The invention relates to a method for the liquid-liquid extraction of alcohols from aqueous solutions using at least one ionic liquid containing a tricyanomethide anion as solvent. 15 units of amyl groups per 1000 carbon atoms as determined by 13C Nuclear Magnetic Resonance. The main portion of the hitting face is a plate-like face made from a first material having a first density. The defects are placed in the three dimensional model of the system to generate a modified three dimensional model. A positioning structure is configured to releasably secure each printing unit at one position of a plurality of positions along the respective first and second arc configurations.