remove solvent under vacuum

[ruggerio]

Hello,

 

 

What does remove a solvent under high vacuum means?Does that means under reduce pressure?

 

Do i need a vacuum pump?

 

 

thanks

[Timmehhh]

Hello,

 

 

What does remove a solvent under high vacuum means?Does that means under reduce pressure?

 

Do i need a vacuum pump?

 

 

thanks

 

 

A rotary evaporator. And yes, under vacuum means reduce pressure (i.e. below atmospheric pressure: < 101 kPa)

 

You can attach a round bottom flask containing your solution. The device applies a vacuum and allows you to lower the rotating flask into a water bath which you can use to heat your solution and speed the process. You can also adjust the speed with which the flask is rotated. A condensor allows collection of solvent in another round bottom flask. This must be emptied appropriately after each use.

 

Note that different solvents require different pressures. For example water requires a much lower pressure than volatile organics. Some devices will have preset values for different solvents. If you are unsure you should start off with higher pressures before gradually reducing pressure to ensure you dont rapidly boil you solution. The process can take some time depending on the volume you need to evaporate.

Edited October 11, 2012 by Timmehhh

[hypervalent_iodine]

A rotary evaporator. And yes, under vacuum means reduce pressure (i.e. below atmospheric pressure: < 101 kPa)

 

You can attach a round bottom flask containing your solution. The device applies a vacuum and allows you to lower the rotating flask into a water bath which you can use to heat your solution and speed the process. You can also adjust the speed with which the flask is rotated. A condensor allows collection of solvent in another round bottom flask. This must be emptied appropriately after each use.

 

Note that different solvents require different pressures. For example water requires a much lower pressure than volatile organics. Some devices will have preset values for different solvents. If you are unsure you should start off with higher pressures before gradually reducing pressure to ensure you dont rapidly boil you solution. The process can take some time depending on the volume you need to evaporate.

 

Typically, rot evaps don't have the best pumps and all the joints means you tend to lose a bit of the vacuum. A rot evap will only take off so much solvent. When something specifies that it needs to be under high vacuum, it doesn't mean to use a rotary evaporator, it means you need a good, high vacuum pump and (probably) some sort of solvent trap. Something capable of going to 0.1 mm Hg.

 

 

ruggerio, it might help if we knew what specifically this was for?