Nitration

Benzene is nitrated by refluxing with concentrated sulfuric acid and concentrated Nitric Acid at 50° C .

(1) 2H₂SO₄ + HNO₃ → 2HSO₄^1- + NO₂⁺ + H₃O⁺

(2) C₆H₆ + NO₂⁺ → C₆H₅NO₂ + H⁺

(3) H⁺ + H₃O⁺ + 2HSO₄^1- → H₂O + 2H₂SO₄

The Sulfuric Acid is regenerated and hence acts as a Catalyst .

The formation of a nitronium ion (the electrophile) from Nitric Acid and Sulfuric Acid is shown below:

Selectivity is always a challenge in nitrations, Fluorenone nitration is selective and yields a tri-nitro compound ^{or tetra-nitro compound ^[2} by tweaking reaction conditions just slightly. Another example of trinitration can be found in the synthesis of Phloroglucinol .

Other nitration reagents include Nitronium Tetrafluoroborate which is a true nitronium salt. This compound can be prepared from Hydrogen Fluoride , Nitric Acid and Boron Trifluoride ^{{Link without Title}}. Aromatic nitro compounds are important intermediates to Aniline s by action of a Reducing Agent .

REFERENCES

^{''2,4,7-Trinitrofluorenone'' E. O. Woolfolk and Milton Orchin Organic Syntheses , Coll. Vol. 3, p.837; Vol. 28, p.91 [http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0837 Article}

^{''2,4,5,7-tetranitrofluorenone '' Melvin S. Newman and H. Boden Organic Syntheses , Coll. Vol. 5, p.1029; Vol. 42, p.95 [http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p1029 Article}

^{''Benzonitrile, 2-methyl-3,5-dinitro-'' George A. Olah and Stephen J. Kuhn Organic Syntheses Annual Volume 47, page 56 , [http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0480 Article}

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Nitration