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प्रश्न
Explain the following reaction with a suitable example.
Hofmann elimination reaction
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उत्तर
- When tetraalkylammonium halide is heated with moist silver oxide, it gives quaternary ammonium hydroxide.
- Quaternary ammonium hydroxides on strong heating undergo β-elimination to give an alkene. This reaction is called Hofmann elimination.
- The least substituted alkene is obtained as a major product (in contrast to Saytzeff elimination).
e.g. Hofmann elimination reaction of N, N, N-Triethylpropylammonium iodide
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संबंधित प्रश्न
Write the chemical equation involved in the following reaction:
Hoffmann-bromamide degradation reaction
Give the structures of A, B and C in the following reactions :
Give the structure of A, B and C in the following reaction:
\[\ce{CH3CH2I ->[NaCN] A ->[OH-][Partial hydrolysis] B ->[NaOH + Br2] C}\]
Write the reaction of aromatic primary amine with nitrous acid.
Give a plausible explanation for the following:
Why are amines less acidic than alcohols of comparable molecular masses?
Explain the mechanism of action of hydroiodic acid on 3-methylbutan-2-ol.
Arrange the following in the increasing order of their pKb values:
C6H5NH2, C2H5NH2, C6H5NHCH3
Give the structures of A, B and C in the following reactions :
Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.
Answer in one sentence.
Which amide does produce ethanamine by Hofmann bromamide degradation reaction?
Answer the following
Identify A and B in the following reactions.
\[\ce{C6H5CH2Br->[alco.][KCN]A ->[Na/ethanol]B.}\]
Answer the following
Explain Gabriel phthalimide synthesis.
Answer the following
Explain the ammonolysis of alkyl halides.
Write reactions to prepare ethanamine from Acetonitrile.
Name the process of breaking C-X bond by ammonia in preparation of amines.
Write reactions to bring about the following conversions.
Acetamide to methylamine
Why cannot aniline be prepared by Gabriel phthalimide synthesis?
Acetamide on reduction using Na/C2H5OH gives ____________.
Which of the following amines exhibits maximum degree of intermolecular hydrogen bonding?
What is the molar mass of the amine formed when acetamide undergoes Hofmann bromamide degradation?
\[\ce{CH3-CN ->[Na/C2H5OH]}\]
The product formed is ____________.
Which nitrogen containing compound amongst the following would undergo Mendius reduction to furnish primary amine \[\ce{(R - NH2)}\]?
Which of the following reactions is appropriate for converting benzamide to aniline?
Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?
Identify 'A' and 'B' in the following conversions.
\[\ce{CH3 - I ->[Alc. KCN][\Delta] A ->[Na/C2H5OH] B}\]
Which of the following reagents is used in Mendius reduction reaction of alkyl cyanide?
Identify product B in the following reaction.
\[\ce{Aniline ->[NaNO2][HCl] A ->[KI] B}\]
Which of the following compounds is obtained when quaternary ammonium hydroxide is strongly heated?
Which of the following does NOT give carbylamine test?
Quaternary ammonium salt is formed:
Benzylamine may be alkylated as shown in the following equation:
\[\ce{C6H5CH2NH2 + R - X -> C6H5CH2NHR}\]
Which of the following alkylhalides is best suited for this reaction through SN1 mechanism?
In order to prepare a 1° amine from an alkyl halide with simultaneous addition of one \[\ce{CH2}\] group in the carbon chain, the reagent used as source of nitrogen is ______.
The source of nitrogen in Gabriel synthesis of amines is ______.
The best reagent for converting 2–phenylpropanamide into 2-phenylpropanamine is ______.
Hoffmann Bromamide Degradation reaction is shown by ______.
Reduction of aromatic nitro compounds using \[\ce{Fe}\] and \[\ce{HCl}\] gives ______.
Which of the following compounds is the weakest Brönsted base?
Which of the following methods of preparation of amines will give same number of carbon atoms in the chain of amines as in the reactant?
Under which of the following reaction conditions, aniline gives p-nitro derivative as the major product?
(i) Acetyl chloride/pyridine followed by reaction with conc.\[\ce{H2SO4 }\] + conc. \[\ce{HNO3}\].
(ii) Acetic anyhdride/pyridine followed by conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iii) Dil. HCl followed by reaction with conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iv) Reaction with conc.\[\ce{HNO3}\] + conc.\[\ce{H2 SO4}\].
Write following conversions:
acetanilide `->` p-nitroaniline
How will you carry out the following conversion?
How will you carry out the following conversion?
How will you carry out the following conversions?
Assertion: Only a small amount of \[\ce{HCl}\] is required in the reduction of nitro compounds with iron scrap and \[\ce{HCl}\] in the presence of steam.
Reason: \[\ce{FeCl2}\] formed gets hydrolysed to release \[\ce{HCl}\] during the reaction.
Assertion: Aromatic 1° amines can be prepared by Gabriel Phthalimide Synthesis.
Reason: Aryl halides undergo nucleophilic substitution with anion formed by phthalimide.
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Ethylamine can be prepared by the action of bromine and caustic potash on which compound?
Which of the following compound is expected to be most basic?
When primary amines are treated with HCl, the product obtained is which of the following?
Which of the following reaction DOES NOT involve Hoffmann bromamide degradation?
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Write a short note on the following:
Ammonolysis
Write short note on the following:
Ammonolysis
Write short note on the following.
Ammonolysis.
Write a short note on Ammonolysis.
