If you boil it off like that, you may well lose a significant portion of the flavourings too, since many of these will likely boil off at or below 78.1'C too. To prevent the loss of these compounds, you would need to distil the liquid, and recover the fractions containing them, while excluding only the ethanol fraction.
Even with fractional distillation though, I'm afraid you'll never be able to get rid of all the alcohol - it forms an azeotrope with most common diluents (water is best documented, but I believe it is at least as applicable to VG and other glycols, though the exact %ages may vary somewhat,) so although most of it can be extracted, once the proportion of alcohol is low enough in relation to the diluents, the vapour retains exactly the same composition as the liquid, and no amount of further distillation will reduce the %age ethanol.
This is sort of backwards from the way I usually approach azeotropes (I'm usually trying to concentrate an ingredient and exclude a diluent, not the other way round,) but I would guess that the minimum ethanol concentration that can be achieved by such distillation would be somewhere between 2-10% of the total volume. A lot of oxidation of the nicotine and flavouring compounds is also likely to occur, probably spoiling the taste (and possibly reducing the hit) somewhat - if I had to do it, I'd probably distil it under argon to reduce these potential reactions (though it might not reduce them much - the heat is likely to promote all sorts of unpredictable reactions between the various constituents, even in the absence of free oxygen.)
I'm afraid I can't think of a good way to entirely separate the constituents in this case -
salt-effect distillation with sodium acetate would probably do it, but it's going to leave a lot of undesirable sodium acetate in the
juice, which just replaces one problem with another (and would probably make your
juice taste strongly of salt and vinegar

)
All I can suggest really is to mix your own juice - then you can choose not to add any alcohol. It's a lot easier to not put it in in the first place than to try to take it out after it's been added.
More about azeotropes
here.
More about fractional distillation
here.