Sciencemadness Discussion Board

AlCl3 from HCl and foil

zenmanenergy - 4-3-2018 at 20:58

I am attempting to make some aluminum chloride to intercalate into graphite to make a p-type ink for a thermal electric generator.

Anyway, my plan is to mix aluminum foil with muriatic acid. Using:

6 HCl + 2 Al = 2 AlCl3 + 3 H2

I'm not 100% sure, but from a bit of googling, I found that muriatic acid is about 10M concentration. Is that a reasonable assumption to work with?

The videos I've seen doing this seem to produce a grey distillate. Although when I purchased some aluminum chloride hexahydrate, they were white crystals. I'm assuming the grey color is from impurities. Will acetone help remove some of these impurities?

With this process ultimately produce a hexahydrate AlCl3? If so, how do you make an anhydrous version?

VSEPR_VOID - 4-3-2018 at 21:15

The concentration of the acid does not matter in your application. If you are looking to make a specific amount of aluminium chloride then use a corresponding amount of aluminium. One mole of aluminium yields one mole of the chloride salt.

An Example

26.98 grams of aluminium when fully reacted with hydrochloric acid (muriatic acid) will yield 241.432 grams of aluminium chloride hexahydrate. This can be dehydrated to anhydrous aluminium chloride by heating it to 100 C for some time. As a side note aluminium foil is a expensive source of the metal. Consider using cans, with the labels removed, instead.

If your final product is yellow that is due to contamination from your acid, and if it is grey from your aluminium. Acetone will not help remove the impurities. If you wish to purify your product I recommend recrystallizing it in either ethyl alcohol or pure water.

RogueRose - 4-3-2018 at 21:26

I've seen a solution that was very dark grey to blackish and this material was removed by a good filter. If all the color doesn't come out the first pass through, run it through another time or two, the particles in the filter will build up and it will eventually filter the smallest particles. I found the AlCl3 particularly difficult to filter the first 2 passes but then the third it was crystal clear. The thing is that you use the same filter for all filterings, each one wil probably take longer, so sit back and let it drip slowly over the day (or 2)

UC235 - 4-3-2018 at 21:37

Quote: Originally posted by VSEPR_VOID  
This can be dehydrated to anhydrous aluminium chloride by heating it to 100 C for some time.


No it absolutely cannot. You will produce Al2O3 or possibly some oxychlorides. Anhydrous AlCl3 has to be produced from Al and HCl or Cl2 in the absence of water. The reaction with Cl2 is violently exothermic but can be moderated by a solvent (though most also react). It is much cheaper and easier to buy some.

Magpie - 4-3-2018 at 21:38

I assume you need anhydrous AlCl3. This is hard to make due to its strong propensity to take on water. The only time I’ve seen this made is by blogfast25. He reported this with pictures but I can’t find his report.

ninhydric1 - 4-3-2018 at 22:04

Couldn't you generate HCl from bisulfate + NaCl, dry it through CaCl2 or H2SO4, the lead it to Al foil/ powder? You would need to etch the Al2O3 somehow though, maybe a bit of H2SO4 or another anhydrous acid.

VSEPR_VOID - 5-3-2018 at 01:17

Quote: Originally posted by UC235  
Quote: Originally posted by VSEPR_VOID  
This can be dehydrated to anhydrous aluminium chloride by heating it to 100 C for some time.


No it absolutely cannot. You will produce Al2O3 or possibly some oxychlorides. Anhydrous AlCl3 has to be produced from Al and HCl or Cl2 in the absence of water. The reaction with Cl2 is violently exothermic but can be moderated by a solvent (though most also react). It is much cheaper and easier to buy some.


My mistake. I misread the article on AlCl3

clearly_not_atara - 5-3-2018 at 03:18

Somehow I imagine you could make AlCl3 by grinding Al with anhydrous cupric chloride, but I'm honestly guessing.

Texium (zts16) - 5-3-2018 at 05:42

Or possibly by adding aluminum to a solution of anhydrous cupric chloride in dry methanol or ethanol. The anhydrous CuCl2 and AlCl3 are both very soluble according to Wikipedia, though I've never tried such a displacement myself.

JJay - 5-3-2018 at 06:07

I made some aluminum chloride in a quartz tube with hydrogen chloride, but I didn't get extremely high purity due to various factors (mainly inexperience I think). It's pretty easy to do. I'm quite sure I could do it much more effectively with my current equipment and skillset.

Cupric chloride forms a thermite with aluminum that produces aluminum chloride smoke. I found that the thermite burns pretty hot, but Polverone mentioned on the exotic thermites thread an experiment where he wrapped cupric chloride with aluminum foil and burned it without the reaction becoming super vigorous.

If you could somehow react cupric chloride with aluminum in a suitable vessel and lead the smoke into a glass chimney (perhaps constructed from a water-cooled condenser), I think you could capture useful amounts of reasonably pure aluminum chloride.

Reacting cupric chloride and aluminum in a partially-closed container is a pretty dangerous experiment, though, and the only way I could think of to do it at all safely would be to have the apparatus held together by gravity so that unexpected high pressures merely lift the lid rather than building up and causing an explosion. I have not read any reports of anyone making useful amounts of aluminum chloride that way, but I think it is possible. It's probably easier to just use hydrogen chloride and a tube furnace, though.

Rhodanide - 5-3-2018 at 06:31

I know that ChemPlayer has a great video on making anhydrous AlCl3, by the rather clever route of heating anhydrous ZnCl2 and Al powder, and "distilling" the AlCl3 off as a nice white powder. I can give a link to the video, they did a great job IMO.
3 ZnCl2 + 2 Al -> 2 AlCl3 + 2 Zn
:)


Link to ChemPlayer's video: https://www.youtube.com/watch?v=g7sS69fQMsk


[Edited on 3-5-2018 by Rhodanide]

JJay - 5-3-2018 at 06:53

That is probably the easiest way to make AlCl3. The only major drawback to it is that ZnCl2 is hard to find OTC... supposedly it is used as a welding flux, but I never found any.

clearly_not_atara - 5-3-2018 at 07:24

ZnCl2 cannot be dried by heat. CuCl2 can if you have good temperature control. InCl3 can as well IIRC if you have access to indium. I see I underestimated the reaction energy.

I don't know if AlCl3 can be obtained from methanolic solution. You might get methyl chloride. I believe CuCl2 is soluble in acetone, though. GAA might also be a good solvent choice.

[Edited on 5-3-2018 by clearly_not_atara]

zenmanenergy - 5-3-2018 at 08:41

Holy crap.

I posted this last night and you all have posted 12 responses by lunchtime!!!

THIS FORUM IS AWESOME!! :o

I'm going to go out back and give this a try, I suspect I'll end up just buying some anhydrous AlCl3. But I'd like to try this reaction just to see it in action.

I tried the graphite intercalation twice with hydrous AlCl3, once using the modified hummers method then other using the heat pipe method with FeCl3 as the catalyst. Neither came out the way Robert Murray Smith's did and I'm pretty sure the added H2O was the reason. Have any of you tried intercalating AlCl3 with graphite?

[Edited on 5-3-2018 by zenmanenergy]

zenmanenergy - 5-3-2018 at 08:46

Quote: Originally posted by UC235  
Quote: Originally posted by VSEPR_VOID  
This can be dehydrated to anhydrous aluminium chloride by heating it to 100 C for some time.


No it absolutely cannot. You will produce Al2O3 or possibly some oxychlorides. Anhydrous AlCl3 has to be produced from Al and HCl or Cl2 in the absence of water. The reaction with Cl2 is violently exothermic but can be moderated by a solvent (though most also react). It is much cheaper and easier to buy some.


I can attest to this... I had a bottle of hydrous AlCl3. I was curious if I could dehydrate the H2O by heating it. I weighed out 5.04g of AlCl3+6H2O dissolved it into 50ml of DI water. Then boiled all the water off until I was left with nothing but salt and weighed to salt... I still had 5 grams of salt.

zenmanenergy - 5-3-2018 at 08:50

Quote: Originally posted by Magpie  
I assume you need anhydrous AlCl3. This is hard to make due to its strong propensity to take on water. The only time I’ve seen this made is by blogfast25. He reported this with pictures but I can’t find his report.


Robert Murray Smith uses anhydrous AlCl3 in his graphite intercalation process. I asked him whether the hydrous salt could be used, but he was pretty vague with his answer. I didn't want to annoy him asking for more details because I like asking him questions occasionally.

I've tried the intercalation process twice now with hydrous AlCl3 and I'm not convinced it is working. I possible I messed up the reactions, but I think the H2Os are a problems.

Looks like you all are in agreement that this HCL+foil will make hydrous AlCl3, which is fine. I'll try it anyway, for fun, then probably just order a bottle of professionally made AlCl3 :-)

happyfooddance - 5-3-2018 at 09:46

The hydrated salt CAN be dried. It is about as unwieldy as the tube furnace, dry HCl method though, so unless you have a HCl canister... Maybe just buy it. You can't dry it with heat or a dessicator.

The method is something like this: AlCl3 hydrates are placed in a flask with a solvent (DCM? Not sure...) which is brought to reflux, while a stream of dry HCl is passed through the mixture. Depending on quanties this is continued for up to 48 hours.

Easier just to buy it.

zenmanenergy - 5-3-2018 at 11:02

Quote: Originally posted by happyfooddance  
Easier just to buy it.


Agreed. I just made a little batch. Now I know the process. I think it was successful, but it didn't make very much at all. I certainly looks black to me, not white crystals like I was expecting.

Where do you guys buy your chemicals from? I tried placing an order from alfa.com, but they rejected it since I was shipping to my house. I may have to send stuff to my friend at a University here in Norfolk, but I'd rather just find a place that will ship directly to me.

Bert - 5-3-2018 at 12:00



You're in VA? So is Chemsavers, as I recall.

https://www.chemsavers.com

Member Tomholm here is Elemental Scientific/BME Lab and Science

https://www.sciencemadness.org/whisper/viewthread.php?tid=74...

https://www.elementalscientific.net/store/scripts/prodList.a...

happyfooddance - 5-3-2018 at 13:10

Quote: Originally posted by zenmanenergy  


Agreed. I just made a little batch. Now I know the process. I think it was successful, but it didn't make very much at all. I certainly looks black to me, not white crystals like I was expecting.


To me, this doesn't sound like you "now know" the process. It doesn't sound even like you made a little batch. Almost guaranteed, you made a small batch of something which was NOT your target chemical...

To be fair to those who have made this chemical...

zenmanenergy - 5-3-2018 at 13:34

Quote: Originally posted by happyfooddance  


To me, this doesn't sound like you "now know" the process. It doesn't sound even like you made a little batch. Almost guaranteed, you made a small batch of something which was NOT your target chemical...

To be fair to those who have made this chemical...


Fair enough. Is there a technical difference between little and small?

I just did a second batch, still very small (or little?) but this time 20g of aluminum instead of 5g. I was just trying to keep my 1L beaker from overflowing and making a mess.

I'm still in the process of washing it, but it visibly appears to have worked. Are you suggesting I am missing a bunch of steps? I plan on ultimately buying a high quality salt, but I do want to understand this process. If you have any suggestions, I'm all ears.

happyfooddance - 5-3-2018 at 15:38

Quote: Originally posted by zenmanenergy  
Is there a technical difference between little and small?

I just did a second batch, still very small (or little?) but this time 20g of aluminum instead of 5g. I was just trying to keep my 1L beaker from overflowing and making a mess.



Technically, the difference would be between micro and macro, in my opinion. Chemically, I think the difference would be between some and none, in the case of your experiment. I could be being harsh, but I have made this compound.

[Edited on 3-5-2018 by happyfooddance]

zenmanenergy - 5-3-2018 at 16:51

Quote: Originally posted by happyfooddance  

Technically, the difference would be between micro and macro, in my opinion. Chemically, I think the difference would be between some and none, in the case of your experiment. I could be being harsh, but I have made this compound.

[Edited on 3-5-2018 by happyfooddance]


It is no doubt on the micro scale! There is definitely a little pile of *something* there. How much, if any, is Aluminum chloride I don't know yet. I'm going to try and wash it a couple times tomorrow.

When you've made it in the past, did you use HCl or some other technique?

Magpie - 5-3-2018 at 16:57

I recommend studying this thread:
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...

"Preparation of Anhydrous Aluminum Chloride."

I have never made AlCl3. I buy it from Elemental Scientific, LLC.

happyfooddance - 5-3-2018 at 17:06

Quote: Originally posted by zenmanenergy  
Quote: Originally posted by happyfooddance  

Technically, the difference would be between micro and macro, in my opinion. Chemically, I think the difference would be between some and none, in the case of your experiment. I could be being harsh, but I have made this compound.

[Edited on 3-5-2018 by happyfooddance]


It is no doubt on the micro scale! There is definitely a little pile of *something* there. How much, if any, is Aluminum chloride I don't know yet. I'm going to try and wash it a couple times tomorrow.

When you've made it in the past, did you use HCl or some other technique?


Dry HCl. It takes a lot of heat to initiate. If this is your first time messing with hot, dry HCl, I strongly suggest you find another project to play around with, first. Hydrogen exits this set-up, at a concentration that will happily explode. But more importantly, HCl is not really the sort of thing anybody should be playing around with.

I would gladly sell you AlCl3, just to not see you maim yourself. There are others who I am sure would give you a better price.

Even hot HCl gas can cause an explosion.

Texium (zts16) - 5-3-2018 at 18:33

I ran a quick qualitative experiment to test out the possibility of making AlCl3 in methanol. Freshly dried anhydrous CuCl2 was dissolved in dry methanol (dried over anhydrous MgSO4). A crumpled piece of aluminum foil was added to the solution (left). To compare, some of the same CuCl2 was added to another beaker containing water (right), and a piece of aluminum foil was added to it as well. Effervescence was observed in the methanol solution. After a few minutes without much happening, a small grain of iodine was added to each beaker. This did not appear to change anything- a slight increase in the rate of effervescence at best.

Displaced copper metal was observed in both solutions, but was evolved more rapidly in the aqueous solution. Effervescence was observed in both solutions but occurred at a much faster rate in the methanolic solution.

Methanol-CuCl2.JPG - 1.1MB

I don't think that these conditions will work for producing AlCl3, but it is difficult to determine what is actually happening here. Aluminum methoxide forming in situ?

clearly_not_atara - 5-3-2018 at 20:32

Copper is known to activate aluminium (usually CuSO4) so the methoxide seems like a strong possibility.

Iodine reacts rapidly with methanol and cannot be used to activate aluminium in methanol. Formaldehyde is produced. Solvents compatible with I2 include acetonitrile, propylene carbonate, tert-butanol (maybe) and DMF. Acetone will surely be oxidized; DMSO might be oxidized.

DraconicAcid - 5-3-2018 at 20:45

Iodine reacts rapidly with methanol? I don't think so- I've run labs where the students react iodine with zinc in dry methanol to determine the product of the reaction.

clearly_not_atara - 5-3-2018 at 21:22

Really? I suppose I was wrong. I2 has come up for alcohol oxidations before, can't remember why.

DraconicAcid - 5-3-2018 at 21:31

In basic solution, iodine will oxidize things like isopropanol to give acetone, and then follow up with the iodoform reaction, but we've boiled zinc and iodine in methanol for extended periods without the methanol obviously reacting.

Texium (zts16) - 6-3-2018 at 06:52

Not to mention using iodine and phosphorus (or aluminum!) in methanol or ethanol to make the corresponding iodides. It's pretty well accepted that iodine does not oxidize methanol to formaldehyde.

[Edited on 3-6-2018 by Texium (zts16)]

Texium (zts16) - 6-3-2018 at 08:52

Oh, and last night after about an hour, the aluminum fully reacted with the methanolic CuCl2 (solution was colorless, copper metal and excess aluminum was present). The aqueous solution took much less time to react.

I decided to test the methanolic solution by adding a few drops to a test tube with some water. It didn't visibly react, but the mixing was noticeably exothermic. It seems most likely that there is dissolved aluminum methoxide present, as there wasn't any HCl gas formed as far as I could tell. In retrospect I suppose I should have checked the pH, but I wasn't really thinking.

DraconicAcid - 6-3-2018 at 08:59

Why would you even consider the formation of methoxide? The expected product would be aluminum chloride, solvated with methanol.

Texium (zts16) - 6-3-2018 at 09:11

Do you know for a fact that aluminum chloride doesn't react with methanol? I couldn't find anything saying explicitly that it does or doesn't, but I also saw that aluminum chloride generally reacts with alcohols to give alkoxides: https://www.masterorganicchemistry.com/2011/07/22/reagent-fr... (Yeah, I know it's a homework-helping site so take it for what it's worth)

And while looking around I also saw this patent: https://patents.google.com/patent/US3083218

DraconicAcid - 6-3-2018 at 11:21

I would expect the equilibrium of AlCl3 + 3 ROH = Al(OR)3 + 3 HCl to lie to the left, because methoxide is a really strong base (even when coordinated to aluminum) and HCl is a really strong acid. If you were to boil off the HCl, you might get the methoxide, but I'd guess you'd be more likely to get a crappy mix of oxide, hydroxide, methoxide and basic chloride.