Friday, January 25, 2008

IIT JEE Revision Amines-Chemical Reactions

Amines Chapter

Characteristic Reactions or Chemical Properties

1. Reaction with water (Basic character of amines) (specially mentioned in JEE syllabus - Covered in more detail in a separate post)

2. Reaction with acids
Amines reacts with acids to form salts. The salts are ionic compounds and are soluble in water.

3. Reaction with metal ions
Amines combine with metal ions such as Ag+ and Cu2+ to form complex ions. The lone pair of electrons in -NH2 group is used to form a coordinate bond with metal ions.

For example, silver chloride dissolves in methylamine to form a soluble silver amine complex.

4. Alkylation
primary and secondary amines react with alkyl halides to form tertiary amines

5. Acylation (reaction with acid chlorides and acid anhydrides)
Primary and secondary amines react with acid chloride or acid anhydride to form substituted amides.

6. Benzoylation
Aliphatic and aromatic amines react with benzoyl chloride in the presence of a base such as pyridine or acqueous NaOH to form benzoyl derivatives in which C6H5CO- group is introduced.

7. schiff's base formation
Both aliphatic and aromatic primary amines react with aldehydes to form Schiff's bases or anils.

8. Oxidation
Primary aliphatic amines on oxidation with potassium permanganate followed by hydrolysis give aldehydes and ketones.

Secondry amines react with Caro's acid to give corresponding N-hydroxy amine.

Tertiary amines are oxidized by Caro's acid, ozone or H2O2 to corresponding N-oxides.

Aninline can be readily oxidized in the presence of K2Cr2O7 and H2SO4, and gives p-benzoquinone.

9. Carbalamine reaction (specially mentioned in JEE syllabus - covered separately)

10. Reaction with nitrous acid (specially mentioned in JEE syllabus - covered separately)

11. Reaction with Grignard reagent
Primary and secondary amines react with Grignard reagents to form alkanes.

Tertiary aliphatic amines do not react with Grignard reagent because they do not have hydrogen atom attached to the nitrogen atom.

12. Carbon disulphide
Primary amines react with carbon disulphide to form dithio-alkyl carbamic acids which decompose on heating with mercuric chloride (HgCl2) to give alkyl isothio cyanates. (Hoffman must oil reaction - a test for primary amines).

13. Carbonyl chloride
Primary and secondary aliphatic amines react with carbonyl chloride to form substituted ureas.

14. Ring substitution in aromatic amines
Aromatic amines give the aromatic substitution reactions as given by benzene.

15. coupling of diazonium salts (specially mentioned in JEE syllabus - covered separately)

16. Sandmeyer and related reactions (specially mentioned in JEE syllabus - covered separately)

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