I am looking for a liquid which is not miscible (or very close) with water or vegetable oil. Ideally, I want to have a container which shows three layers (the three liquids) with clear boundary layers.
I was thinking that I should find a non-polar compound of very high molecular weight - such that difference in the density of that compound and oil is enough to draw it down out of the oil. However, I haven't found it yet.
I would prefer a compound which is non-toxic and non-flammable if possible.
It feels like such a simple question, I must be missing something.