This is essentially a compact batch-type fractional distillation unit in which the reboiler consists of a vessel mounted in a heating bath and with a packed column above. The vapors from top is condensed and can be refluxed as per requirement. The top product is sub-cooled and collected in receivers. The bottom product is finally drained from the reboiler through a drain valve. The units are available in vessel sizes of 20, 50, 100, 200, 300 & 500 L and is suitable for operation under atmospheric pressure and full vacuum