I have had a quick search but could find no direct reference to anyone gassing with xylene. I am assuming that it would be as equally effective as toluene. Is this correct?

Gassing in xylene works well. It can hold a little bit more more water per liter than toluene, but has about the same properties of toluene like density, except xylene's BP is slightly higher than toluene.

yeah... mabey dry it first

Are u sure xylene hold more water then toluene?
I think its the opposite

From msds sheets:

For Xylenes

H2O/oil = 0.00075

and for Toluene

H2O/oil  = 0.0026

So toluene can hold 2.6 part water per thousand part toluene
and xylene 0.75 parts per thousand


As for gassing, xylene works great. I never used anything else and never had any problems. Of course always dry your xylene with epsom salts before gassing.

I have gassed in both xylene and toluene, there were no strikingly noticeable yield differences as both were done on the same scale. If you are gassing, I can't stress how important dryness is. When there is water contamination, there is a mess.

When solvents are frac-distilled, is it necessary to use drying agents as well..?
Thanks
or UTFSE?

UTFSE. It depends on if the solvents form azeotropes with water. Ethanol for example cannot be fractionately distilled to more than ~95%, to get 99%+ ethanol you need to use drying agents like Mg/I₂ or CaO (see TFSE).

Why do you not evapourate/softly boil out the water for your  dryness? Adding an alcohol (IPA, EtOH, MeOH..) should form an even easier to distill tertiary azeotrope by which the remaining nonpolar will get as nonaquaeous as can be made by means of distillation.  Boiling points differ more than 20°C for water/xylene and even more for the tertiary azeaotrope as far as I remember - no problem.

Can dry ice be dropped into a solvent to scavenge/freeze out the H2O?

Just a guess, but I would've thought that the more the dry ice cools the solvent to freeze out any water, the more prone the solvent will be to further moisture condensing into it from the atmosphere due to it being chilled...

Correct me if I'm wrong, but intuitively I'd say this won't work well to try the solvent.

...Anansi

CO2 will cause formation of carbonate from the freebase, which may precipitate depending on its solubility in the hydrocarbon you choose (toluene or xylene). When you gas, you'll neutralize the carbonate and form more water. Just follow the standard procedure.