AWLB - 30-7-2015 at 09:25
The presence phenols and salicylic acid can be tested easily by the addition of iron (III) chloride (FeCl3); they react to form a very bright purple
colored complex. This test is often used industrially to test aspirin (acetylsalicylic acid) for purity because if its derivative, salicylic acid, is
present it will turn purple but if the product is pure no color change will be observed.
Method
1. Dissolve your sample of phenol or salicylic acid in 90 degree celsius water( these compounds are much more soluble in hot than cold water.)
2. Add 1ml of 10% FeCl3 solution.
3. Observe color change.
[Edited on 30-7-2015 by AWLB]
Deathunter88 - 30-7-2015 at 11:19
The same thing may happen when you make methyl salicylate and use impure chemicals. Sure confused the heck out of me the first time.
AWLB - 30-7-2015 at 11:24
Thanks for commenting "Deathhunter88", I have also noticed the same thing when making salicylate esters due to iron (FeCl3) contaminants in my
hydrochloric acid (the catalyst I used).