TMH-JEE-Chemistry- book-chapters Ch.30 Amines Study Guide/Note

JEE syllabus:

JEE Syllabus

Amines:
Preparation, Properties, Reactions
Charcteristic reactions
Basicity of substituted anilines and aliphatic amines,
Preparation from nitro compounds,
Reaction with nitrous acid,
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
Carbylamine reaction;
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Main Topics Covered in the TMH Book

METHODS OF PREPARATION
PHYSICAL PROPERTIES
CHEMICAL REACTIONS
SYNTHETIC USE OF DIAZONIUM SALT
SEPARATION OF A MIXTURE OF AMINES

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Amines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.

NH3 - H = RNH2; (Primary amine) characteritic group NH2 amino
RNH2 - H = R2NH;(secondary amine) characteritic group NH imino
R2NH - H = R3N (tertiary amine) characteritic group N tert-nitrogen

The amines are classified as primary, secondary and tertiary according to one, two or three hydrogen atoms of ammonia are replaced by alkyl or aryl groups.

In addition, there is another class known as quaternary ammonium compounds. These compounds are regarded as derivatives of ammonium salts in which all the four hydrogen atoms are replaced by alkyl or aryl groups.

Nomenclature of amines

IUPAC NAMES

Aliphatic amines

Methanamine
Ethanamine
1-Propanamine
2-Propanamines
N-methylmethanamine
N-Methylethanamine
N,N-Dimethylmethanamine

Aromatic amines

Benzenamine - can also be written as amino benzene
2-Methylbenzenamine
3-Methylbenzenamine
4-Methylbenzenamine
N-Methylbenzenamine
N,N-Dieethylbenzenamine


Isomerism in amines

1. Chain isomerism
2. Metamerism
3. Position isomerism
4. functional isomerism

Preparation of amines

1. From alkyl halides
2. From Nitro compounds (specially mentioned in JEE syllabus)
3.From nitriles (cyanides) and isonitriles (isocyanides)
4. From amides
5. From oximes
6. from aldehydes and ketones

Industrial preparation
1. from alcohols
2.from aniline

Physical properties

1. State and smell
2. B.P.


Chemical Properties
1. Reaction with water (Basic character of amines) (specially mentioned in JEE syllabus)
2. Reaction with acids
3. Reaction with metal ions
4. Alkylation
5. Acylation (reaction with acid chlorides and acid anhydrides)
6. Benzoylation
7. schiff's base formation
8. Oxidation
9. Carbalamine reaction (specially mentioned in JEE syllabus)
10. Reaction with nitrous acid (specially mentioned in JEE syllabus)
11. Reaction with Grignard reagent
12. Carbon disulphide
13. Carbonyl chloride
14. Ring substitution in aromatic amines
15. coupling of diazonium salts (specially mentioned in JEE syllabus)
Sandmeyer and related reactions (specially mentioned in JEE syllabus)
The diazonium salts have the general formula ArN2+X-, where X- may be an anion like Cl-, Br- etc.

The group N2+ (-N≡N+) is called diazonium ion group.

Sandmeyer reaction is a substitution reaction.

In the substistution reactions, nitrogen of the salts is lost as N2 and different groups are introduced in its place.

Various substitution reactions of diazonium salts

1. Replacement by -OH group. By boiling or by steam boiling. Phenol is formed

2. Replacement by hydrogen. By treatment with hypophophorous acid. Benzene is obtained.

3. Replacement by Cl and Br group.When the salt is warmed with cuprous chloride or cuprous bromide the corresponding halide is formed. This reaction is called Sandmeyer reaction
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Past JEE Questions

How will you convert 4-nitroaniline to 1,2,3-tribromobenzene? 1990

1991
Identify A, B and c in the following reactions

C6H5COOH + PCl5--->A
A + NH3---> B
B+ P2O5---->C6H5CN
C6H5CN +(H2, Ni)--->C

Some of the reactants can be catalysts.

1994
How will you synthesize benzamide from nitrobenzene.

1997

How will you prepare m-bromoiodo benzene from benzene?

1998
Write the structures of two products of the reaction.

CH3CONHC6H5 (Br2,Fe) ---->

1998

Arrange the following in the decreasing order of basic character

Methylamine, dimethylamine, aniline, N-methylaniline


2000
How would you bring about conversion of Aniline to Benzylamine.

2001

Aspartame an artificial sweetener, is a peptide and has the following structure.
(Structure not given here by me)
i) Identify the four functional groups.
ii) Write the zwitter ionic structure
iii) Write the structures of the amino acids obtained from the hydrolysis of aspartame.
iv) Which of the two amino acids is more hydrophobic?


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web sites
Notes on the Classification, Structure and Nomenclature-naming of Organic compounds containing Nitrogen
http://www.docbrown.info/page07/orgNcmpds.htm