3
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Can we add concentrated $\ce{H2SO4}$ and concentrated $\ce{HNO3}$ to anisole?

I heard that we can't add acids into phenol and aniline which make them blast.

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4
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Anisole (methoxybenzene) is an electron-rich arene that will react with sulfuric acid or nitric acid in an electrophilic aromatic substitution.

I suggest that you look the reaction up. Then grab a pencil, some sheets of paper and start to draw. Draw the arenium ions (Wheland intermediates) for the addition of the electrophiles at the different positions of anisole, have a look at the possible resonance structures and enjoy chemistry.


UPDATE

Btw, you can do the same reaction with aniline or phenol without causing an explosion.

My comment on aniline and phenol only works on paper but not in real life and Mithoron's comment on aniline and phenol is correct!

Nitroanilines and nitrophenols are synthesized in a different way. In principle, nitration of aniline is possible with a mixture of nitric and nitrous acid, or after protecting the aniline as its formanilide.

Technically, 4-nitroaniline is produced by reacting 4-chloronitrobenzene with aqueous ammonia at elevated temperatures in an autoclave.

Details can be found in Ullmann's Encyclopedia of Industrial Chemistry:

In the alternative continuous process, molten 4-chloronitrobenzene and 40 % ammonia liquor in a molar ratio of 1 : 17 are pumped at 20 MPa through a steel reaction coil held at 237-240 °C by oil bath heating. Inflow is controlled to give a contact time of ca. 10 min, and outflow is directed into an expansion chamber with a tangential flow of hot water to give, in quantitative yield, a suspension of product that is readily isolated and washed.

The same is true for the formation of 4-nitrophenol. Again, the starting material is 4-chloronitrobenzene, which is reacted with strong aqueous $\ce{NaOH}$ to yield the phenol.

These two reactions are examples for nucleophilic aromatic substitutions!

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  • 1
    $\begingroup$ aniline or phenol won't explode with conc. H2SO4 and conc. HNO3 but nitration won't occure but oxidation $\endgroup$ – Mithoron May 8 '15 at 16:42
  • $\begingroup$ Aniline can definitely be nitrated under these sorts of conditions. With phenol you might be better off using milder conditions e.g. just dilute nitric acid. $\endgroup$ – J. LS May 8 '15 at 17:18
  • $\begingroup$ @J.LS I thought so too, but according to the Ullmann, the direct nitrations don't seem to play a role nowadays. That is, at least on a technical scale. $\endgroup$ – Klaus-Dieter Warzecha May 8 '15 at 17:24
  • $\begingroup$ I'd be interested to know what reactions/synthetic approaches have replaced them in industry ! $\endgroup$ – J. LS May 8 '15 at 17:30
  • $\begingroup$ @J.LS I've added a procedure from Ullmann's Encyclopedia of Industrial Chemistry to my answer. $\endgroup$ – Klaus-Dieter Warzecha May 8 '15 at 17:43

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