurely pace.
It too has been reported here, with one member replicating my results but again I can't find the thread (the search facility is truly crap).
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JJay
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Quote: Originally posted by Amos  | | This is something I was thinking about trying at some point, as well. My idea is to stir anhydrous CuCl2 and aluminium powder in chloroform, after
which, theoretically, copper metal or cuprous chloride would settle out and aluminium chloride would be in solution in the chloroform. I have no idea
if it would work, though. |
It looks like it would take extremely large volumes of chloroform for that to work... I only have about 120 mL, so I don't think I will be able to do
that... but it might be possible to use anhydrous ethanol.
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blogfast25
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| Quote: Originally posted by Amos | | This is something I was thinking about trying at some point, as well. My idea is to stir anhydrous CuCl2 and aluminium powder in chloroform, after
which, theoretically, copper metal or cuprous chloride would settle out and aluminium chloride would be in solution in the chloroform. I have no idea
if it would work, though. |
Worth a shot but I think the reaction is too exothermic, while requiring some temperature to get going.
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JJay
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| Quote: Originally posted by blogfast25 | Well done on the anh. CuCl2.
The reaction between Al powder and anh. CuCl2 has actually been reported on this forum somewhere (but I can't find it).
I can't vouch for the veracity of the results but as I recall the reaction proceeds but is far too exothermic to be of great use for preparing anh.
AlCl3.
Only one way to find out: try! You will need Al powder though, no matter how course. Foil won't work, I think.
What has been tried and tested (by me) is the preparation of anh. AlCl3 by reaction of Al powder and anh. ZnCl2:
http://oxfordchemserve.com/lab-preparation-of-alcl3-reductio...
This runs nicely contained and at leisurely pace.
It too has been reported here, with one member replicating my results but again I can't find the thread (the search facility is truly crap).
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I've seen your work, and I do like the preparation from zinc chloride, but it is just as hard to get zinc chloride here as it is aluminum chloride (I
can get it, but i'd have to pay completely outlandish hazardous material fees).
I have also read that it is possible to prepare zinc chloride from zinc and copper chloride, but I haven't seen the details on that either... might be
interesting to look into at some point in the future.
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Praxichys
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Be careful. Heating mixtures of aluminum and highly halogenated hydrocarbons have been known to cause violent decomposition. Both carbon tetrachloride
and tetrachloroethylene form detonable mixtures with aluminum powder. It has also been documented that aluminum forms an explosive mixture with
chloroform, especially in the presence of AlCl3.
http://webwiser.nlm.nih.gov/getSubstanceData.do?substanceId=...
I don't think it would be too dangerous to try, but definitely make sure the container can vent safely if there is a sudden exothermic reaction. The
product of this reaction is the AlCl3 you're after, so maybe intentionally starting and controlling this reaction is what you need.
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blogfast25
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| Quote: Originally posted by Praxichys | Be careful. Heating mixtures of aluminum and highly halogenated hydrocarbons have been known to cause violent decomposition. Both carbon tetrachloride
and tetrachloroethylene form detonable mixtures with aluminum powder. It has also been documented that aluminum forms an explosive mixture with
chloroform, especially in the presence of AlCl3.
http://webwiser.nlm.nih.gov/getSubstanceData.do?substanceId=...
I don't think it would be too dangerous to try, but definitely make sure the container can vent safely if there is a sudden exothermic reaction. The
product of this reaction is the AlCl3 you're after, so maybe intentionally starting and controlling this reaction is what you need.
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Interesting.
'peach', many moons ago, tried to prepare AlCl3 from Al powder in DCM, gassed with dry HCl. No explosion (but no product either...)
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blogfast25
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The Standard Heat of Formation of CuCl2 is - 206 kJ/mol (NIST), of ZnCl2 it's - 415 kJ/mol (Wolfram Alpha).
That difference of 200 kJ/mol clearly indicates that the reaction with CuCl2 runs MUCH hotter than with ZnCl2.
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gdflp
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Ferric chloride might be another option to consider as well, with an HoF of -400kJ/mol(Wolfram Alpha). It shouldn't be as exothermic as the reaction
with cupric chloride, but it's more widely available(at least in the US) than zinc chloride as it's sold by some pottery suppliers.
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blogfast25
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| Quote: Originally posted by gdflp | | Ferric chloride might be another option to consider as well, with an HoF of -400kJ/mol(Wolfram Alpha). It shouldn't be as exothermic as the reaction
with cupric chloride, but it's more widely available(at least in the US) than zinc chloride as it's sold by some pottery suppliers. |
The fact that FeCl3 sublimes at 315 C could be a recipe for contaminated AlCl3.
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Amos
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| Quote: Originally posted by gdflp | | Ferric chloride might be another option to consider as well, with an HoF of -400kJ/mol(Wolfram Alpha). It shouldn't be as exothermic as the reaction
with cupric chloride, but it's more widely available(at least in the US) than zinc chloride as it's sold by some pottery suppliers. |
Rakugoldpottery on eBay sells anhydrous ZnCl2 as well as FeCl3, both quite cheaply.
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JJay
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It looks like perhaps the easiest way to react CuCl2 with aluminum while capturing the product in an anhydrous state is to dissolve the copper (II)
chloride in dry ethanol and then drip it onto the aluminum. I think aluminum chloride should go into solution with the copper precipitating out. Once
the reaction is complete, the reaction mixture could be filtered and the aluminum chloride precipitated out of the ethanol with chloroform. Right?
[Edited on 16-12-2015 by JJay]
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blogfast25
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| Quote: Originally posted by JJay | It looks like perhaps the easiest way to react CuCl2 with aluminum while capturing the product in an anhydrous state is to dissolve the copper (II)
chloride in dry ethanol and then drip it onto the aluminum. I think aluminum chloride should go into solution with the copper precipitating out. Once
the reaction is complete, the reaction mixture could be filtered and the aluminum chloride precipitated out of the ethanol with chloroform. Right?
[Edited on 16-12-2015 by JJay] |
I'm wondering, just wondering, if AlCl3 with ethanol will not perhaps give Al ethoxide? Or at least partly? Hmmm...
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MolecularWorld
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@OP: Good job!
We all know what the product is, and that it's purity is acceptable for the intended use, but my experience requires me to ask the following pedantic
questions:
How do you know the CuCl2 is anhydrous? What tests did you perform to prove this? Did you test for decomposition after heating? You didn't even state
the temperature or the length of time spent in the "oven".
You mention sourcing reagents locally. I interpret that to mean your reagents are OTC. Everybody knows that all OTC products are highly contaminated,
enough to throw off the results of most experiments (I didn't think so, but I was wrong). You must repeat the experiment with reagent grade chemicals,
and/or verify the product spectroscopically, to ensure contaminants didn't give a misleading result.
What was the purity of the product? How did you determine this?
How do you know your product is anhydrous copper(II) chloride? Don't tell me you judged this based mostly on color, that would be "beneath contempt."
Edit: Also, those one-piece plastic mason jar lids are far from air-tight (I also use them for chemical storage). You'd be better off using a regular
gasketed lid, otherwise your "anhydrous" product soon won't be (unless you store the jar in a desiccator).
"Talk about an aversion to evidence..."
[Edited on 16-12-2015 by MolecularWorld]
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blogfast25
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| Quote: Originally posted by MolecularWorld | | Everybody knows that all OTC products are highly contaminated, enough to throw off the results of most experiments (I didn't think so, but I was
wrong). |
Two broad, sweeping statements and as such inaccurate. There are plenty reasonably pure OTC chemicals and plenty of reactions that are quite robustly
resistant to contaminants.
Your attempt at creating some equivalence here is pathetic, as anyone who has ever prepared anh. CuCl2 will know.
Asking questions isn't pedantic, doing so out of spite though is silly.
[Edited on 16-12-2015 by blogfast25]
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MolecularWorld
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| Quote: Originally posted by blogfast25 | | There are plenty reasonably pure OTC chemicals and plenty of reactions that are quite robustly resistant to contaminants. |
You see, that's what I thought, and to some extant continue to believe; i'll be sure to quote this post the next time someone tries to convince me
otherwise.
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blogfast25
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| Quote: Originally posted by MolecularWorld |
You see, that's what I thought, and to some extant continue to believe; i'll be sure to quote this post the next time someone tries to convince me
otherwise. |
The only way to deal with purity of chemicals, OTC or otherwise, is on a case-by-case basis and in the correct context.
[Edited on 16-12-2015 by blogfast25]
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MolecularWorld
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| Quote: Originally posted by blogfast25 | Your attempt at creating some equivalence here is pathetic, as anyone who has ever prepared anh. CuCl2 will know.
Asking questions isn't pedantic, doing so out of spite though is silly. |
My questions are genuine, though pedantic, and not purely "out of spite".
But I would never have asked them without my previous experience, which was silly indeed.
[Edited on 16-12-2015 by MolecularWorld]
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Detonationology
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| Quote: Originally posted by blogfast25 | | The only way to deal with purity of chemicals, OTC or otherwise, is on a case-by-case basis and in the correct context. |
MSDS sheets are terribly unreliable when it comes to OTC chemicals. The listed range of a chemical concentration in a product always seems to fall on
the lower end. In the case of household ammonia labeled on the MSDS as 3-10% NH4OH, titration found that the concentration was between only 3-3.5%
concentration. It's false marketing! If the MSDS says 99-100%, I could only assume that that would mean that the only other "1%" of ingredients
would be unintentional contamination, and relatively negligible, but it's probably more like 5% contamination, which would be considered quite
significant.
[Edited on 12-16-2015 by Detonationology]
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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blogfast25
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| Quote: Originally posted by Detonationology |
MSDS sheets are terribly unreliable when it comes to OTC chemicals. The listed range of a chemical concentration in a product always seems to fall on
the lower end. In the case of household ammonia labeled on the MSDS as 3-10% NH4OH, titration found that the concentration was between only 3-3.5%
concentration. It's false marketing! If the MSDS says 99-100%, I could only assume that that would mean that the only other "1%" of ingredients
would be unintentional contamination, and relatively negligible, but it's probably more like 5% contamination.
|
MSDS sheets are NOT CoAs or QA statements. They have nothing to do with marketing either.
And last time I looked, 3-3.5 lies within 3-10.
[Edited on 16-12-2015 by blogfast25]
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Detonationology
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If your chemical supplier sold you a chemical that varied in concentration by 7%, would you be happy with your purchase? Would you deem it reliable
enough to use in a reaction where purity is paramount? It's absolutely about marketing: the manufacturer make more money when a higher concentration
is labeled.
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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UC235
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Household ammonia solution is not a reagent and was never meant to be used as one. MSDS is intended to be a statement of hazards about a product for
use by the general public in the event of an emergency. Manufacturers are not required to disclose all ingredients or exact quantities as doing so
would make duplicating their product trivially easy. They are required to list hazardous components and a range of concentrations for which safety
measures are going to be identical. I'm not sure if the numbers they can put for ranges are dictated by law somewhere, but for normal end consumers,
it is irrelevant. If the ammonia cleans their oven fine, then they don't care if it's 3% or 10%.
The ammonia bottle doesn't advertise 10% and then contain 3%. It doesn't advertise any percentage. If it did, the story would be different. If my
8.25% bleach is 6% when I buy it I am not happy. But probably it's going to be 8-9% with the 8.25% being a lowballed estimate to account for
degradation over time.
[Edited on 16-12-2015 by UC235]
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DraconicAcid
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| Quote: Originally posted by Detonationology |
If your chemical supplier sold you a chemical that varied in concentration by 7%, would you be happy with your purchase? Would you deem it reliable
enough to use in a reaction where purity is paramount? It's absolutely about marketing: the manufacturer make more money when a higher concentration
is labeled. |
No, they just don't want to have to print up different MSDSs for their ammonia if they happen to sell 3% and 8% seperately.
Besides- what the MSDS says isn't important for marketing, since that's provided as a safety issue, not a sales pitch. Does it give a concentration
on the bottle?
[Edited on 16-12-2015 by DraconicAcid]
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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blogfast25
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| Quote: Originally posted by Detonationology |
If your chemical supplier sold you a chemical that varied in concentration by 7%, would you be happy with your purchase? Would you deem it reliable
enough to use in a reaction where purity is paramount? It's absolutely about marketing: the manufacturer make more money when a higher concentration
is labeled. |
If it was thus labelled, I'd have no choice or seek out another supplier.
You're conflating purity and concentration. A solution could contain almost only, say, B and solvent and yet B's concentration could be low and
variable. Worksheets can be adjusted for concentration of reagents, usually very easily.
Concentrations of certain chemicals (volatile ones e.g.) may vary inevitably, depending on product. You won't find any HCl 37.50 w% any time
soon.
The marketer is only dishonest if he sells a product that falls outside of the specification as advertised.
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