Amines| Class 12 Chemistry One Shot| NCERT Chapter 13 | CBSE NEET JEE

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The text discusses the various aspects of amines in chemistry, including their classification, naming conventions, preparation methods, properties, and reactions. It emphasizes the importance of understanding these concepts for accurately naming and synthesizing amines. The text covers the classification, naming, preparation, properties, and reactions of amines, underscoring the significance of these aspects in accurately handling and working with these chemical compounds.

Insights

  • Amines are classified based on the number of hydrogens replaced by alkyl groups, with primary, secondary, and tertiary amines having distinct structures.
  • Naming amines involves using specific prefixes for alkyl groups and following a systematic order, with IUPAC naming relying on the parent alkane structure.
  • Various methods, such as reduction of nitro compounds and ammonolysis of alkyl halides with ammonia, are utilized to prepare amines, impacting the type of amine produced.
  • Amines exhibit differing solubility properties based on their structure, with lower amines being gaseous and more soluble in water due to hydrogen bonding, while higher amines are not soluble and have higher boiling points.

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Recent questions

  • What are amines in chemistry?

    Amines are compounds with alkyl groups replacing hydrogen in ammonia.

  • How are amines prepared?

    Amines can be prepared through reduction of nitro compounds or ammonolysis of alkyl halides with ammonia.

  • What determines the solubility of amines?

    Solubility of amines is influenced by hydrogen bonding, with lower amines being more soluble than higher ones.

  • How is the basic nature of amines determined?

    The basic character of amines is determined by the number of alkyl groups attached, with tertiary amines being the most basic.

  • What are the reactions of amines with acids and bases?

    Amines react with acids to form salts and with strong bases to regenerate the amine.

Related videos

Summary

00:00

Amines: Chemistry of Alkyl Group Replacements

  • The video is about ammonia derivatives and amines in chemistry.
  • Amines are compounds where hydrogen in ammonia is replaced by alkyl groups.
  • Primary amines have one hydrogen replaced by an alkyl group.
  • Secondary amines have two hydrogens replaced by alkyl groups.
  • Tertiary amines have all three hydrogens replaced by alkyl groups.
  • Amines can also be classified as simple amines or mixed amines.
  • Simple amines have all alkyl groups the same, like trimethylamine.
  • Naming amines involves using prefixes for alkyl groups followed by "amine."
  • Common names for amines follow the order of alkyl groups alphabetically.
  • IUPAC naming for amines involves naming the parent alkane and adding "amine" at the end.

15:16

Naming and Synthesizing Amines: Essential Methods

  • Amines can be named based on the position of amino groups, with prefixes like Propane, Ethene, and Ethane used accordingly.
  • The longest carbon chain determines the naming of compounds, with prefixes like Ethan Amin and N-methyl ethanain used for specific structures.
  • Amines with alkyl groups attached to nitrogen are named by adding the alkyl group as a prefix, such as N-methyl benzene amine.
  • Various methods, including reduction of nitro compounds and ammonolysis of alkyl halides with ammonia, are used to prepare amines.
  • Reduction of nitro compounds involves passing hydrogen gas in the presence of catalysts like nickel or palladium to convert them into amines.
  • Another method of reducing nitro compounds involves reacting them with metals like iron in an acidic medium to obtain amines.
  • Ammonolysis is a crucial method where alkyl halides react with ammonia in ethanol solution to form amines through nucleophilic attacks.
  • The reaction results in the formation of ammonium salts, which can be further reacted with a strong base like NaOH to yield amines.
  • The type of amine formed depends on the degree of the amine and the alkyl halide used, with primary and secondary amines being produced accordingly.
  • Understanding these preparation methods is essential for naming and synthesizing amines accurately.

31:53

Amine Formation Methods and Reactivity Order

  • 3° amine results in a lighter halide, even quaternary ammonium salt can be converted to cotton ready
  • Aminolysis method explained, advantage of 3° amine in preventing primary amino product
  • Presence of excess alkyl halide leads to primary, secondary, tertiary, and quaternary ammonium salt formation
  • Alkyl halides in excess lead to various amine mixtures based on degree
  • Reaction mechanism between alkyl halide and ammonia determines primary amine formation
  • Reactivity order of halides: iodide, bromide, chloride due to increasing size and reactivity
  • Nitrile to amine conversion through catalytic hydrogenation or reduction with lithium aluminum hydride
  • Amines formed from nitriles maintain the same number of carbons, leading to amines with increasing carbon atoms
  • Gabriel thalimide synthesis method explained for primary amine formation, limitations in forming aromatic amines due to resonance in aryl halides
  • Hoffmann bromamide degradation method results in primary amines with one less carbon than the original amide, side products include Na2CO3 and NaBr

46:47

Formation and Properties of Amines

  • Amines are formed by the migration of the alkyl or aryl group from carbonate carbon to nitrogen.
  • Aromatic amines can be produced through this process.
  • The lower amines are gaseous, while those with more carbon atoms are liquid or solid.
  • Amines with aromatic amine rings are initially colorless but may develop color upon storage due to oxidation.
  • Lower amines are soluble in water due to hydrogen bonding, while higher amines are not soluble.
  • Primary amines are more soluble than secondary and tertiary amines.
  • Amines are soluble in organic solvents like ether and chloroform.
  • Amines with stronger intermolecular hydrogen bonding have higher boiling points.
  • Alcohol has a higher boiling point than amines due to stronger hydrogen bonding.
  • The basic nature of amines is determined by the number of alkyl groups attached, with tertiary amines having the highest basic nature.

01:02:26

Amine Basic Character and Reactions Explained

  • The basic character of amines is categorized into 1°, 2°, and 3°, with 2° amines being the most basic in ethyl-substituted cases.
  • In gaseous phase, the basic character order is 3° > 2° > 1°, while in aqueous phase, it is 2° > 3° > 1°.
  • Ethyl-substituted amines follow a basic character order of 2° > 3° > 1°, while methyl-substituted amines have a maximum basic character of 2°.
  • Aniline, an aryl amine, has more stable resonance structures compared to ammonia, resulting in a weaker basic character.
  • Electron-releasing groups in aniline increase its basic character, while electron-withdrawing groups decrease it.
  • Amines react with acids to form salts, and with strong bases to regenerate the amine.
  • Alkylation reactions involve the addition of alkyl groups to amines, progressing from 1° to 2° to 3° amines.
  • Acylation reactions involve the addition of acyl groups to amines using acid chlorides, acid anhydrides, or esters.
  • Aromatic and aliphatic primary and secondary amines show acylation reactions, while tertiary amines do not.
  • In acylation reactions, a hydrogen from the amine is replaced by an acyl group, forming a new compound.

01:17:15

Amine Reactions: Substitution and Acylation Reactions

  • The reaction involves the use of a strong base and basic nature bases.
  • A reaction is planned for the next day after removing the plus.
  • Nucleophilic substitution occurs, replacing hydrogen with a Sahil Group.
  • An example involves reacting ethenain with carbonic acid chloride.
  • The product of the reaction is ethanoine with a replaced hydrogen by a Rico Group.
  • The reaction is exemplified with a 2nd degree Amin, showing the replacement of hydrogen with a Ricoh Group.
  • Acylation is not possible with 3rd degree Amines due to the absence of hydrogen.
  • Aromatic Amines react with acid chloride to form benzene amide.
  • The benzoilation reaction involves replacing hydrogen with a benzoyl group.
  • The Karylamines reaction forms carbon from amine, creating isocyanide.

01:32:25

Aryl Compounds and Amine Reactions Explained

  • Aromatic compounds are referred to as Aryl.
  • Benzene sulfonile chloride is formed by adding SO2Cl to a benzene ring.
  • Primary amine reacts with benzene sulfonile chloride to form sulfonamide.
  • The sulfonamide compound is electron-withdrawing due to the cell phone group attached to nitrogen.
  • The compound is acidic in nature and soluble in alkali.
  • 1st-degree amine reacts with benzene sulfonile chloride to form alkali-soluble cell phones.
  • 2nd-degree amine reacts with benzene sulfonile chloride to form insoluble sulfonamides.
  • 3rd-degree amines do not react with benzene sulfonile chloride to form sulfonamides.
  • Primary, secondary, and tertiary amines have different reactions with benzene sulfonile chloride.
  • Aniline reacts with bromine water to form 2,4,6-tribromoaniline due to the high reactivity of the NH2 group.

01:46:41

Aniline Reactions and Diazonium Salts Formation

  • Aniline is treated with sulfuric acid (H2SO4) to form hydrogen sulfate.
  • The reaction results in para amino benzene, also known as sulfonic acid or cell finalic acid.
  • Nitration is carried out by reacting aniline with nitric acid in the presence of sulfuric acid.
  • The product of the reaction includes Nitro Aniline, meta Nitroaniline, and ortho Nitroaniline.
  • The reaction is influenced by the strong acidic medium and protonation of aniline.
  • The product distribution includes 51% Nitro Aniline, 47% meta Nitroaniline, and 2% ortho Nitroaniline.
  • The reaction is ortho-para directing when aniline reacts with nitric acid.
  • The control of the amino group is crucial to prevent the formation of meta products.
  • Diazonium salts are prepared by reacting aromatic amines like aniline with nitrous acid.
  • Diazonium salts exhibit physical properties like stability in water and solubility, decomposing easily in the dry state.

02:01:26

"Reactions with Azonium Salts in Chemistry"

  • Iodide group is difficult to introduce in brining due to its properties, requiring replacement at 2:30.
  • Potassium iodide reacts with azonium salt to release N2 gas, leading to product formation.
  • Halides like chloride, bromide, and iodide can be replaced in reactions using azonium salts.
  • Fluoroborate reacts with salt to produce fluoroborate precipitate and aryl chloride.
  • Introduction of fluoride to benzene ring involves reacting with fluoro boric acid to form aryl diazonium salt.
  • Reduction of azonium salts to form arene nitrogen involves using mild reducing agents like hypophosphorous acid.
  • Alcohol reacts with azonium salt to produce aldehyde upon oxidation.
  • Diazonium salt reacts with water at 83 Kelvin to form phenol through hydrolysis, releasing nitrogen gas as a byproduct.
  • Coupling reactions involving diazonium salts result in colored azo compounds with N double bond N connecting aromatic rings.
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