Sciencemadness Discussion Board

hygroscopic aluminum chlorohydrate issue

gardul - 10-2-2015 at 17:34

I have a HUGE problem and need all of your help and ideas. Because I am newish to chemistry, I am not 100% confident in handling this situation.

Note: Please by all means correct me if I am wrong in anything I say in this.

From what I gather; Aluminium Chlorohydrate is a hydrated inorganic polymer form of Aluminum Chloride. The two forms I have come across is a Amber gel like substence that can be discribed like an opaque honey. I have also seen it as a yellow powder.

The problem I am having is this is extremely hygroscopic. I know Aluminum Chloride is as well. It seems like no matter what I do, this stuff abosorbs the mostier around. Mind you I like in the Arizona desert. So it pretty dry here. I Have tried layers in a cantainer with drying agents and all sorts of other things. Leaving it outside is a no go. Within 3 days its just a brown liquid.

So, I am wondering, If any of you know of a way to be able to keep this in gel/salt form without it absorbing so much water?

I am at a complete loss here. Any infomation would be awesome. Thanks in advance.

Zombie - 10-2-2015 at 17:38

How about those heavy duty "ZipLok baggies, and a packet or two of Silica Gell?

gardul - 10-2-2015 at 17:47

Tried that. Still absorbs. Its been mind racking.

woelen - 11-2-2015 at 05:56

For some chemicals you just have to accept that once they are wet, they are lost. You could try putting the material in the blazing sun or put it in an oven at 90 C setting, but be prepared that the material can easily decompose, giving a little HCl and a basic salt, which remains behind.

Btw., aluminium chloride is not amber colored, it is colorless or white if finely divided. It contains a lot of impurity if it is amber. It also is not a gel, it is a crystalline solid.

Aluminium chlorohydrate probably is some hydrated basic chloride of aluminium, and this also is colorless or white.

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I myself have even more hygroscopic chemicals than what you describe. Some chemicals are so hygroscopic that they even liquefy in very dry air and cannot be recovered anymore by drying, due to decomposition by loss of acid.

blogfast25 - 11-2-2015 at 07:42

Quote: Originally posted by gardul  

From what I gather; Aluminium Chlorohydrate is a hydrated inorganic polymer form of Aluminum Chloride. The two forms I have come across is a Amber gel like substence that can be discribed like an opaque honey. I have also seen it as a yellow powder.



Did your product come with any documentation? "Aluminium Chlorohydrate" is a fairly vague term that covers a multitude of sins.

gardul - 11-2-2015 at 17:33

Quote: Originally posted by woelen  
For some chemicals you just have to accept that once they are wet, they are lost. You could try putting the material in the blazing sun or put it in an oven at 90 C setting, but be prepared that the material can easily decompose, giving a little HCl and a basic salt, which remains behind.

Btw., aluminium chloride is not amber colored, it is colorless or white if finely divided. It contains a lot of impurity if it is amber. It also is not a gel, it is a crystalline solid.

Aluminium chlorohydrate probably is some hydrated basic chloride of aluminium, and this also is colorless or white.

----------------------------------------------------------

I myself have even more hygroscopic chemicals than what you describe. Some chemicals are so hygroscopic that they even liquefy in very dry air and cannot be recovered anymore by drying, due to decomposition by loss of acid.




UPDATE: THANK YOU WOELEN!

I got a small little toaster oven cheap at the store. I'm sure some of it did decompose to an Oxide (or at least i would assume. Correct me if I am wrong.)

Now what I find odd here is, my 30% "pure" HCl turned this product the amber color.

my 29 % unpure HCl that I got at the local hardwarestore turned the product an off white. Which is rather normal for this stuff normally a recyrstalization works to get a better product.

So My conclusion for this is that I personally screwed up some where. This has to be the reason why my orginal batch became yellow.

What I have also discovered, is that the PH level differs from What I see being sold online. Mine is 1 for the "pure" HCl and 3 for then unpure HCl. The PH i see being sold ; I am told is 3-5. This leaves me with the conclusion that not all the HCl is actually being consumed.

I will be attempting again this weekend and see what I get.







[Edited on 12-2-2015 by gardul]

woelen - 12-2-2015 at 00:08

If you used clean glass equipment in your experiments, then pure HCl certainly should not turn your product amber. However, I have seen similar things with some of my experiments. I have some ZnCl2 which is white. If I dissolve this in water I get a very pale brown solution, if I dissolve this in excess amount of a pure solution of NaOH, then I get a yellow/brown solution. Apparently, something in the ZnCl2 is decomposed to a brown compound when it becomes alkaline. In your situation you may have that in your starting product there is an impurity, which turns brown in strong acid. Anyway, there is some impurity involved.

What I did myself is distilling hardware store 30% HCl. I diluted part of my acid, so that it becomes roughly 20% HCl by weight and then I distilled this liquid until appr. 10% of the voume remains. This yields very nice colorless 20+ % HCl. Then I took my remaining conc. HCl and distilled this, with the gas and liquid from this leading into the other pure 20% HCl. First, mainly HCl gas comes over, which dissolves in the HCl and then 20% HCl comes over.

The last 10% or so of liquid was piss-colored and I discarded that, I stopped distilling well before I had a dry mass. In this way, I made 250 ml of appr. 25% HCl which is absolutely free of colored impurities and certainly does not contain any metal ions (e.g. iron, which is common in impure HCl).

You need all glass apparatus, I used a small NS19 distillation set with ground glass joints and a heating mantle.

gardul - 12-2-2015 at 00:37

Should I use a Vigreux Column?

woelen - 12-2-2015 at 02:08

You can use one, but there is no real need for that.

AJKOER - 15-2-2015 at 16:53

Quote: Originally posted by gardul  
I have a HUGE problem and need all of your help and ideas. Because I am newish to chemistry, I am not 100% confident in handling this situation.

Note: Please by all means correct me if I am wrong in anything I say in this.

From what I gather; Aluminium Chlorohydrate is a hydrated inorganic polymer form of Aluminum Chloride. The two forms I have come across is a Amber gel like substence that can be discribed like an opaque honey. I have also seen it as a yellow powder.

The problem I am having is this is extremely hygroscopic. I know Aluminum Chloride is as well. It seems like no matter what I do, this stuff abosorbs the mostier around. Mind you I like in the Arizona desert. So it pretty dry here. I Have tried layers in a cantainer with drying agents and all sorts of other things. Leaving it outside is a no go. Within 3 days its just a brown liquid.

So, I am wondering, If any of you know of a way to be able to keep this in gel/salt form without it absorbing so much water?

I am at a complete loss here. Any infomation would be awesome. Thanks in advance.


Does this comment from Atomistry.com on AlCl3 give you any worthwhile ideas (link: http://aluminium.atomistry.com/aluminium_trichloride.html )?

"The compound AlCl3.NaCl was formerly manufactured for use in the preparation of aluminium. It is not so hygroscopic as aluminium chloride, melts at 185°, and volatilises at a red heat. The compounds AlCl3.KCl and AlCl3.NH4Cl are similar. "

[Edited on 16-2-2015 by AJKOER]

blogfast25 - 15-2-2015 at 17:08

Quote: Originally posted by AJKOER  
Does this comment blahdiblah


What do the chloroaluminates have anything to do with anything here?

[Edited on 16-2-2015 by blogfast25]

AJKOER - 15-2-2015 at 17:19

Blogfast, glad your around.

The conjecture is perhaps think of replacing the AlCl3, per my quoted reference, with the basic aluminum salt of interest.

The problem then becomes to construct a double salt with hopefully a reduced affinity for water that still meets ones needs (meaning other than simply displaying the pure salt of interest, which one may be able to address by immediately sealing in a glass tube).

He did ask for ideas.

[Edited on 16-2-2015 by AJKOER]

blogfast25 - 15-2-2015 at 18:10

Quote: Originally posted by AJKOER  
Blogfast, glad your around.

The conjecture is perhaps think of replacing the AlCl3, per my quoted reference, with the basic aluminum salt of interest.

The problem then becomes to construct a double salt with hopefully a reduced affinity for water that still meets ones needs (meaning other than simply displaying the pure salt of interest, which one may be able to address by immediately sealing in a glass tube).

He did ask for ideas.

[Edited on 16-2-2015 by AJKOER]


Trust me, chloroaluminates don't suffer water well. Find a thread where I tried to synth KAlCl4 with aqueous chemistry: a TOTAL waste of time.

gardul - 25-2-2015 at 00:14

quick update... SUCCESS!!. kinda... I am not sure if i have poly aluminum chloride or aluminium chlorohydrate. But it works as planned. I will have pictures soon i hope. Will also do a write up.

Here was the idea. I set out to make a water flocculant that could be made from materials laying around the house, or in case in time of need where water supplies may not be the greatest.

At first I couldn't get it to dry past a gel state. Woelen Suggested a toaster oven. And it worked perfectly.

I also didn't realize how bad the PH would drop. My distilled water has a PH of just above 7. when this substence was mixed it dropped between 3-5. To counter this, I added sodium bicarbonate and sodium chloride. The PH jumped to 9 but then settling back down to 7.

I also tested this with no water at all.. I was amazed in what I saw. Since I had always thought water played a roll, but from what I saw it doesnt.

I would like to first mention that my aluminum chlorohydrate is an off white color due to impurties.

But as I mixed the dry chemicals. they instantly started to react. A hissing and crackling sound was heard. The Aluminum cholohydrate and the sodium chloride bonded togather. the sodium carbonate was kinda just stuck in the middle. There was also a color change. Off white to pure white.

I also got a cyrstal out of this...

Now I do understand how this all works.. but I was led to believe that H2O had some part in the flocculant process. ( sorry if this doesn't make sense I am rather tried)

The dry finial product doesnt react with water that I can tell.