Amines
Physical Properties
- The lower aliphatic amines are gases with fishy odour.
- Primary amines with three or more carbon atoms are liquid and still higher ones are solid.
- Aniline and other arylamines are usually colourless but get coloured on storage due to atmospheric oxidation.
- Solubility decreases with increase in molar mass of amines due to increase in size of the hydrophobic alkyl part
- The order of boiling points of isomeric amines is Primary > Secondary > Tertiary
Order of basicity
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The order of basicity of amines in the gaseous phase: tertiary amine > secondary amine > primary amine > $NH_3$
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The greater the size of the ion, lesser will be the solvation and the less stabilized is the ion
Reaction with arylsulphonyl chloride or Hinsberg’s reagent
PYQ-2024-Amines-Q1, PYQ-2023 General Organic Chemistry Q14
Benzenesulphonyl chloride $(C_6H_5SO_2Cl)$, which is also known as Hinsberg’s reagent, reacts with primary and secondary amines to form sulphonamides.
(i) The reaction of benzenesulphonyl chloride with primary amine yields N-ethyl benzenesulphonyl amide.The hydrogen attached to nitrogen in sulphonamide is strongly acidic due to the presence of strong electron withdrawing sulphonyl group. Hence, it is soluble in alkali
(ii) In the reaction with secondary amine, N,N-diethyl benzenesulphonamide is formed
Since N, N-diethyl benzenesulphonamide does not contain any hydrogen atom attached to nitrogen atom, it is not acidic and hence insoluble in alkali.
(iii) Tertiary amines do not react with benzenesulphonyl chloride. This property of amines reacting with benzenesulphonyl chloride in a different manner is used for the distinction of primary, secondary and tertiary amines and also for the separation of a mixture of amines
Preparation of Diazonium Salts
PYQ-2024-Amines-Q3, PYQ-2024-Amines-Q4, PYQ-2024-Amines-Q5, PYQ-2023 Amines Q3
Chemical Reactions
PYQ-2023 Amines Q6, PYQ-2023 Amines Q7, PYQ-2023 Amines Q8
Sandmeyer reaction
Gattermann reaction
PYQ-2024-Aldehydes_and_Ketones-Q8
Coupling reactions
PYQ-2024-Amines-Q4, PYQ-2024-Amines-Q5, PYQ-2024-Carboxylic_Acid_and_Derivatives-Q2,
Carbylamine or isocyanide test
PYQ-2024-Alcohols-Q7 PYQ-2024-Alcohols-Q3
Gabriel phthalimide synthesis
Hoffmann bromamide degradation reaction
