Drying Solution in Vacuum Oven: Difference in Speed?

[yaganon]

In a hypothetical situation. If I have a vacuum oven that has an internal volume of say 2 gallons. And I want to completely dry up a solution containing around 10 mL of water (~0.5 mol).

Would it make much difference if I bring the oven to a very low absolute pressure (say 5 in Hg or 17kPa) and disconnect the oven from the vacuum. as oppose to leaving the oven connected to the vacuum and constantly suck the water vapors out of the oven?

I do realize that the latter would be a faster way, but I'm wondering if the difference is really significant.

 

[Valerie Park]

The difference in using a vacuum oven to dry a solution with 10 mL of water (~0.5 mol) can be significant, depending on the temperature and pressure used. If the oven is left connected to the vacuum, it will continuously suck out the water vapors and therefore can dry the solution much faster than if the oven is brought to a low absolute pressure and disconnected from the vacuum. This is due to the fact that at lower pressures, the rate at which water evaporates from the solution is slower. However, the drying time will also depend on the temperature used in the oven, as higher temperatures can cause faster evaporation.