[Super Newb]

When do we use air reflux and reflux with water passing through the condenser?

[discodermolide]

When do we use air reflux and reflux with water passing through the condenser?

I can't remember the exact temperatures, but with a solvent boiling around 160°C or above use an air condenser, anything below that use water. Look at Vogel's book on "practical Organic Chemistry". I' can't find my copy 
Remember water in at then bottom and out at the top otherwise it may crack the glass.

[Super Newb]

Wow! Thanks for your help I will go look up at the vogel's book.

[fledarmus]

There are also a few lower boiling solvents that are solids at room temperature or slightly below. tert-Butanol was the one that got me. Rather than condensing and dripping back into the pot, it solidified in the condenser.

So check both the freezing point and the boiling point of your solvent.