Compound containing nitrogen

based on maharashtra board 2015 syllabus.

1. Compound containing Nitrogen By Azeem

2. Nitro Compound General method of preparation- Nitration of alkanes From alkyl halides From salts of α - halogeno carboxylic acid From primary amines From a- nitroalkenes (2methyl nitropropene ) From oximes ( aldoxime +O in trifluoroperoxy acetic acid)

3. Reaction of nitroalkane Reduction Hydrolysis Halogenation Reaction with nitrous acid Condensation with aldehydes and ketones Nitro Compound

4. Classification of amines

5. Physical Properties of Amines The methylamines (mono-, di-, tri-) and ethylamine are gases at room temperature , other amines are liquid at room temperature. Amines are irritating to the skin, eyes, and mucous membranes and are toxic by ingestion. Aromatic amines are generally toxic. Amines are readily absorbed through the skin and affect both the blood and the nervous system. Amines B.P are higher than alkane but not in alcohol.

6. Both amine and ammonia are produce basic aqueous solution. Amine and ammonia are weak base due to accepter of proton. NH 3 + H 2 O → NH 4 + OH Increase mass decrease solubility. Colourless . Physical Properties of Amines

7. Nomenclature of amines

8. Method of preparation of amines From alkyl halide: by ammonolysis From alkyl halide: Gabriel phthalimide synthesis(alkylation of phthalimide ) From oximes , alkyl cyanides, amides and nitro compounds: by reduction From oximes From alkyl cyanide(alkyl nitriles) From amides From nitro compounds From amides: by hoffman bromamide degradation

9. 1. From alkyl halide: by ammonolysis H-NH 2 100˚C under pressure

10. 2. From alkyl halide: Gabriel phthalimide synthesis

11. 3. From oximes , alkyl cyanides, amides and nitro compounds: by reduction

12. a. From oximes Aldoxime or ketoximes are reduce by sodium and ethanol to primary amine. R- CH= N-OH + 4[H] → R-CH 2 -NH 2 + H 2 O Ketoxime . Acetaloxime .

13. b. From alkyl cyanide(alkyl nitriles ) Alkyl cyanide on reduction by Na and ethanol give primary amine. R-C ≡ N + 4[H] → R-CH 2 -NH 2 Eg . Acetonitrile and Propanenitrile .

14. c. From amides 4[H]

15. d. From nitro compound Nitro compounds are reduced by tin( Sn ) or iron and con HCl to corresponding primary amines. R- NO 2 + 6[H] → R- NH 2 + 2H 2 O Eg . Nitrobenzene. Nitropropane .

16. e. Hoffman bromamide degradation

17. Reaction of Amines Basic nature of amines Action of nitrous acid (1⁰ amine , 2⁰ amine, 3⁰ amine) 3. Acylation of amines Alkylation of amines: Hoffmann's exhaustive alkylation Hoffmann elimination Hoffmann’s carbylamines test/ isocyanides test Reaction with arylsulphonyl chloride: Hinsberg’s test Electrophilic aromatic substitution a) Bromination b) Nitration c) sulphonation

18. 1. Basic nature of amines R- NH 2 + H + X → R-NH 3 + X - ammonium salts R-NH 3 + X - + NaOH → R-NH2 + NaX + H 2 O This shows that the reaction is reversible. C 2 H 5 -NH 2 + HCl < ==> C 2 H 5 -NH 3 + Cl - Ethylamine ethyl ammonium chloride Aqueous solutions amines are basic, and they turn red litmus paper blue. R-NH 2 + H-O-H  R- NH 3 + + OH - Weak base strongerbase

19. 2. Action of nitrous acid Primary, secondary & tertiary amines react differently with nitrous acid. Since nitrous acid is unstable, it is prepared in situ(Latin- reaction mixture) at 273K- 278K. NaNO 2 + HCl → NaCl + HNO 2 Except methyl and ethylamine, all primary amine give aliphatic diazonium salt.

20. Primary amine: (HNO 2 ) eg . Aniline R – NH 2 + NaNO 2 + 2HCl → [ R- N 2 + Cl - ] + NaCl + 2H 2 O Alkyl diazonium chloride Secondary amine : (HNO 2 ) eg . diethylamine R 2 – NH + NaNO 2 + HCl → R 2 N-N=O + NaCl + 2H 2 O N- nitroso dialkylamine Tertiary amine: (HNO 2 ) eg . triethylamine R3 – N + NaNO 2 + HCl → [ R3- NH] + NO 2 - + NaCl trialkyl ammonium nitrate 2. Action of nitrous acid

21. 3. Acylation of amines Amine react with acyl chloride in presence of pyridine. R- NH 2 + X-CO-R  R- NH – CO –R + HX Eg . Ethylamine Silimalary reaction in acetic anhydride, R- NH 2 + (CH 3 - CO-) 2 OR-NH-CO-CH 3 + CH 3 - COOH Amines ethanoic anhydride alkyl acetamide Eg . Aniline

22. 4. Alkylation of amines: Hoffmann's exhaustive alkylation R- NH 2  R 2 NH  R 3 N  R 4 N + X - 2⁰ amine 3⁰ tetraalkyl ammonium halide Eg . Methylamine Eg . Dimethanamine Eg . N,N- dimethyl aniline RX RX RX

23. 5. Hoffmann elimination Tetra alkyl ammonium halide on heating with moist Ag 2 O form tetra-alkyl ammonium hydroxides. This is deliquescent crystalline solid and basic in nature. ( of a solid) tending to absorb moisture from the air and dissolve in it. On heating undergo β -elimination to form alkene, tertiary amine and water. C 2 H 5 N - (CH 3 ) 3 + I - + AgOH  C 2 H 5 -N + (CH 3 ) 3 OH - + AgI Ethyltrimethyl ammonium iodide C 2 H 5 -N + (CH 3 ) 3 OH -  CH 2 =CH 2 + (CH 3 ) 3 N + H 2 O Ethyltrimethyl ammonium hydroxide

24. 6. Hoffmann’s carbylamines test/ isocyanides test R-NH 2 + CHCl 3 + 3KOH → R- NC + 3KCl + 3H 2 O Eg . Ethylamine and aniline.

25. 7. Reaction with arylsulphonyl chloride: Hinsberg’s test

26. 8. Electrophilic aromatic substitution Bromination

27. Bromination

28. Nitration

29. Nitration Aniline on acetylation on heating 298K.

30. Sulphonation

31. Preparation of Diazonium Salt’s

32. Reaction of Diazonium salts Reaction involving replacement of diazonium group Replacement by – Cl , -Br, -CN: sandmeyer rxn Gettermann reaction: replacement by – Cl , Br: Balz - Schiemann : Replacement by –F .–I ,- H, -OH, -NO2 B. Reactions involving retention of diazonium Group: Coupling reaction

33. Replacement by – Cl , -Br, -CN: sandmeyer rxn Cl

34. 2. Gatterman reactions diazonium groups are replaced with Cl or Br by treating the diazonium salt solution with halogen acid in the presence of copper powder.

35. 3. Replacement of –I Diazonium group may be replaced by iodine by treatment with potassium iodide.

36. 4. The Schiemann reaction the diazonium group is replaced by hydrogen after treatment with mild reducing agents such as hypophosphorous acid (or) ethanol.

37. 5. Replacement of -OH

38. Azo coupling Reaction Benzendiazonium chloride + phenol give p- hydroxyazobenzene .

39. Importance of Diazonium salts Arene diazonium salts are intermediates to introduce –F, - Cl , -Br, -I, -CN, -H, -OH, NO2 groups in aromatic ring. Azo comounds are strongly coloured (red, yellow, orange, blue) and used as dyes.