Nice one, Sam.
The reaction proceeds more quickly when the sols. are boiled.My own experience of recrystallizing quinhydrone using hot water is that as the bp is approached it seems to decompose. Maybe due to a combination of excess temperature and some remaining oxidant in the solution. Or maybe I'm imagining things...dunno
[better to use ~ 50% aqueous MeOH for recrystallizing & not let it get too hot]
Therefore, I would only boil the reacting solution if it were Et
2O or maybe MeOH but not something with a higher bp.
Also quinhydrone seems to be considerably less soluble in water than hydroquinone, so I suspect the stuff would just precipitate out of solution. So chilling and filtration will recover most of the product (along with the charcoal but that can be dealt with).
This is based on my own experience of what happens when I prepare quinhydrone from hydroquinone using FeCl
3 or using I
2/H
2O
2, both of which are supposed to give benzoquinone, but for some reason don't
Fortunately, quinhydrone can definitely be substituted for benzoquinone in the synth of p-MeO phenol from hydroquinone.