I was wondering if vacuum distillation can seperate azeotropic mixtures.
Consider the ethanol/water system. At 95.6% ethanol content, the system forms an azeotrope because the vapor composition matches the liquid composition:
As one can see, no further seperation occurs in the condensed ethanol phase (going to the right of the diagram).
One of my questions is: If we start with an 50/50 (v/v) ethanol/water mixture, will eventually all the ethanol boil off, i.e will the starting flask consist completely of water after distillation finished? I get that the received ethanol will only contain 95.6% ethanol, but will the starting mixture contain 100% water after ethanol is boiled off (going to the left of the diagram).
And another question is: At lower pressures, do the vapor composition curve and liquid composition curve intersect or is fractional distillation of ethanol/water possible? At pressures of down to 10 mbar?