boiling point vs. pressure nomograph
The separation unit of a distillation (or countercurrent exchanges overall) is the theoretical plate (originally from petroleum distillation towers),
Each separation step must be at equilibrium. Your basic lab rig is might be three theoretical plates at best, vapor vs. liquid in a hollow vertical column. Efficient physical separation demands thin film countercurrent flow to maximize surface area/volume, hence packed columns then
spinning band distillation
wherein a tightly fitting teflon screw thread spinning like all get out jams fluid condensate downward against vapor flowing upward. Net output is a drop every now and again.
The natural evolution of phase exchange is gas chromatography then liquid chromatography (much denser medium - look up the exchange maths). HPLC using monodisperse spheres with surface exchange only can have theoretical plate heights of a few microns, giving tens of thousands of theoretical plates in a rather short column.