《有机化学》课程PPT教学课件（Official PPT of Organic Chemistry, 7th Edition, L. G. Wade, Jr.Pearson Education）Chapter 18 Ketones and Aldehydes

Organic Chemistry,7th Edition L.G.Wade,Jr. Chapter 18 Ketones and Aldehydes Copyright 2010 Pearson Education,Inc

Chapter 18 Copyright © 2010 Pearson Education, Inc. Organic Chemistry, 7th Edition L. G. Wade, Jr. Ketones and Aldehydes

Carbonyl Compounds TABLE 18-1 Common Classes of Carbonyl Compounds Class General Formula Class General Formula ketones R-C-R aldehydes R-C-H carboxylic acids C-OH acid chlorides R-C-CI esters R-C-O-R amides R NH Copyright2010 Pearson Prentice Hall,Inc. Chapter 18 2

Chapter 18 2 Carbonyl Compounds

Carbonyl Structure length energy ketone C=O bond 1.23A 745 kJ/mol (178 kcal/mol alkene C=C bond 1.34A 611 kJ/mol (146 kcal/mol) Copyright 2010 Pearson Prentice Hall,Inc. Carbon is sp2 hybridized. C-O bond is shorter,stronger,and more polar than C=C bond in alkenes. Chapter 18 3

Chapter 18 3 Carbonyl Structure ▪ Carbon is sp2 hybridized. ▪ C═O bond is shorter, stronger, and more polar than C═C bond in alkenes

Ketone Nomenclature 3 4 in-chom 2 2 CH3 CH3 3-methyl-2-butanone 4-hydroxy-3-methyl-2-butanone -Number the chain so that carbonyl carbon has the lowest number. Replace the alkane -e with -one. Chapter 18 4

Chapter 18 4 Ketone Nomenclature ▪ Number the chain so that carbonyl carbon has the lowest number. ▪ Replace the alkane -e with -one. 3-methyl-2-butanone 4-hydroxy-3-methyl-2-butanone CH3 C O CH CH3 CH3 CH3 C O CH CH3 CH2OH 1 2 3 4 1 2 3 4

Ketone Nomenclature (Continued) 3-bromocyclohexanone 3 Br For cyclic ketones,the carbonyl carbon is assigned the number 1. Chapter 18 5

Chapter 18 5 Ketone Nomenclature (Continued) ▪ For cyclic ketones, the carbonyl carbon is assigned the number 1. 3-bromocyclohexanone O Br 1 3

Aldehydes Nomenclature 3 3-methylpentanal The aldehyde carbon is number 1. IUPAC:Replace -e with -al. Chapter 18 6

Chapter 18 6 CH3 CH2 CH CH3 CH2 C H O Aldehydes Nomenclature ▪ The aldehyde carbon is number 1. ▪ IUPAC: Replace -e with -al. 3-methylpentanal 1 2 3 5

Carbonyl as Substituent -On a molecule with a higher priority functional group,a ketone is an oxo and an aldehyde is a formyl group. Aldehydes have a higher priority than ketones. COOH 9 CH3 CH3-C-CH-CH2-C-H 43 CHO 3-methyl-4-oxopentanal 3-formylbenzoic acid Chapter 18

Chapter 18 7 Carbonyl as Substituent ▪ On a molecule with a higher priority functional group, a ketone is an oxo and an aldehyde is a formyl group. ▪ Aldehydes have a higher priority than ketones. 3-methyl-4-oxopentanal 3-formylbenzoic acid 4 3 1 1 3 CH3 C CH CH3 CH2 C H O O COOH CHO

Common Names for Ketones Named as alkyl attachments to-C=O. Use Greek letters instead of numbers. O CH3-C-CH-CH3 CH3CH-C-CH-CH3 CH3 Br CH3 methyl isopropyl ketone a-bromoethyl isopropyl ketone Chapter 18 8

Chapter 18 8 Common Names for Ketones ▪ Named as alkyl attachments to —C═O. ▪ Use Greek letters instead of numbers. methyl isopropyl ketone a-bromoethyl isopropyl ketone CH3 C O CH CH3 CH3 CH3CH C O CH CH3 CH3 Br

Historical Common Names 0 >CH; acetone acetophenone benzophenone Chapter 18 9

Chapter 18 9 Historical Common Names CH3 C O CH3 C CH3 O C O acetone acetophenone benzophenone

Boiling Points CH.CH,CH,CH, CH一O一CHCH CH,CH2一C一H CH,- C一CH CH,CH,CH2一OH butane methoxyethane propanal acetone I-propanol bp0℃ bp 8C bp 49 C bp 56C bp 97C Copyright2010 Pearson Prentice Hall,Inc. Ketones and aldehydes are more polar,so they have a higher boiling point than comparable alkanes or ethers. They cannot hydrogen-bond to each other,so their boiling point is lower than comparable alcohol. Chapter 18 10

Chapter 18 10 Boiling Points ▪ Ketones and aldehydes are more polar, so they have a higher boiling point than comparable alkanes or ethers. ▪ They cannot hydrogen-bond to each other, so their boiling point is lower than comparable alcohol