How do you prepare aniline with mechanism?
Aniline is prepared commercially by the catalytic hydrogenation of nitrobenzene or by the action of ammonia on chlorobenzene. The reduction of nitrobenzene can also be carried out with iron borings in aqueous acid. A primary aromatic amine, aniline is a weak base and forms salts with mineral acids.
How is nitration done in aniline?
A : Nitration of aniline can only be done by protecting −NH2 group through acetylation. R : Acetylation of aniline results in the increase of electron density at the benzene ring. If both Assertion and the Reason are true and the Reason is a correct explanation of the Assertion.
What is the mechanism of nitration reaction?
The mechanism for nitration of benzene: Step 1: Nitric acid accepts a proton from sulphuric acid and then dissociates to form nitronium ion. Step 2: The nitronium ion acts as an electrophile in the process which further reacts with benzene to form an arenium ion.
What is the nitration of aniline?
In nitration of aniline in strong acid (HNO3, H2SO4) aniline changes to anillium ion . Anillium withdraws electron density. Its effect is felt maximum at ortho followed by meta and then para position. Consequently very little of ortho nitrated product is formed.
What is the mechanism of toxicity of aniline?
Many of the adverse health effects of aniline are due in part to the formation of methemoglobinemia. Aniline converts the Fe+2 in hemoglobin to Fe+3 which impairs its oxygen transport capacity. The mechanism by which aniline produces methemoglobin in the blood appears to be related to an active metabolite.
Why aniline is ortho and para directing?
NH2 group in aniline is ortho and para directing group because they can realese electrons towards ring due to resonance and at the same time they withdraw the electrons towads themselves from aromatic ring due to +1 effect.
Why nitration of aniline is difficult?
The nitration of aniline is difficult because aniline gets oxidised into protonated aniline. This aniline type gives 47% of m-nitroaniline.
Why nitration of aniline is very slow?
The nitration of aniline is difficult because aniline gets oxidized into protonated aniline. Direct nitration of aniline is not a feasible process because nitric acid oxidizes most of aniline to give tarry oxidation products along with only a small amount of nitrated products.
What do you understand by nitration explain the mechanism of nitration of benzene?
The nitration of benzene Nitration happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO2. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid at a temperature not exceeding 50°C.
What do you understand by nitration describe the mechanism of nitration of benzene?
1 Answer. Nitration benzene reacts with a mixture of concentrated nitric acid and concentrated sulphuric acid at 50°C to form nitrobenzene. Mechanism: This involves the following steps. Step 2: The electrophile NO2+ attacks the benzene ring to form a carbocation which is resonance stabilized.
Which product is obtained by the nitration of aniline?
Direct nitration of aniline with nitric acid gives a complex mixture of mono, di- and tri- nitro compounds and oxidation products. If −NH2 group is protected by acetylation and then nitrating mixture, p-isomer is the main product.
Is aniline an ortho para director?
The aniline amino group is ortho and para-directing, while meta-directing is aniline hydrogen chloride.
What is the resonating structure of aniline?
Resonance structure of aniline: In aniline and other arylamines, the amino group is directly attached to benzene ring. Conjugation of lone pair of electrons stabilizes aniline. The lone pair is not easily available for protonation.
Why nitration of aniline is meta-directing?
Nitration is carried out in an acidic medium. In a strongly acidic medium, aniline is protonated to give anilinium ion (which is meta-directing). For this reason, aniline on nitration gives a substantial amount of m-nitroaniline.
Is aniline op directing?
Why does nitration of aniline produce meta product?
The m-Nitroaniline is also formed in a significant quantity because here very strong acidic conditions are being used due to which some of the aniline molecules get protonated to anilinium ion. The −NH+3 group is electron withdrawing and m-directing due to which we get a significant amount of the meta product.
Why aniline is protected before nitration?
The hurdles for the nitration of aniline are overcome by the protection of amino group by acetylation. The acetyl group reduces the reactivity of the ring and thus its oxidation does not occur easily with nitric acid HNO3.
Why is group of aniline protected before nitration?
Why is nitration difficult?
Nitrogen of nitro benzene is difficult as it contain electron with drawing group,making compound electron elements.
How is nitrobenzene reduced to aniline?
Nitrobenzene is reduced to aniline by Sn and concentrated HCl. Instead of Sn, Zn or Fe also can be used. Aniline salt is given from this reaction. Then aqueous NaOH is added to the aniline salt to get released aniline.
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