logging in or signing up amines reactions (1) salaar Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 30 Category: Science & Tech.. License: All Rights Reserved Like it (0) Dislike it (0) Added: October 13, 2011 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Slide 1: Amines, reactions Amines are similar to ammonia in their reactions. Like ammonia, amines are basic . Like ammonia, amines are nucleophilic and react with alkyl halides, acid chlorides, and carbonyl compounds. The aromatic amines are highly reactive in electrophilic aromatic substitution.Slide 2: Amine, reactions: As bases Alkylation Reductive amination Conversion into amides EAS Hofmann elimination from quarternary ammonium salts Reactions with nitrous acidSlide 3: As bases a) with acids b) relative base strength c) Kb d) effect of groups on base strengthSlide 4: with acidsSlide 5: relative base strength RNH 2 > NH 3 > ArNH 2 K b ionization of the base in water :Base + H 2 O H:Base + + OH - K b = [ H:Base + ] [ OH - ] / [ :Base ] K b aliphatic amines 10 -3 – 10 -4 ammonia 1.8 x 10 -5 anilines 10 -9 or lessSlide 6: Why are aliphatic amines more basic than ammonia? NH 3 + H 2 O NH 4 + + OH - R-NH 2 + H 2 O R-NH 3 + + OH - The alkyl group, -R, is an electron donating group. The donation of electrons helps to stabilize the ammonium ion by decreasing the positive charge, lowering the ΔH, shifting the ionization farther to the right and increasing the basicity.Slide 7: Why are aromatic amines less basic than aliphatic amines? R-NH 2 + H 2 O R-NH 3 + + OH - resonance stabilization of the free base, increases the ΔH, shifts the ionization to the left, decreasing base strength.Slide 8: Effect of substituent groups on base strength : Electron donating groups will stabilize the anilinium ion, decreasing the ΔH, shifting the ionization farther to the right and making the compound a stronger base . Electron withdrawing groups destabilize the anilinium ion, increasing the ΔH, shifting the ionization towards the reactants, making the compound a weaker base .Slide 9: Common substituent groups: -NH 2 , -NHR, -NR 2 -OH -OR -NHCOCH 3 electron donating -C 6 H 5 groups -R -H -X -CHO, -COR -SO 3 H electron withdrawing -COOH, -COOR groups -CN -NR 3 + -NO 2Slide 10: Number the following in decreasing order of base strength (let #1 = most basic, etc. 4 1 5 3 2Slide 11: 2. Alkylation (ammonolysis of alkyl halides)Slide 13: 3. Reductive aminationSlide 15: Conversion into amides R-NH 2 + RCOCl RCONHR + HCl 1 o N -subst. amide R 2 NH + RCOCl RCONR 2 + HCl 2 o N,N -disubst. amide R 3 N + RCOCl NR 3 oSlide 17: Conversion into sulfonamides R-NH 2 + ArSO 2 Cl ArSO2NHR + HCl 1 o N -subst.sulfonamide R 2 NH + ArSO 2 Cl ArSO 2 NR 2 + HCl 2 o N,N -disubst.sufonamide R 3 N + ArSO 2 Cl NRSlide 18: Schotten-Baumann technique: reactions of aromatic acid chlorides are sped up by the addition of base. R-NH 2 + ArSO 2 Cl + KOH ArSO2N H R 1 o acidic ArSO 2 NR water soluble salt R 2 NH + ArSO 2 Cl + KOH ArSO 2 NR 2 + HCl 2 o N,N -disubst.sufonamide water insolubleSlide 19: Hinsberg Test: unknown amine + benzenesulfonyl chloride, KOH (aq) Reacts to produce a clear solution and then gives a ppt upon acidification primary amine . Reacts to produce a ppt secondary amine . Doesn’t react tertiary amine .Slide 21: sulfanilamide “magic bullet” antibioticSlide 23: EAS -NH 2 , -NHR, -NR 2 are powerful activating groups and ortho/para directors a) nitration b) sulfonation c) halogenation d) Friedel-Crafts alkylation e) Friedel-Crafts acylation f) coupling with diazonium salts g) nitrosationSlide 24: a) nitrationSlide 25: b) sulfonationSlide 26: c) halogenationSlide 27: Swimming pool test kit for chlorine:Slide 28: Friedel-Crafts alkylation NR with –NH 2 , -NHR, -NR 2Slide 29: Friedel-Crafts acylation NR with –NH 2 , -NHR, -NR 2Slide 30: g) nitrosationSlide 31: h) coupling with diazonium salts azo dyesSlide 32: Hofmann elimination from quarternary hydroxides step 1, exhaustive methylation 4 o salt step 2, reaction with Ag 2 O 4 o hydroxide + AgX step 3, heat to eliminate alkene(s) + R 3 NSlide 34: 7. Reactions with nitrous acidSlide 35: note: 90% of all tested nitrosamines are carcinogenic in man. Many nitrosamine cancers are organ specific. For example, dimethylnitrosamine causes liver cancer while the nitrosamines in tobacco smoke cause lung cancer. Sodium nitrite (“cure”) is used as a preservative in meats such as bacon, bologna, hot dogs, etc. to kill the organism responsible for botulism poisoning. In the stomach, the nitrous acid produced from sodium nitrite can react with secondary and tertiary amines to form nitrosamines. To reduce the formation of nitrosamines, ascorbic acid (Vitamin C) is now added to foods cured with sodium nitrite. Nitrosamines are also found in beer!Slide 36: Amines, reactions Amines are similar to ammonia in their reactions. Like ammonia, amines are basic . Like ammonia, amines are nucleophilic and react with alkyl halides, acid chlorides, and carbonyl compounds. The aromatic amines are highly reactive in electrophilic aromatic substitution.Slide 37: Amine, reactions: As bases Alkylation Reductive amination Conversion into amides EAS Hofmann elimination from quarternary ammonium salts Reactions with nitrous acid You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.