Compound containing nitrogen
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Nitro compounds can be prepared by several methods including nitration of alkanes, from alkyl halides, and from primary amines. Nitro compounds undergo various reactions including reduction, hydrolysis, halogenation, and reaction with nitrous acid. Amines can be prepared from alkyl halides, oximes, alkyl cyanides, amides, and nitro compounds by reduction. Amines undergo reactions like basic hydrolysis, reactions with nitrous acid to form diazonium salts, acylation, and electrophilic aromatic substitution. Diazonium salts are important intermediates that allow introduction of groups like chlorine, bromine, fluoride, and hydroxyl into aromatic rings. They also undergo azo coupling reactions
![a. From oximes
• Aldoxime or ketoximes are reduce by
sodium and ethanol to primary amine.
• R- CH= N-OH + 4[H] → R-CH2-NH2 + H2O
• Ketoxime.
• Acetaloxime.](https://image.slidesharecdn.com/70nnekcprzkmqrjvxmjk-signature-016162306cab773303228479b063befdf29baf20ea52f9a91b002e88ad5a07bd-poli-151129105602-lva1-app6891/85/Compound-containing-nitrogen-17-320.jpg)
![b. From alkyl cyanide(alkyl nitriles)
• Alkyl cyanide on reduction by Na and
ethanol give primary amine.
• R-C ≡ N + 4[H] → R-CH2-NH2
• Eg. Acetonitrile and Propanenitrile.](https://image.slidesharecdn.com/70nnekcprzkmqrjvxmjk-signature-016162306cab773303228479b063befdf29baf20ea52f9a91b002e88ad5a07bd-poli-151129105602-lva1-app6891/85/Compound-containing-nitrogen-18-320.jpg)
![c. From amides
4[H]](https://image.slidesharecdn.com/70nnekcprzkmqrjvxmjk-signature-016162306cab773303228479b063befdf29baf20ea52f9a91b002e88ad5a07bd-poli-151129105602-lva1-app6891/85/Compound-containing-nitrogen-19-320.jpg)
![d. From nitro compound
• Nitro compounds are reduced by
tin(Sn) or iron and con HCl to
corresponding primary amines.
• R- NO2 + 6[H] → R- NH2 + 2H2O
• Eg. Nitrobenzene.
• Nitropropane.](https://image.slidesharecdn.com/70nnekcprzkmqrjvxmjk-signature-016162306cab773303228479b063befdf29baf20ea52f9a91b002e88ad5a07bd-poli-151129105602-lva1-app6891/85/Compound-containing-nitrogen-20-320.jpg)
![• Primary amine: (HNO2) eg. Aniline
R – NH2 + NaNO2 + 2HCl → [ R- N2
+Cl-] + NaCl + 2H2O
Alkyl diazonium chloride
• Secondary amine: (HNO2)eg. diethylamine
R2 – NH + NaNO2 + HCl → R2N-N=O + NaCl + 2H2O
N- nitroso dialkylamine
• Tertiary amine: (HNO2)eg. triethylamine
R3 – N + NaNO2 + HCl → [ R3- NH]+NO2
- + NaCl
trialkyl ammonium nitrate
2. Action of nitrous acid](https://image.slidesharecdn.com/70nnekcprzkmqrjvxmjk-signature-016162306cab773303228479b063befdf29baf20ea52f9a91b002e88ad5a07bd-poli-151129105602-lva1-app6891/85/Compound-containing-nitrogen-25-320.jpg)
Compound containing nitrogen
- 1. Compound containing Nitrogen By Azeem
- 2. Nitro Compound General method of preparation- 1. Nitration of alkanes 2. From alkyl halides 3. From salts of α-halogeno carboxylic acid 4. From primary amines 5. From a-nitroalkenes(2methyl nitropropene) 6. From oximes(aldoxime +O in trifluoroperoxy acetic acid)
- 3. Reaction of nitroalkane 1. Reduction 2. Hydrolysis 3. Halogenation 4. Reaction with nitrous acid 5. Condensation with aldehydes and ketones Nitro Compound
- 7. 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.
- 8. • Both amine and ammonia are produce basic aqueous solution. • Amine and ammonia are weak base due to accepter of proton. • NH3 + H2O → NH4 + OH • Increase mass decrease solubility. Colourless. Physical Properties of Amines
- 13. Method of preparation of amines 1. From alkyl halide: by ammonolysis 2. From alkyl halide: Gabriel phthalimide synthesis(alkylation of phthalimide) 3. From oximes, alkyl cyanides, amides and nitro compounds: by reduction (a) From oximes (b) From alkyl cyanide(alkyl nitriles) (c) From amides (d) From nitro compounds (e) From amides: by hoffman bromamide degradation
- 14. 1. From alkyl halide: by ammonolysis H-NH2 100˚C under pressure
- 15. 2. From alkyl halide: Gabriel phthalimide synthesis
- 16. 3. From oximes, alkyl cyanides, amides and nitro compounds: by reduction
- 17. a. From oximes • Aldoxime or ketoximes are reduce by sodium and ethanol to primary amine. • R- CH= N-OH + 4[H] → R-CH2-NH2 + H2O • Ketoxime. • Acetaloxime.
- 18. b. From alkyl cyanide(alkyl nitriles) • Alkyl cyanide on reduction by Na and ethanol give primary amine. • R-C ≡ N + 4[H] → R-CH2-NH2 • Eg. Acetonitrile and Propanenitrile.
- 20. d. From nitro compound • Nitro compounds are reduced by tin(Sn) or iron and con HCl to corresponding primary amines. • R- NO2 + 6[H] → R- NH2 + 2H2O • Eg. Nitrobenzene. • Nitropropane.
- 21. e. Hoffman bromamide degradation
- 22. Reaction of Amines 1. Basic nature of amines 2. Action of nitrous acid (1⁰ amine, 2⁰ amine, 3⁰ amine) 3. Acylation of amines 4. Alkylation of amines: Hoffmann's exhaustive alkylation 5. Hoffmann elimination 6. Hoffmann’s carbylamines test/ isocyanides test 7. Reaction with arylsulphonyl chloride: Hinsberg’s test 8. Electrophilic aromatic substitution a) Bromination b) Nitration c) sulphonation
- 23. 1. Basic nature of amines • R- NH2 + H+X → R-NH3 +X- ammonium salts • R-NH3 +X- + NaOH → R-NH2 + NaX + H2O • This shows that the reaction is reversible. • C2H5-NH2 + HCl <==> C2H5-NH3 +Cl- Ethylamine ethyl ammonium chloride Aqueous solutions amines are basic, and they turn red litmus paper blue. R-NH2 + H-O-H R- NH3 + + OH- Weak base strongerbase
- 24. 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. • NaNO2 + HCl → NaCl + HNO2 • Except methyl and ethylamine, all primary amine give aliphatic diazonium salt.
- 25. • Primary amine: (HNO2) eg. Aniline R – NH2 + NaNO2 + 2HCl → [ R- N2 +Cl-] + NaCl + 2H2O Alkyl diazonium chloride • Secondary amine: (HNO2)eg. diethylamine R2 – NH + NaNO2 + HCl → R2N-N=O + NaCl + 2H2O N- nitroso dialkylamine • Tertiary amine: (HNO2)eg. triethylamine R3 – N + NaNO2 + HCl → [ R3- NH]+NO2 - + NaCl trialkyl ammonium nitrate 2. Action of nitrous acid
- 26. 3. Acylation of amines • Amine react with acyl chloride in presence of pyridine. • R- NH2 + X-CO-R R- NH – CO –R + HX • Eg. Ethylamine • Silimalary reaction in acetic anhydride, • R- NH2 + (CH3- CO-)2OR-NH-CO-CH3 + CH3- COOH Amines ethanoic anhydride alkyl acetamide • Eg. Aniline
- 27. 4. Alkylation of amines: Hoffmann's exhaustive alkylation • R- NH2 R2NH R3N R4N+X- » 2⁰ amine 3⁰ tetraalkyl ammonium halide • Eg. Methylamine • Eg. Dimethanamine • Eg. N,N- dimethyl aniline RXRX RX
- 28. 5. Hoffmann elimination • Tetra alkyl ammonium halide on heating with moist Ag2O 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. • C2H5N-(CH3)3 +I- + AgOH C2H5-N+(CH3)3OH- + AgI Ethyltrimethyl ammonium iodide • C2H5-N+(CH3)3OH- CH2=CH2 + (CH3)3N + H2O Ethyltrimethyl ammonium hydroxide
- 29. 6. Hoffmann’s carbylamines test/ isocyanides test • R-NH2 + CHCl3 + 3KOH → R- NC + 3KCl + 3H2O • Eg. Ethylamine • and aniline.
- 30. 7. Reaction with arylsulphonyl chloride: Hinsberg’s test
- 31. 8. Electrophilic aromatic substitution • Bromination
- 32. Bromination
- 33. Nitration
- 34. Nitration • Aniline on acetylation on heating 298K.
- 35. Sulphonation
- 36. Preparation of Diazonium Salt’s
- 37. Reaction of Diazonium salts A. Reaction involving replacement of diazonium group 1. Replacement by –Cl, -Br, -CN: sandmeyer rxn 2. Gettermann reaction: replacement by –Cl, Br: 3. Balz- Schiemann: Replacement by –F.–I,-H, - OH, -NO2 B. Reactions involving retention of diazonium Group: Coupling reaction
- 38. Replacement by –Cl, -Br, -CN: sandmeyer rxn Cl
- 39. 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.
- 40. 3. Replacement of –I • Diazonium group may be replaced by iodine by treatment with potassium iodide.
- 41. 4. The Schiemann reaction the diazonium group is replaced by hydrogen after treatment with mild reducing agents such as hypophosphorous acid (or) ethanol.
- 42. 5. Replacement of -OH
- 43. Azo coupling Reaction Benzendiazonium chloride + phenol give p- hydroxyazobenzene.
- 44. 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.