Question

Doesn't suction pump blow out organic compound too, during the process of vacuum distillation?

Answer 1

Let us first define the `"normal boiling point....."`

Explanation:

The boiling point is strictly defined as the temperature at which the vapour pressure of the solution is EQUAL to the ambient pressure, and bubbles of vapour form directly in the liquid. The normal boiling point is defined when the ambient pressure is `"ONE ATMOSPHERE"`.

And so when we turn the kettle to make coffee, at the boiling point, when the water is `100` `""^@C`, we know that the vapour pressure of the boiling water is one atmosphere. Its vapour pressure pushes and displaces the atmosphere of air above it. Are you following me?

But if we reduce the pressure, i.e. by a means powerful vacuum pump, we directly reduce the ambient pressure, from `1*atm` to maybe less than `1xx10^-3*atm`. And thus we have to heat the material LESS to achieve a matching vapour pressure such that the solution boils.

And so when we distil an otherwise involatile organic liquid, vacuum distillation allows us to distill the liquid at a (reasonably) accessible temperature, i.e. `80-100` `""^@C` rather than `150-250` `""^@C`....

Are you with me?