Sciencemadness Discussion Board

Anhydrous Iron(III) Chloride

gdflp - 10-7-2015 at 07:10

I just placed a small order recently from US Pigment Corp., and one of the chemicals I ordered was a pound of ferric chloride for $7. I was fully expecting this to be the hexahydrate, even though it was listed on the invoice as anhydrous. On arrival however, and to my great surprise, I received anhydrous ferric chloride. I did some qualitative testing to ensure that it was anhydrous and here are the results :

Appearance : Free flowing black powder, quickly absorbs moisture from the humid air and turns yellow, as I found out when I didn't cap one of the bottles tightly enough.

Decomposition : A small amount was placed in a test tube and heated above an alcohol lamp for 20-30 seconds. No changes were observed and, after cooling, it dissolved completely in a small amount of distilled water giving a yellow solution, indicating no decomposition into oxychlorides as would be expected with the hydrated salt.

Once I finish my run of benzene(or I will just use toluene), I will try a Friedel-Crafts Alkylation with this salt and t-butyl chloride as a final test. If successful, this is, in my opinion, a cheap source of a quite useful Lewis acid.

byko3y - 10-7-2015 at 08:34

Selling no AlCl3. Useless supplier.

gdflp - 10-7-2015 at 09:23

Quote: Originally posted by byko3y  
Selling no AlCl3. Useless supplier.

They are a pottery supplier, that's not surprising in the least. Just the fact that they sell anhydrous FeCl3 is surprising to me. Considering that FeCl3 can be substituted for AlCl3 in many reactions, and also has it's own unique reactions, I wouldn't call FeCl3 useless.