I prepared solution of salicylic acid in methanol in the work for several times and it always had pink colour. Why? Salicylic acid is colorless.DraconicAcid - 10-11-2019 at 12:13
Iron contamination or oxidation.Steam - 10-11-2019 at 17:20
+1 to draconics recommendation. Might also, be some phenol contamination depending on the purity of the sample and its source. vibbzlab - 10-11-2019 at 17:22
If you can tell how you prepared it maybe we can see where did you get the impurity. Last day I made salicylic acid which was perfectly white in
color from aspirin tablets.Bedlasky - 11-11-2019 at 11:16
I prepared it just by simply dissolving of salicylic acid in methanol.
Salicylic acid was p.a. quality (this means for analysis in CZ). On bottle is list with impurities:
Content: min. 99%
Loss on drying: max. 0,5%
Sulfate ash: max. 0,1%
Chlorides: max. 0,005%
Sulfates: max. 0,02%
Heavy metals (Pb): max. 0,001%
Melting point: 158-161°CBedlasky - 16-11-2019 at 11:10
a picture would help.it could be Iron contamination reacting with salicylic acid (or phenol) and form a complex with ferric ions. it may be taking
time to form because Fe(ii) need air and time to convert Fe(iii) . https://en.wikipedia.org/wiki/Ferric_chloride_test#Chemistry
It takes very little iron to discolor your solution. Iron III salicylate is dark purple even in very dilute solutions, so the pink could be attributed
to nearly trace iron in one of your reagents. Using technical grade MeOH, I have always gotten a purple solution when dissolving salicylic acid. I
remember it being acid and base sensitive, so if you add one or the other and the color goes orange, blue or disappears it should act as a
confirmation. Bedlasky - 17-11-2019 at 13:04
I read on the internet that Fe3+ complex with salicylic acid is blue.rockyit98 - 17-11-2019 at 16:02
I read on the internet that Fe3+ complex with salicylic acid is blue.
why you go to internet for that? just mix some FeCl3 with salicylic acid that you ready got. feeling lazy? rusty nail would do.Sulaiman - 17-11-2019 at 18:02
Salicylic acid is easy to re-crystalise from water
(and makes interesting long hollow square crystals)
so try purification by re-crystalisation to check if the (suspected) iron contamination is in the salicylic acid, or the methanol.
You could also do a quick distillation of your methanol if required.Abromination - 17-11-2019 at 20:04
Heres a pic for you, it is not blue. Iron III salicylate.
Very very dilute solution containing only milligrams of SA and ferric chloride.
[Edited on 11-18-19 by Abromination]Bedlasky - 18-11-2019 at 07:25
Heres a pic for you, it is not blue. Iron III salicylate.
Very very dilute solution containing only milligrams of SA and ferric chloride.[Edited on 11-18-19 by Abromination]
