chemistry

Reduction of nitro compounds

Reduction of nitro compounds is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Reduction of nitro compounds rather than just read about it. In short: The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be affected by many reagents.

Key takeaways

Reduction of nitro compounds belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Reduction of nitro compounds to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Reduction of nitro compounds from memory before moving on to harder problems.

Reference excerpt

The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be affected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.

Aromatic nitro compounds

Reduction to anilines

The reduction of nitroaromatics is conducted on an industrial scale. Many methods exist, such as:

Catalytic hydrogenation using: Raney nickel or palladium-on-carbon, platinum(IV) oxide, or Urushibara nickel. Iron in acidic media. Sodium hydrosulfite Sodium sulfide (or hydrogen sulfide and base). Illustrated by the selective reduction of dinitrophenol to the nitroaminophenol. Tin(II) chloride Titanium(III) chloride Samarium Hydroiodic acid Metal hydrides are typically not used to reduce aryl nitro compounds to anilines because they tend to produce azo compounds. (See below)

Reduction to hydroxylamines Several methods have been described for the production of aryl hydroxylamines from aryl nitro compounds:

Raney nickel and hydrazine at 0-10 °C Electrolytic reduction Zinc metal in aqueous ammonium chloride Catalytic Rhodium on carbon with excess hydrazine monohydrate at room temperature

Reduction to hydrazine compounds

Treatment of nitroarenes with excess zinc metal results in the formation of N,N'-diarylhydrazine.

Reduction to azo compounds

Treatment of aromatic nitro compounds with metal hydrides gives good yields of azo compounds. For example, one could use:

Lithium aluminium hydride Zinc metal with sodium hydroxide. (Excess zinc will reduce the azo group to a hydrazino compound.)

Aliphatic nitro compounds

Reduction to hydrocarbons

Hydrodenitration (replacement of a nitro group with hydrogen) is difficult to achieve but can be affected by catalytic hydrogenation over platinum on silica gel at high temperatures. The reaction can also be effected through radical reaction with tributyltin hydride and a radical initiator, AIBN as an example.

Reduction to amines

Aliphatic nitro compounds can be reduced to aliphatic amines by several reagents:

Catalytic hydrogenation using platinum(IV) oxide (PtO2) or Raney nickel Iron metal in refluxing acetic acid Samarium diiodide Raney nickel, platinum on carbon, or zinc dust and formic acid or ammonium formate α,β-Unsaturated nitro compounds can be reduced to saturated amines by:

Catalytic hydrogenation over palladium-on-carbon Iron metal Lithium aluminium hydride (Note: Hydroxylamines and oximes are typical impurities.) Lithium borohydride or sodium borohydride and trimethylsilyl chloride Red-Al

Reduction to hydroxylamines Aliphatic nitro compounds can be reduced to aliphatic hydroxylamines using diborane.

The reaction can also be carried out with zinc dust and ammonium chloride:

R-NO2 + 4 NH4Cl + 2 Zn → R-NH-OH + 2 ZnCl2 + 4 NH3 + H2O

Reduction to oximes

Nitro compounds are typically reduced to oximes using metal salts, such as tin(II) chloride or chromium(II) chloride. Additionally, catalytic hydrogenation using a controlled amount of hydrogen can generate oximes.

References

Illustrations

Worked examples

Example 1 — a first encounter with Reduction of nitro compounds

Start with the simplest possible case. Write down what Reduction of nitro compounds claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Reduction of nitro compounds before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Reduction of nitro compounds ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Reduction of nitro compounds

In research: Reduction of nitro compounds appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Reduction of nitro compounds in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Reduction of nitro compounds is common in secondary-school and first-year university syllabi. It links to neighbouring topics Organic redox reactions, so understanding it makes those chapters shorter.
In everyday life: Look for Reduction of nitro compounds outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Reduction of nitro compounds in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Reduction of nitro compounds means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Reduction of nitro compounds out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Reduction of nitro compounds in simple terms?

The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be affected by many reagents.

Why does Reduction of nitro compounds matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Reduction of nitro compounds?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Reduction of nitro compounds.