[pineapplegod]

Hi all,

I have synthesized a compound a few times this week, but my percent yield keeps being in the 150 to 170% range. Is there anyway to purify, or 'clean up' a compound without re-synthesizing it?

For context, my product is an organic solid.

I can't think of anything but vacuum filtration, which I performed in the experiment. It seems silly to run a simple distillation, as the product's melting point is unknown--I wouldn't know what temperature to distill at. I could try using a sep. funnel for liquid-liquid extraction, but that would require dissolving the product in acetone. Do people even run liquid-liquid extractions in acetone? I could recrystallize, but that would involve dissolving in acetone again . which doesn't seem like a good idea. I don't even know where to start with a flash column--the product doesn't even have a chemical name, so I don't know which solvent to dissolve the product in before loading it into the column. I guess I could run a TLC to find it's Rf and pick a solvent similar to that Rf. There's ought to be a better way.

Anyone have any thoughts on this?

[pineapplegod]

I should mention that after each synthesis I ran HNMR and kept finding starting material, hence why I repeated the experiment three times. The synthesis is only an hour, but it isn't solid science--perhaps more insanity--to keep doing the same thing but expecting different results. I think I will run TLC, find a proper solvent system, then run a flash column to purify the material.

[wildfyr]

This is impossible to diagnose without telling us at least somewhat what the compound is, and what the reaction conditions were. Just because it's never been made before (frankly, are you sure about that?) doesn't mean many critical properties can't be guessed by an experienced chemist.

You can't do liquid-liquid separation in acetone, its highly soluble in water. Ethyl acetate/water is typical. A LL separation is literally the least amount of work you could do to clean up a product.

Also, are you sure you completely removed all the solvent? Smell is a good way to check this if you don't take NMR.