John paul III - 20-6-2019 at 11:49
H2SO4 is used in comparatively huge quantities during nitration. That is of course because it serves to bind up water taking advantage of le chatelier
principle. I wondered why wouldn't it be replaced on industrial scale with bubbling of NO2 into the reaction mixture, since it would be twice as
effective at shifting the balance toward products while being cheaper. Is it's catalytic effect really important in nitration? I'd like to compare
reaction times for a typical nitration vs one where only a few drops of H2SO4 were added to serve only as catalyst. If you happen to know where to
find a write up of the latter kind of reaction or have personally experimented with it i'd be very interested to read that
caterpillar - 21-6-2019 at 10:47
H2SO4 in the mix with HNO3 creates a nitronuim ion (NO2+). This one is a more powerful nitrating agent than pure HNO3. And NO2 is not a good
replacement. You have to use N2O5 instead.