Synthesis of 3-Nitrobenzaldehyde
Abstract
This experiment is about the synthesis of 3-nitrobenzaldehyde through nitration. The nitration of benzaldehyde is an example of an electrophilic aromatic substitution reaction, in which a proton of an aromatic ring is replaced by a nitro group. Many aromatic substitution reactions are known to occur when an aromatic substrate is allowed to react with a suitable electrophilic reagent, and many other groups besides nitro may be introduced into the ring. Although the reaction produced a low yield at the end, the yield is calculated from the reaction and limiting reagent.
Keywords: electrophilic aromatic substitution, nitration, aldehyde, nitrating group
Introduction
Electrophilic substitution happens in many of the reactions of compounds containing benzene rings - the arenes. Electrophilic Aromatic Substitution is a reaction in which the hydrogen atom of an aromatic ring is replaced as a result of an electrophilic attack on the aromatic ring (Attkins & Carey, 1990). There are steps to an electrophilic substation. First, attack of the electrophile on the aromatic ring, creating a resonance-stabilized carbocation called an arenium ion, which is an ion that is the result of an electrophilic attack on a benzene ring. And deprotonation of the arenium ion by a weak base to regain aromaticity.
Nitration is defined as replacing a hydrogen with a nitro (NO2) group. Nitration requires the presence of sulfuric acid (H2SO4) as a catalyst.
Mechanism of Nitration.
A. Overall reaction:
B. Mechanism:
The nitronium ion is the electrophile generated by the nitric acid/sulfuric acid mixture. The reaction is "sluggish" with nitric acid-sulfuric acid. Note that the reactions are reversible, and shifted to the desired products by manipulating concentrations (i.e., adding more reactant, removing a product, etc.) The electrophile is the "nitronium ion" or the "nitryl cation", NO2+. This is formed by reaction between the nitric acid and the sulphuric
This experiment is about the synthesis of 3-nitrobenzaldehyde through nitration. The nitration of benzaldehyde is an example of an electrophilic aromatic substitution reaction, in which a proton of an aromatic ring is replaced by a nitro group. Many aromatic substitution reactions are known to occur when an aromatic substrate is allowed to react with a suitable electrophilic reagent, and many other groups besides nitro may be introduced into the ring. Although the reaction produced a low yield at the end, the yield is calculated from the reaction and limiting reagent.
Keywords: electrophilic aromatic substitution, nitration, aldehyde, nitrating group
Introduction
Electrophilic substitution happens in many of the reactions of compounds containing benzene rings - the arenes. Electrophilic Aromatic Substitution is a reaction in which the hydrogen atom of an aromatic ring is replaced as a result of an electrophilic attack on the aromatic ring (Attkins & Carey, 1990). There are steps to an electrophilic substation. First, attack of the electrophile on the aromatic ring, creating a resonance-stabilized carbocation called an arenium ion, which is an ion that is the result of an electrophilic attack on a benzene ring. And deprotonation of the arenium ion by a weak base to regain aromaticity.
Nitration is defined as replacing a hydrogen with a nitro (NO2) group. Nitration requires the presence of sulfuric acid (H2SO4) as a catalyst.
Mechanism of Nitration.
A. Overall reaction:
B. Mechanism:
The nitronium ion is the electrophile generated by the nitric acid/sulfuric acid mixture. The reaction is "sluggish" with nitric acid-sulfuric acid. Note that the reactions are reversible, and shifted to the desired products by manipulating concentrations (i.e., adding more reactant, removing a product, etc.) The electrophile is the "nitronium ion" or the "nitryl cation", NO2+. This is formed by reaction between the nitric acid and the sulphuric
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