[thedills]

How is it that sulfolane is selective to aromatics? Aromatics will dissolve into sulfolane and non aromatics repel similarly as to how oil seperates from water but will stick to other oils?

[pgk]

Sulfolane is a polar compound and therefore, it has solvation selectivity with respect of the solute's relative polarity.
On the other hand, aromatic hydrocarbons are electron rich and therefore, they are relatively more polar than aliphatic ones. Thus, a partial separation of aromatic hydrocarbons from aliphatic ones can be achieved by concentrated extraction with sulfolane. This method has no practical value in the lab but it is very convenient in the petrochemical industry because the partially separated hydrocarbons mixture is further fractionally distilled, which results significant energy savings compared to the fractional distillation of the initial hydrocarbons mixture.