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प्रश्न
Explain the following reaction with a suitable example.
Hofmann elimination reaction
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
An aromatic compound 'A' of molecular formula C7H7ON undergoes a series of reactions as shown below. Write the structures of A, B, C, D and E in the following reactions :
How do you convert the following: C6H5CONH2 to C6H5NH2
How do you convert the following: Ethanenitrile to ethanamine
Write a short note on the following:
Hoffmann’s bromamide reaction
Accomplish the following conversion:
Nitrobenzene to benzoic acid
Accomplish the following conversions: Benzyl chloride to 2-phenylethanamine
Accomplish the following conversions: Benzamide to toluene
Give the structures of A, B and C in the following reaction.
Write the reactions of aromatic with nitrous acid.
Explain the mechanism of action of hydroiodic acid on 3-methylbutan-2-ol.
Mention 'two' uses of propan-2-one.
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 :
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
Write a reaction to convert acetic acid into methylamine.
The following amines is the product of Gabriel phthalimide synthesis.
Name the process of breaking C-X bond by ammonia in preparation of amines.
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Write reactions for the preparation of ethanamine using Gabriel phthalimide synthesis.
Identify compound 'B' in following series of reactions?
\[\ce{Acetonitrile ->[Na/alcohol] A ->[NaNO2/dil.HCI] B}\]
Acetamide on reduction using Na/C2H5OH gives ____________.
Identify the major product (B).
What product is formed when \[\ce{R - C ≡ N}\] is hydrolysed?
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 of the following reactions is appropriate for converting benzamide to aniline?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
Identify the INCORRECT statement regarding Hofmann bromamide reaction.
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Alkyl halides are insoluble in water.
Reason (R): Alkyl halides have halogen attached to sp3 hybrid carbon.
Select the most appropriate answer from the options given below:
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?
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Reduction of aromatic nitro compounds using \[\ce{Fe}\] and \[\ce{HCl}\] gives ______.
Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain is ______.
Reduction of nitrobenzene by which of the following reagent gives aniline?
(i) \[\ce{Sn/HCl}\]
(ii) \[\ce{Fe/HCl}\]
(iii) \[\ce{H2 - Pd}\]
(iv) \[\ce{Sn/NH4OH}\]
The reagents that can be used to convert benzenediazonium chloride to benzene are:
(i) \[\ce{SnCl2/HCl}\]
(ii) \[\ce{CH3CH2OH}\]
(iii) \[\ce{H3PO2}\]
(iv) \[\ce{LiAlH4}\]
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.\[\ce{H2 SO4}\].
Suggest a route by which the following conversion can be accomplished.
How will you bring out the following conversion?
How will you carry out the following conversions?
Assertion: Hoffmann’s bromamide reaction is given by primary amines.
Reason: Primary amines are more basic than secondary amines.
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.
The Gabriels' phthalimide synthesis is used in the synthesis of
Ethylamine can be prepared by the action of bromine and caustic potash on which compound?
A compound 'A' on reduction with iron scrap and hydrochloric acid gives compound 'B' with molecular formula C6H7N. Compound 'B' on reaction with CHCl3 and alcoholic KOH produces an obnoxious smell of carbylamine due to the formation of 'C'. Identify 'A', 'B' and 'C' and write the chemical reactions involved.
Give reasons for the following:
Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.
Which of the following statement(s) is/are incorrect in case of Hofmann bromamide degradation?
Identify the compo ds A and B in the following reactions:
\[\ce{A ->[Nitrating mixture] B ->[(i) Sn/cone. HCI][(ii) NaOH] Aniline}\]
Write a short note on the following:
Ammonolysis
Write a short note on Ammonolysis.
Write a short note on the following:
Ammonolysis.
