Sec 1 STRUCTURE AND PROPERTIES Carbon is sp2 hybridized. 1.32A Bond angles are close to 川、125° 1.23A 124 0.97 120°. ,)1069 1.10 O-H eclipsed with C=O,to H 11100 H get overlap of zorbital bond angles bond lengths with orbital of lone pair or. Copyright2010 Pearson Prentice Hall,Inc oxygen. Resonance Stabilization R-C-0-H+H,0:→ +H,0+ pK=5 (K≡10-) acid carboxylate
Carbon is sp2 hybridized. Bond angles are close to 120. O-H eclipsed with C=O, to get overlap of orbital with orbital of lone pair on oxygen. Resonance Stabilization Sec 1 STRUCTURE AND PROPERTIES
Resonance Structures 可 :0: :0: H←→ H一 H H H 01 major very minor minor H H CH3 H
Resonance Structures
B.P Higher boiling points than similar alcohols,due to dimer formation bp.°C Formaldehyde -21° Methanol 64° Formic acid 100P Acetaldehyde 21° Ethanol 78 Acetic acid 118 0H-0 R- C- Acetic acid,b.p.118C hydrogen-bonded acid dimer
B.P Higher boiling points than similar alcohols, due to dimer formation Acetic acid, b.p. 118C
Melting Points Aliphatic acids with more than 8 carbons are solids at room temperature. Double bonds (especially cis)lower the melting point.Note these 18-C acids: ●Stearic acid(saturated):72c硬脂酸 ●Oleic acid(one cis double bond):l6C油酸 ●Linoleic acid(two cis double bonds):-5c亚油酸 COOH COOH stearic acid,mp 70C oleic acid,mp 4C
Melting Points Aliphatic acids with more than 8 carbons are solids at room temperature. Double bonds (especially cis) lower the melting point. Note these 18-C acids: Stearic acid (saturated): 72 C硬脂酸 Oleic acid (one cis double bond): 16 C油酸 Linoleic acid (two cis double bonds): -5 C亚油酸 硬脂酸,油酸,亚油酸
Solubility Water solubility decreases with the length of the carbon chain. Up to 4 carbons,acid is miscible in water. More soluble in alcohol. Also soluble in relatively nonpolar solvents like chloroform because it dissolves as a dimer
Solubility Water solubility decreases with the length of the carbon chain. Up to 4 carbons, acid is miscible in water. More soluble in alcohol. Also soluble in relatively nonpolar solvents like chloroform because it dissolves as a dimer