Students can go through TS Inter 2nd Year Chemistry Notes 13th Lesson Organic Compounds Containing Nitrogen will help students in revising the entire concepts quickly.
TS Inter 2nd Year Chemistry Notes 13th Lesson Organic Compounds Containing Nitrogen
→ Amines can be considered as derivatives of ammonia obtained by replacement of one, two or all the three hydrogen atoms by alkyl and / or aryl groups.
→ The amines are classified as primary (1°), secondary (2°) or tertiary (3°) amines. They are represented by the general formulas RNH2 (Primary amines), R2NH or RNHR’ (Secondary amines) as R3N or R NR’ R” or R2 NR’ (Tertiary amines).
→ All the three types of amines behave as Lewis bases due to the presence of one unshared electron pair on nitrogen atom.
→ Amines are obtained from nitrocompounds, halides, amides, imides etc.
→ Primary and secondary amines are involved in intermolecular association due to inter- molecular hydrogen bonding. Tertiary amines have no intermolecular hydrogen bonding due to the absence of H-atom on nitrogen. Hence the boiling points of isomeric amines are in the order.
1° > 2° > 3°
→ The order of basicity of amines in the gaseous phase follows the order :
3° > 2° > 1° > NH3
→ In aqueous solution the order of basicity of substituted amines is
(CH3)2 NH > CH3 NH2 > (CH3)3 N > NH3
(C2H5)2 NH > (C2H5)3N > C2H5NH2 > NH3
→ Aliphatic and aromatic primary amines on heating with chloroform and ethanolic KOH form isocyanide or carbylamine which are foul smelling substances. Secondary and tertiary amines do not give this reaction.
→ Benzene sulphonyl chloride (C6H5.S02Cl) is known as Hinsberg’s reagent. It is used to distinguish between primary, secondary and tertiary amines and also to separate the amines from their mixture.
→ -NH2 group is ortho and para directing and a powerful activating group in electrophilic substitution reactions of aniline.
→ Diazonium salts have the general formula
R N2 X where R stands for an aryl group and X ion may be Cl, B̅r̅, HS̅O̅4 , BF̅4 etc.
→ Diazonium salts are very good intermediates for the introduction of – F, – Cl, – Br, – I, – CN, – OH, – NO2 groups into the aromatic ring.
→ Alkyl cyanides are alkyl derivatives of hydrogen cyanide and isocyanides are isomers of alkyl cyanides.
→ Alkyl cyanides are usually obtained from alkyl halides, aldoximes and amides. Alkyl isocyanides are formed from alkyl halides by reacting with silver cyanide. Alkyl cyanides are used as intermediates in the multistep organic synthesis.