[SHELabGuy]

What would be the ideal settings for distilling methylene chloride / dichloromethane in a rotory evaporator?  Since the stuff boils at only 106F or so, it seems you wouldnt want to pull much vacuum... or am I wrong?  What would be the most efficient  or recommended vacuum/temperature settings?  Assume coolant is -60c to -80c.

[fledarmus]

What do you mean by efficient distillation? Separation of the compound of interest from other materials with similar but not identical boiling points?

The boiling point of methylene chloride is so low that if you are actually trying to purify it, adding a vacuum is counterproductive. The difference in boiling point between the dichloromethane and the impurity you are trying to isolate it from gets less as the boiling points are reduced.

If, on the other hand, you are just trying to remove the dichloromethane as fast as possible from a non-volatile product and want to do it with the lowest possible heat, a good vacuum pump will drop the boiling point of dichloromethane very nearly to room temperature.

I have found this tool to be helpful for predicting boiling points at different temperatures...

http://www.sigmaaldrich.com/chemistry/solvents/learning-center/nomo-assets.html

[JaniceColins]

I am not from chemical field that's why this site and forum is so helpful for me. What is rotary evaporator?

[Borek]

http://en.wikipedia.org/wiki/Rotovap