[Grasshopper]

Hi.
I would like to use commercial anhydrous THF as a reaction solvent. Sigma supplies an inhibitor-free version with <20ppm peroxide as an impurity. Is it safe to heat this under reflux (under anaerobic conditions, of course), or should an inhibitor be added to prevent peroxide formation (too much inhibitor would adversely affect my reaction so I don't want to add it if I don't need it...)
Thanks very much.

[rolnor]

Its safe to reflux.

[Grasshopper]

Thanks 

[phth]

The common inhibitor is not volitile.  Just distill it from sodium metal or whatever.  There is no need to purchase things that will explode...

[BobfromNC]

The issue with inhibitor free solvents is that they can form peroxides on long storage, especially after opening to air.   They are fine to work with as long as you keep them sealed and don't keep them for more than a year after opening, in general.   It is only when concentrating them, you would even have a substantial risk, so you can just avoid concentrating your reaction to dryness before doing a water workup, which can be a good time to wash with thiosulfate if you are worried about peroxides.   Setting up a still is likely much more of a hazard than using peroxide free solvents, unless they are stored poorly and old.   

[kriggy]

Just make your own ? Mix with activated 3A sieves and keep for 72 hrs. See J. Org. Chem. 2010, 75, 8351–8354