I have a question about compounds that oil out of solvents after drying.
How would I analyze this? Could I make a KBr pellet, or would I just be able to analyze it in UV spec?
I assume that the solvents used to dissolve the compound, would be used as a blank, right?
I tried to dry off the solvent used to dissolve the compound and it wouldn't completely dry off, and this is why I think it was oiling out of solution. I was originally planning on trying extraction after drying off the compound. I had no choice but to try to go and re-dissolve the compound in a solvent (CH2Cl2). It looked like it dissolved, but I'm not sure since the pasteur pipette looked as if it had an oily residue after I pipetted the solution over to another container....
Not sure what to do now,
Thank you
2 answers
I have no idea what "oiling out of solution" means. Sure you can make a KBr pellet. AND you can run the sample on a UV. Can it be that part of the unknown dissolved in CH2Cl2 and the "oil part" was another compound? If I thought some had dissolved in CH2Cl2, I would attempt to recover the part that dissolved. That could be a pure component.
I dried a solution of solvent + unknown compound dissolved in it, and it would not fully evaporate off and leave a residue. What was left over no matter how much I heated the watchglass was stagnant droplets as if I was using dirty glass and I had poured a solution over it. (i.e. diry volumetric flask after pouring solution out, has stagnant droplets of water)
I'm not sure if the oily substance was another compound. Hopefully it is not. I ran a plate and it showed 1 strong spot and 1 weak weak spot and my prof. said that it looks like it is one compound. This is the reason I tried to evaporate off the solvent and see if I could just see one compound or 2 after using this to spot another plate, therefore elminating the chance that it is solvent interaction that is causing the second spot.
I will try to analyze the CH2Cl2 with the unknown in it and see what happens.
Thank you Dr.Bob
I'm not sure if the oily substance was another compound. Hopefully it is not. I ran a plate and it showed 1 strong spot and 1 weak weak spot and my prof. said that it looks like it is one compound. This is the reason I tried to evaporate off the solvent and see if I could just see one compound or 2 after using this to spot another plate, therefore elminating the chance that it is solvent interaction that is causing the second spot.
I will try to analyze the CH2Cl2 with the unknown in it and see what happens.
Thank you Dr.Bob
1 answer