CONTENT *Basic info. P.3 *Naming convention P.4 *Physical property *Class of amines P57 P.5-7 P.8-18
BASIC INFO. Homologous series Primary alkamine Functional group Class of carbon compounds Amine (Aliphatic / Aromatic) General formula Amino group C n H 2n+1 NH 2
NAMING CONVENTION amino- eg Prefix -amine eg Suffix 2-aminopentane Ethanamine Naming priority w/ carbon compoundsmultiple functional groups: carboxylic acid > ester > amide > aldehyde > ketone > alcohol > amine (lowest priority among these carbon compounds)
PHYSICAL PROPERTY 1) Smell - gaseous s amine: characteristic ammonia smell - liquid amine: characteristic fishy smell 2) Boiling / Melting point - in general: amine w/ C atoms : boiling / melting pt amine w/ C atoms : boiling / melting pt
PHYSICAL PROPERTY 2) Boiling / Melting point (cont d) - boiling / melting pt comparing w/ those of alkanes ( amines: polar; able to form H bonds./. amine molecules) - boiling / melting pt comparing i g w/ those of alcohols l of ~ relative molecular masses ( electronegativity ti it of O > N polarity of O-H bond in alcohols > N-H bond in amines strength of H bond./. alcohols > amines)
PHYSICAL PROPERTY 3) Solubility - solubility of amines w/ no. of C atoms - amine w/ C atoms / of molecular mass hd hydrogen bond forms between bt amine molecules and water molecules - amines w/ C atoms / of molecular mass hydrogen bond CANNOT form between amine molecules and water molecules
1) Aliphatic amines - primary amines: i arise when alkyl replaces 1 of 3 H atoms in ammonia a eg methylamine [ CH 3 NH 2 ] - colourless, has characteristic ammonia smell - arise naturally as the result of putrefaction (ie protein decomposition of body of a dead animal breakdown of cohesion./. tissues + liquefaction of most organs)
eg methylamine (cont d) Production: - CH 3 OH + NH 3 CH 3 NH 2 + H 2 O (methanol + ammonia methylamine + water) Uses: - substrate for methanogenesis (ie formation of methane by microbes) - as a buffering agent in lumen of chloroplast in plants - manufacture some pharmaceuticals (eg ephedrine) / pesticides (eg carbaryl), etc. - scavenging hydrogen sulphide from hydrocarbon in refining applications
1) Aliphatic amines - secondary amines : have 2 alkyl substituents bound to N together w/ 1 H atom eg dimethylamine [ (CH 3 ) 2 NH ] - colourless, has characteristic ammonia smell, colourless, has characteristic ammonia smell, flammable
eg dimethylamine (cont d) Production: - 2 CH 3 OH + NH 3 (CH 3 ) 2 NH + 2 H 2 O (2 methanol + ammonia dimethylamine +2 water) Uses: - manufacture dimethylformamide / dimethylacetamide for production of some agrichemicals (eg dimefox)/ pharmaceuticals (eg diphenhydramine) - make tabun (ie a kind of nerve agent interfering w/ normal functioning of mammalian nervous system)
1) Aliphatic amines - tertiary ti amines : all 3 H atoms are replaced by org substituents eg trimethylamine [ N(CH 3 ) 3 ] - colourless, has characteristic fishy smell, flammable, hygroscopic - responsible for odour often associated w/ halitosis / fouling fish
eg trimethylamine (cont d) Production: - 3 CH 3 OH + NH 3 N(CH 3 ) 3 + 3 H 2 O (3 methanol + ammonia trimethylamine +3 water) Uses: - used in synthesis of choline (a kind of vitamin B)/ used in synthesis of choline (a kind of vitamin B)/ plant hormone / some basic dyes
1) Aliphatic amines - quaternary ammonium salts : +vely charged polyatomic ions of the structure NR 4+ (R = alkyl / aryl group) - can display a range of health effects (eg severe caustic burns on skin / gastro-intestinal lining)
Production: - prepared by quaternization ation (alkylation lation of tertiary amines) eg CH 3 (CH 2 ) n N(CH 3 ) 2 + ClCH 2 C 6 H 5 [CH 3 (CH2) n N(CH 3 ) 2 CH 2 C 6 H 5 ] + Cl - (long-chain alkyldimethylamine + benzyl chloride benzalkonium chloride) Uses: - used as disinfectants / fabric softeners / surfactants / / / / antistatic agents (eg in shampoos)
2) Aromatic amines - amine w/ 1 aromatic substituent ( ie -NH 2 / -NH- / nitrogen group(s) attached to an aromatic hydrocarbon) eg aniline [ C 6 H 5 NH 2 ] - colourless, has characteristic fishy smell, flammable
eg aniline (cont d) Production: Step 1: use conc. mixture of nitric acid + sulphuric acid to nitrate benzene at 50 60 o C Step 2: hydrogenate the resulting nitrobenzene (from Step 1) at 200-300 o C C 6 H 5 NO 2 + 3 H 2 C 6 H 5 NH 2 + 2 H 2 O (nitrobenzene + 3 hydrogen aniline + 2 water)
eg aniline (cont d) Uses: - manufacture precursors to polyurethane / indigo dye / methyl orange (a kind of ph indicator) - manufacture rubber processing materials The end*