When use a reduced pressure distillation?
If heated when the product produce its decomposition it must be distilled under reduced pressure. The decomposition may occur with explosive violence and this can occur even at room temperature if impurities are present.
To overcome this difficulty, the liquid is distilled under reduced pressure, so that its boiling-point shall be definitely below its thermal decomposition point.
The video explains when it is useful to use a reduced pressure for make the distillation, the procedure but also all the pieces of a vacuum distillation