Sciencemadness Discussion Board

Anhydrous AlCl3??

sonogashira - 10-9-2006 at 16:10

Hey everyone.
I want to make anhydrous aluminum chloride to use as a catalyst in a reaction i am working on.
I have found a procedure which requires passing dry HCl over heated aluminum powder....

http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/a...

Does anyone have any experience of this? Are there any problems which may occur with this method? Would Cl2 work better than HCl?

I was also wondering whether powdering kitchen foil would be a suitable source for the Al powder.. in other words, how pure is aluminum foil?... do they use some sort of alloy or is it pure enough for this reaction.

Any help will be very much appreciated...

[Edited on 11-9-2006 by sonogashira]

12AX7 - 10-9-2006 at 16:41

Foil is something like 98% pure, the remainder is mostly iron and silicon IIRC.

If you wanted to be sure, you could sublimate the AlCl3 I suppose.

Tim

unionised - 11-9-2006 at 10:46

FeCl3 and SiCl4 are reasonable substitues for AlCl3 in many cases (at least if you are just using it as a catalyst). Purification might be more trouble than it's worth.
Cl2 and HCl both work and they are both nasty to work with. The reaction with HCl gives rise to H2 which complicates things because it's flammable.
What experience do you have with this sort of reaction?

Maja - 11-9-2006 at 11:04

I faced with that kind of problem ,because of AlCl3.. I just bought 100gr of Anhydrous AlCl3 and then made much more myself by bubbling HCl gas thru inert solvent where Al powder was suspended. You need to initiate reaction with small amount of AlCl3, otherwise it won't work. Now I would make small amount of AlCl3 myself. I don't know for what you will use that, but you can substitute it with FeCl3 or SiCl4 as unionised said. Thanks.

sonogashira - 11-9-2006 at 11:06

Do you not think that the product will be reasonably pure? Perhaps if i found a better source of Al than Al foil would that solve the purity concerns?.... Do you see the problem arising from the contaminants in the aluminum or does the process itself lead to an impure product?...
The flammability issue is not a huge concern, i will take suitable precautions.

unionised - 11-9-2006 at 12:41

The product will be pretty pure and the impurities probably won't matter much for most things.

Nick F - 11-9-2006 at 13:01

Does the procedure not involve sublimation itself? If so, that would purify it. I haven't read the procedure, because I'm at a friend's house and he might not want designer-drugs.com on his computer....
But as unionised said, iron and silicon impurities shouldn't matter.
I'd prefer to use HCl than Cl2. Hydrogen isn't a problem to deal with, HCl is a bit less nasty, and it's easier to make anhydrous.

sonogashira - 11-9-2006 at 13:03

Thanks for your help.... Will give it a try and report back.

sonogashira - 11-9-2006 at 13:07

"Does the procedure not involve sublimation itself?"

It basically involves passing a stream of dry HCl over heated Al powder in a tube.

hodges - 11-9-2006 at 13:34

One idea which I have never heard proposed before but seems like it might work would be to react hexachloroethane (C2Cl6, available as a pyrotechnic supply) with aluminum powder in a sealed container. This should be self-sustaining once started; experiment starting with a small amount of reactants on the size of the aluminum particles to get a rate that is not too fast.

You will end up with some carbon as well but might not be a problem; depending on your reaction you could filter it off later.

Hodges

Nicodem - 11-9-2006 at 14:15

Quote:
Originally posted by hodges
One idea which I have never heard proposed before but seems like it might work would be to react hexachloroethane (C2Cl6, available as a pyrotechnic supply) with aluminum powder in a sealed container. This should be self-sustaining once started; experiment starting with a small amount of reactants on the size of the aluminum particles to get a rate that is not too fast.

You will end up with some carbon as well but might not be a problem; depending on your reaction you could filter it off later.

Hodges


https://sciencemadness.org/talk/viewthread.php?tid=1542#pid3...

matei - 16-9-2006 at 14:23

In "Vogel's Practical Organic Chemistry" you can find the procedure for obtaining anhydrous AlCl3 by sublimation. This should be sufficiently dry for catalytic purposes.

sonogashira - 16-9-2006 at 14:44

Thanks a lot matei!!
I have the 5th edition... I had a little look but couldn't find it. Could you give me a page number (or say what section it is under if you have a different edition).. Many thanks for your help!!

ethan_c - 16-9-2006 at 15:41

Quote:
Originally posted by unionised
The product will be pretty pure and the impurities probably won't matter much for most things.


Look at the website he is sourcing from. Although I guess if you're dumb enough to be making drugs either to sell or for your own consumption, impurities are probably the least of your worries.

sonogashira - 16-9-2006 at 15:52

wtf??
Who said anything about making drugs... If you can find another anhydrous AlCl3 synthesis on the internet i would be very interested..
Please don't be so judgemental...

ethan_c - 16-9-2006 at 18:52

Quote:
Originally posted by sonogashira
wtf??
Who said anything about making drugs... If you can find another anhydrous AlCl3 synthesis on the internet i would be very interested..
Please don't be so judgemental...


You're right, a google search did turn that particular procedure up immediately. However, it took 35 seconds fliping pages to find out… that synthesis is copied word for word from Brauer. The internet can be helpful, but I would personally much prefer actual literature to a site like that.

Nicodem - 16-9-2006 at 23:00

Quote:
Originally posted by ethan_c
… that synthesis is copied word for word from Brauer. The internet can be helpful, but I would personally much prefer actual literature to a site like that.

All Rhodium pages have references to where the procedure was taken from and this one is no exception (check the end of the page). Among the hundreds pages, there are only a couple of errors which can be easily spotted by checking the original papers.

So, I do agree that one should take the information from the original literature, but more because there is often some additional information there that can be of use. Otherwise, the Rhodium's archive is pretty much trustworthy for the part that is the transcription from academic literature as well as most (but not all) of the part that originated from amateur experimenters.

I know several friends that work in academic laboratories that sometimes source references and procedures from that incredibly rich archive. Not surprisingly, given that it takes a couple of seconds to check the net when compared to going to the library for a reference search and then looking up for the papers.

PS: What has AlCl3 to do with drugs?

unionised - 17-9-2006 at 11:19

Whether the chemicals he hopes to produce are drugs or not I presume that, at some stage, there would be an isolation procedure that would remove the product from the leftover catalyst. I'd have to think about it to come up with a procedure such that SiCl4 or FeCl3 would be carried into the organic product but AlCl3 would be removed.

sonogashira - 17-9-2006 at 11:53

Any idea how i would do this?.. what common solvents is AlCl3 soluble or insoluble in?
(by the way i am most certainly not making any drugs... i just happened to find that procedure using google.. not my fault if it happens to have "designer drugs" as a webpage!!)

Also, am i right in thinking that AlCl3 can be hydrolysed to Al(OH)3 which would be safe to ingest anyway?

(by the way matei, i am still interested in more info on that vogel reference if you have it... i haven't been able to find it as yet....)

[Edited on 17-9-2006 by sonogashira]

12AX7 - 17-9-2006 at 12:09

Yes, but HCl isn't exactly safe. Plus lots of heat (see also CaCl2 MSDS). You get AlCl3 + 6H2O = AlCl3.6H2O followed by AlCl3 + 3H2O = Al(OH)3 + 3HCl (plus H2O of hydration).

Tim

The_Davster - 17-9-2006 at 12:14

http://www.sciencemadness.org/library/books/vogel_practical_...
;)

sonogashira - 17-9-2006 at 12:59

Thanks a lot rogue chemist thats fantastic!!
Maybe i'm being slow but i cant find the AlCl3 sublimation procedure in this edition either... I've looked in the contents, index, and preparing inorganic solids but still cant find it....

Thanks for the link.. It seems even more useful than the 5th edition for my needs...

matei - 21-9-2006 at 08:04

Sonogashira,

The purification procedure for AlCl3 is in Vogel's 5th Ed. on page 416.
I'm pretty sure AlCl3 is soluble in aromatic hydrocarbons (like benzene or toluene).

sonogashira - 21-9-2006 at 17:02

Many thanks!!

sonogashira - 15-10-2006 at 06:52

Does anyone know what solvents i can use with anhydrous aluminum chloride. i have seen a paper where they used 1,2-dichloroethane; would dichloromethane be ok, or would it react with it? Out of interest does anyone know why it doesn't react with 1,2-dichloroethane?

Maja - 15-10-2006 at 07:21

I think DCM is OK ... I used to use DCM for Anhydrous AlCl3...

sonogashira - 15-10-2006 at 09:42

Thanks maja.. I've actually been able to find a paper which uses a solution of AlCl3 in DCM, but it did also say that it is not very soluble. Don't suppose anyone has (or knows where to get) data on exactly how soluble it is in DCM?

Maja - 15-10-2006 at 10:14

sonogashira, for what purpose you need AlCl3 solution ? What you are going to do ... Not all the time you need to dissolve it ...

sonogashira - 15-10-2006 at 10:41

Just a friedel crafts acylation. Not to make anything in particular, just to give it a try. I can get toluene and acetyl chloride so i was hoping to try this. (note that i dont intend to do it any time in the near future, i appreciate that my chemistry knowledge and experience is very much lacking, so please dont tell me not to bother!!)

I'm just interested in how soluble it is in DCM anyway, not particularly in relation to this reaction, but perhaps for something else in the future. Perhaps you are right and i dont have to dissolve it. i would still be interested as to how soluble it is in DCM, is there some book which lists this kind of data?

The_Davster - 15-10-2006 at 10:46

I have done a few F/C alkyl/acylations at Uni. Dissolving the chloride is unnecessary, just toss it in and the rxn starts very vigorously.

Eclectic - 15-10-2006 at 11:14

I read somewhere that AlCl3 is VERY soluble in diethyl ether. There was even a procedure for purification involving distilling the 1:1 adduct. Now where did I put that reference....

sonogashira - 15-10-2006 at 11:16

Oh right, thats great, so its ok to use an excess of the catalyst? Would there be side reactions if one were to use too much with other reactions (ie not friedel crafts) or can it always be used in excess?

Maja - 15-10-2006 at 11:18

Yes, rogue chemist is right .... I have tried to demethylate vanillin ... You really don't need to dissolve it all .... Stirring helps alot ...