Sciencemadness Discussion Board

Salsalate question

Arbacluce - 18-10-2015 at 14:13

Hi

I wanted to make phenol by decarboxylation of salicylic acid http://www.sciencemadness.org/talk/viewthread.php?tid=27617

Acid melted and it started bubbling but in destilatin flask there was no crystals of phenol, only colorless liquid but temperature was 25C i thought that is supercooled phenol but after shaking, it didn't want to crystallize. Smell of this dense oil is nice, and reaction mixture that i poured into cold water also didn't crystallize but form orange/brown oil that sink to the bottom. Is this Salsalate?

[Edited on 18-10-2015 by Arbacluce]

UC235 - 18-10-2015 at 14:54

Did you redistill the product to remove water and salicylic acid that was carried over? A small amount of water is sufficient to depress phenol's melting point such that it remains liquid at room temperature since it only melts at 41C when very pure.

Salsalate is a crystalline solid melting at 137C. I guarantee you didn't distill any though it may form as an intermediate in the decarboxylation. Orange/Brown would indicate phenol oxidation products.

Arbacluce - 18-10-2015 at 14:59

No. I didn't redistill it., you are right :).

UC235 - 18-10-2015 at 15:16

Quote: Originally posted by Arbacluce  
No. I didn't redistill it., you are right :).


If you didn't throw it out, you can steam distill to recover the phenol (phenol dissolves to about 8% in water so a lot of it will not be in the lower organic phase). Saturate the distillate with salt and extract several times with dichloromethane, ether, or ethyl acetate. Dry with Magnesium sulfate (CaCl2 will react, probably), and strip the solvent.