Reply To: Why water evaporate on heating while oil doesn’t?

All liquids ultimately boil at some temperature. The vegetable oils are not easy to evaporate, because of high molecular weights and more than that the presence of the highly polar triester glyceride functional group. The glyceride ester function renders the oils vulnerable to decomposition at high temperatures, before the oil gets any chance to evaporate, under atmospheric pressure and open to the surroundings which would lead to oxidation and oxidative decomposition of the molecules. However, if you want you may distill oils under reduced pressure.