Nitro compound
From Free net encyclopedia
Nitro compounds are organic compounds that contain one or more nitro functional groups (-N{{#if:{{{1|}}}|{{{1}}}|}}O{{#if:{{{1|}}}|{{{1}}}|}}2). They are often highly explosive; various impurities or improper handling can easily trigger a violent exothermic decomposition.
Aromatic nitro compounds are typically synthesized by the action of a mixture of nitric and sulfuric acids on a suitable organic molecule. Some examples of such compounds are trinitrophenol (picric acid), trinitrotoluene (TNT), and trinitroresorcinol (styphnic acid).
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Preparation
In organic synthesis various methods exists to prepare nitro compounds.
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Aliphatic nitro compounds
- Nitromethane adds to aldehydes in 1,2-addition in the nitroaldol reaction
- Nitromethane adds to alpha-Beta unsaturated carbonyl compounds as a 1,4-addition in the Michael reaction as a Michael donor
- Nitroethylene is a Michael acceptor in a Michael reaction with enolate compounds
- In nucleophilic aliphatic substitution sodium nitrite (NaNO2) replaces an alkyl halide
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Aromatic nitro compounds
- In electrophilic substitution nitric acid reacts with aromatic compounds in nitration
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Reactions
Nitro compounds participate in several organic reactions.
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Aliphatic nitro compounds
- Aliphatic nitro compounds are reduced to amines with hydrochloric acid and an iron catalyst
- Hydrolysis of nitro compounds yield aldehydes or ketones in the Nef reaction
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Aromatic nitro compounds
- Reduction of aromatic nitro compounds with hydrogen gas over a platinum catalyst gives anilines.
- The presence of nitro groups facilitates nucleophilic aromatic substitution.
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