西北农林科技大学：《有机化学 Organic chemistry》课程教学课件（2012）Chapter 21 Carboxylic Acids

0光不动大太好 招华院 Organic Chemistry,6th Edition L.G.Wade,Jr. Chapter 21 Carboxylic Acids By Junru Wang Email:wangjr07@163.com

By Junru Wang Email: wangjr07@163.com Chapter 21 Carboxylic Acids Organic Chemistry, 6th Edition L. G. Wade, Jr

CONTENT ■REVIEW:NAMING USTRUCTURE AND PROPERTIES NUCLEOPHILIC SUBSTITUTION ■PREPARATIONS ■REACTIONS ■ENOLATE REACTIONS

CONTENT REVIEW：NAMING STRUCTURE AND PROPERTIES NUCLEOPHILIC SUBSTITUTION PREPARATIONS REACTIONS ENOLATE REACTIONS

IUPAC Nomenclature -Review Many aliphatic acids have historical names. IUPAC names:drop the -e from the parent alkane and add the suffix -oic acid if the compound contains a carbon-carbon double bond,change the infix -an-to -en- COOH COOH COOH CeHs Propenoic acid trans-2-Butenoic acid trans-3-Phenyl- (Acrylic acid) (Crotonic acid) propenoic acid (Cinnamic acid)

IUPAC Nomenclature -Review Many aliphatic acids have historical names. IUPAC names: drop the -e from the e parent alkane and add the suffix -oicacid if the compound contains a carbon-carbon double bond, change the infix -an-to -en￾Propenoic acid (Acrylic acid) trans-3-Phenyl￾propenoic acid (Cinnamic acid) trans-2-Butenoic acid (Crotonic acid) COOH C 6 H 5 COOH COOH

IUPAC Nomenclature -Review ■Dicarboxylic acids: add the suffix -dioic acid to the name of the parent alkane containing both carboxyl groups 0 Ethanedioic acid Propanedioic acid (Oxalic acid) (Malonic acid) HO. H Butanedioic acid Pentanedioic acid Hexanedioic acid (Succinic acid) (Glutaric acid) (Adipic acid)

IUPAC Nomenclature -Review Dicarboxylic acids: add the suffix -dioicacidto the name of the parent alkane containing both carboxyl groups HO OH O Propanedioic acid (Malonic acid) Ethanedioic acid (Oxalic acid) O HO OH O O Hexanedioic acid (Adipic acid) Pentanedioic acid (Glutaric acid) Butanedioic acid (Succinic acid) O OH O HO OH O HO O HO OH O O

IUPAC Nomenclature -Review if the carboxyl group is attached to a ring,name the ring compound and add the suffix -carboxylic acid 1COOH 3 2-Cyclohexene- trans-1,3-Cyclopentane- carboxylic acid dicarboxylic acid COOH CH(CH3) 2-isopropylcyclopentane- carboxylic acid

IUPAC Nomenclature -Review if the carboxyl group is attached to a ring, name the ring compound and add the suffix -carboxylic acid 3 2 1 2-Cyclohexene￾carboxylic acid trans-1,3-Cyclopentane- dicarboxylic acid COOH HOOC COOH COOH CH(CH 3 ) 2 2-isopropylcyclopentane￾carboxylic acid

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. 118C

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