[doughpat]

Hi everyone--not sure why this lab didn't work out.   Any tips would be appreciated.

Trying to extra salicylic acid from Walgreens aspirin tablets. 

Powdered ~2 grams (5 aspirin tablets), added to a flask, added ~ 50 mL isopropyl alcohol.  Stirred for 10-15 minutes.  Added ~250 mL cold water, then cooled the entire mixture in an ice bath. 

Expected to obtain crystallized salicylic acid.  No crystals observed in any of the trials.

My best guess is that I used too little starting material (aspirin tablets) and that the salicylic acid is sufficiently soluble in the cold water/isopropanol to remain in solution.  Also tried the same procedure using ethanol--same (lack of) results.

I followed this procedure:  http://home.comcast.net/~drewpoche/CHEM3/CHEM_III_labs_files/Extraction%20of%20Acetyl%20Salicylic%20Acid.pdf, which calls for a much larger (~30 tablets) to be used in the same volume of solvent.

[AlphaScent]

There is no salicylic acid in asprin.  There is, however, acetylsalicylic acid.

[doughpat]

Whoops--pardon the error and thanks for spotting it, AlphaScent.

I meant to say we are extracting acetylsalicylic acid from the tablets.  I believe later on in the procedure we will convert it to salicylic acid (using HCl and heat, I believe).

[Arkcon]

OK, you think that using fewer tablets gave you so little acetylsalicylic acid that it stayed in solution.  So prove it.  How much active would have been in 30 tablets and how much was in 5 tablets?  Can you measure and work with the amount in question easily?

[voidSetup]

You scaled down the number of tablets from the procedure. Should you have scaled anything else down?

[doughpat]

Thanks for the help everyone.  I performed the procedure again, but scaled everything down (including solvents).  Seems to be working fine--just need to dry the product and see my % yield.