basic rotory evaporator operation questions

[RoundBottom]

1. how does one determine the temperature of something in a rotory evaporator?  i cannot see any places for a thermometer in the basic buchi and yamato models.  does one extrapolate from the bath temperature? 

2. how does one make the distilling flask stay on the vapour tube when not using a vacuum?  i would assume a keck clamp or similar.

SWIM is about to buy a yamato RE-51.  niceley programmable... automated lift mechanism, automated bath temp control, timer control, etc.

[hest]

1 Why do you want to know the temeparture of the solvent you are stripping off ?? usual you don't care. But iff you vant to use the rotorvap as a destilation'mashine' fittings for mounting a thermometer, refluxing, ect. is out there.
2 yes, usual there is a clamp mounted on the pice of glass you stick the flask onto.

[RoundBottom]

mainly want to know so one can recycle the solvents.  thanks for the info.

[Rhodium]

If you want to recycle your solvent, simple recovery in a rotavap isn't enough to purify them (except in special cases, where there are no water or other solvents contaminating it), as the separation efficiency is almost nonexistant in such an apparatus.

Instead make a crude recovery of all your volatiles using the rotovap, then dry the mixture, filter off the drying agent and then carefully distill the solvent slowly, collecting only what comes over in about a ~5°C range, any pre- and post-run you may fractionally redistill to recover even more of your solvent.

[RoundBottom]

thanks for that, rhodium... that explains why there is no thermometer port.  rotavaps are for stripping solvents only... they're still nice machines.