CHAPTER

ORGANIC COMPOUNDS CONTAINING NITROGEN

Syllabus

Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, identification of primary, secondary and tertiary amines.

Cyanides and isocyanides - will be mentioned at relevant places in text.

Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry.

Chapter Analysis

2016 2017 2018

List of Topics D OD OD D/OD

IUPAC Name 1Q ĪO 1Q

(1 mark) (1 mark) (1 mark)

Name Reaction 1Q 1Q 1Q

(2 marks) (2 marks) (5 marks)*

Properties 1Q

(5 marks)*

reaction Writing the structure of 1Q<br>(3 marks)* (5 marks)* 1Q

compounds/products in a Give reason 1Q 1Q 1Q 1Q

(3 marks) (3 marks) (3 marks) (5 marks)*

Chemical test to 1Q

distinguish between (5 marks)

• * One question of 5 marks with two choices was asked. First choice has a question of 3 marks on Name Reactions and a question of 2 marks of give reason. Second choice has a question of 3 marks on writing the structure of main products in the reactions, a question of 1 mark on chemical test to distinguish between pair of compounds and a question of 1 mark on arranging given compounds in their increasing order of <math>{}_{p}K_{b}</math> values.

On the basis of above analysis, it can be said that from exam point of view, IUPAC name, Name reactions, writing the structure of products for the reactions and give reason are the most important types of questions from the chapter.

Revision Notes

➣ Amines: Amines are considered as amino derivatives of hydrocarbons or alkyl derivatives of ammonia. In these compounds, one, two or three hydrogen atoms are replaced by alkyl or aryl groups. Aliphatic amino compounds are called amino alkanes and aromatic amines are called amino arenes. e.g., CH₃NH₂, C₂H₅NH₂, C₆H₅NH₂ etc.

➣ Classification of amines:

<math>-NH_2</math> — N — -NH Primary Tertiary Secondary <math>(1^{\circ})</math> <math>(3^{\circ})</math> <math>(2^{\circ})</math>

287 ORGANIC COMPOUNDS CONTAINING NITROGEN

➣ Structure of amines:

Unshared electron pair

<math>-CH_3</math> CH₃—

<math>108^{\circ}</math>

<math>CH_3</math>

Pyramidal shape of trimethylamine

Nitrogen orbitals in amines are sp³ hybridised and the geometry is pyramidal. Due to the presence of unshared pair of electrons, the angle C—N—E is less than 109.5°.

• Nomenclature of some Alkylamines and Arylamines :

Amine Common name IUPAC name

<math>CH_3</math>—<math>CH_2</math>—<math>NH_2</math> Ethylamine Ethanamine

<math>CH_3</math>—<math>CH_2</math>—<math>CH_2</math>—<math>NH_2</math> n-Propylamine Propan-1-amine

<math>CH_3</math>—CH—<math>CH_3</math> Propan-2-amine

<math>NH_2</math> CH₃—N—CH₂—CH₃ N-Methylethanamine

Η <math>CH_3</math>—N—<math>CH_3</math> N, N-Dimethylmethanamine

<math>CH_3</math> <math>C_2H_5</math>—N—<math>CH_2</math>—<math>CH_2</math>—<math>CH_2</math> N, N-Diethylbutylamine N, N-Diethylbutan-1-amine

<math>C_2H_5</math> <math>NH_2 - CH_2 - CH = CH_2</math> Allylamine Prop-2-en-1-amine

<math>NH_2</math>—<math>(CH_2)_6</math>—<math>NH_2</math> Hexamethylenediamine Hexane-1, 6-diamine

<math>NH_2</math> Aniline or Benzenamine

<math>NH_2</math> <math>CH_3</math> o-Toluidine 2-Aminotoluene

<math>NH_2</math> 4-Bromobenzylamine or 4-Bromoaniline Br