[DoctorDomo]

I'm running a reaction which can product numerous possible isomers, all of which should be relatively non polar. I got a white precipitate in one of my flasks, I vacuum filtered it and washed it with the reaction solvent (which cleaned the yellow color out of it). Now I need to figure out what this material is. It'd be cool if its a new compound, and conversely it would be s#*$ if it was just unreacted potassium carbonate which was in the reaction mixture.

The compound is highly water soluble, sparingly soluble in methanol and insoluble in everything else I tested, including acetone. So I tested the pH of a solution, and it turned the strip green (pH . Then I did a melting point test and saw that even at 300C nothing melted. Bad sign. The worst sign was when I dropped a bit of the material in acid and observed effervescence. Theres definitely carbonate in there, but one clue that its not just carbonate is the bright blue fluorescent blotch it produces on silica TLC plates under UV light. I'm pretty sure K2CO3 isn't fluorescent, and this is a different colour to any of the fluorescent starting materials and products.

I ran an IR and observed what looks like a carbonyl peak, but its clearly impure and that peak might be from the carbonate or some residual DMF. I will have an HNMR soon enough, but in the meantime what can I do to narrow down what this substance is?

[Dan]

You're not providing enough information - you should at least tell us what the reagents/conditions were.

NMR and mass spec would also help enormously.

Your question as it stands is impossible to answer.

[ThePostDoc]

sounds like a salt.  Do a flame test with a tiny amount.  If the flame turns a deep orange-red color most likely you have a potassium salt.

http://en.wikipedia.org/wiki/Flame_test

[TheUnassuming]

Agreed, we need to know more in order to help in any meaningful way.

With any new product you need to get into the habit of immediately getting a proton/carbon NMR and mass (LCMS is even better) of your compound.  IR is great for some things, but most journals don't ask for it for compound characterization anymore for a reason. 

[Arkcon]

sounds like a salt.  Do a flame test with a tiny amount.  If the flame turns a deep orange-red color most likely you have a potassium salt.

http://en.wikipedia.org/wiki/Flame_test

The potassium flame test is very difficult for a novice to perform well, and orange-red isn't the color associated with potassium.