http://www.sigmaaldrich.com/catalog/product/sigma/i0398?lang=en®ion=AU
According to that, the reagent grade stuff contains water, some carbonyls from oxidation and some non-descript acid or base.
And sorry, I neglected read the OP until just now. I was more talking about the stuff that you buy directly rather than the end product of your distillation. Not sure what it could be, though it doesn't sound like an additive to the isopropynol; especially if you've collected it in noticeable amounts. It's possibly a byproduct that's come about as a result of the distillation (depends on how you distilled it, however), though the green colour is odd. Otherwise, I guess it's some other impurity that's maybe reacted with the isopropanol. Is it water soluble at all?