INTHENAMEOFALLAHTHEMOSTGRACIOUS,THEMOSTMERCIFUL

CHEM122.LEVEL-2LECTURE#15

ALDEHYDES&KETONES-Chapter12

ChemistrybyTimberlakeP-377

Presentedby:DepartmentOfChemistryFEBRUARY-2007

RCDP-R.1Aldehydes,andKetones-CONTENTAldehydesandKetonesIUPAC-NamingofAldehydes&KetonesAldehydesasFlavoringKetonesasHormonesPropertiesofAldehydes&Ketones2P-3573

AldehydesandKetones

4AldehydesandKetonesP-377Inanaldehyde,anHatomisattachedtoacarbonylgroup

O carbonylgroup

|| CH3-C-HInaketone,twocarbongroupsareattachedtoacarbonylgroup

O carbonylgroup

|| CH3-C-CH35NamingofAldehyde-p379

IntheIUPACsystem,theeofthealkanenameisreplacedwithal.

Aldehyde commonname IUPACname

HCHO Formaldehyde Methanal

CH3CHO Acetaldehyde EthanalCH3CH2CHO Propionaldehyde Propanal CH3(CH2)2CHO n-Butyraldehyde n-Butanal3-Methylbutanal3-Methylbutanal6

GlucoseisanaldehydeP-3877AldehydesasFlavoringsP-3838NamingKetonesP-378IntheIUPACname,the-einthealkanenameisreplacedwith-oneInthecommonname,addthewordketoneafternamingthealkylgroupsattachedtothecarbonylgroup

O

O

|| || CH3-C-CH3 CH3-C-CH2-CH3

Propanone 2-Butanone

(Dimethylketone)(Ethylmethylketone)9NamingofKetones

IntheIUPACsystem,the-eofthealkanenameisreplacedwith–one.

Ketone commonname IUPACname

CH3COCH3 Acetone Propanone CH3COCH2CH3 EthylmethylketoneButanone CH3CO(CH2)2CH3Methylpropylketone2-Pentanone CH3CH2COCH2CH3Diethylketone 3-Pentanone

3-Methyl-2-butanone

123410NamingofKetone11FructoseisaKetone

12KetonesP-383 OO

||||Butterflavor CH3-C-C-CH3 butanedione O

||Cloveflavor CH3-C-CH2CH2CH2CH2CH3

2-heptanone

13SomeimportantAldehydesandKetonesGlyceraldehydes14HormonesasKetones15HormonesoftheSteroidfamily16Question#1

Classifyeachasanaldehyde(1),ketone(2)orneither(3).O || A.CH3CH2CCH3 B.CH3-O-CH3 CH3O

||

C.CH3-C-CH2CH D. CH317Solution#1

Classifyeachasanaldehyde(1),ketone(2)orneither(3).O || A.CH3CH2CCH3

2

B.CH3-O-CH33

CH3O || C.CH3-C-CH2CH1 D. 2

CH318Question#2Namethefollowing O ||A.CH3CH2CCH3 B.

CH3O

||

C.CH3-C-CH2CH

CH319Solution#2 O ||A.CH3CH2CCH3 B.2-butanone(ethylmethylketone)

cyclohexanoneCH3O

||

C.CH3-C-CH2CH CH32,2-dimethylbutanal 20Question#3Drawthestructuralformulasforeach:A.3-MethylpentanalB.2,3-DichloropropanalC.3-Methyl-2-butanone21Solution#3Drawthestructuralformulasforeach:

CH3 O ||

A.3-Methylpentanal CH3CHCHCH2CH ClO ||B.2,3-Dichloropropanal Cl-CH2CHCHO

||C.3-Methyl-2-butanone CH3CHCCH3

CH3

22PropertiesofAldehydesandKetonesP-385I-BoilingPoints

Theboilingpointofaldehydeandketoneishigherthanalkanesandetherduetopolarityofcarbonylgroup,whichcausesdipole-dipoleinteractionbetweenmoleculesofaldehydeandketone.

δ+δ-δ+δ-δ+δ-23II-SolubilityofAldehydeandKetoneinwater

P-385

AldehydesandKetonesdonotmakehydrogenbondwitheachother.

But,electronegativeoxygenatomdoeshydrogenbondwithwatermolecule. -CarbonylcompoundswithC1-C4carbonsareverysolubleinwater.-C5andhighercarbonylcompoundsarelesssolubleinwaterasnonpolaralkylgroupdiminishespolarityofmolecule.24

INTHENAMEOFALLAHTHEMOSTGRACIOUS,THEMOSTMERCIFUL

CHEM122.LEVEL-2LECTURE#16

CarboxylicAcidsAndEstersChapter13

ChemistrybyTimberlakeP-408

Presentedby:

RCDP-R.DepartmentOfChemistryAPRIL-2007.25CarboxylicAcids&EstersCONTENTSNaming&PropertiesofCarboxylicAcids,EstersEsterificationandHydrolysis26CarboxylGroupP-410

Carboxylicacidscontainthecarboxylgrouponcarbon1.

O

CH3—

C—OH

=

CH3—COOH

carboxylgroup27CarboxylicAcids

Compoundscontainingacarbonylgroup(C=O)whichisdirectlyattachedtoahydroxylgroup(OH)arecalledcarboxylicacids.StructureHybridization=sp2bondangles=1200Configuration=planarR=AliphaticorAromatic28Classificationofcarboxylicacids:

1)AliphaticAcid

2)Aromaticacids

R-COOHAr-COOH (R=anyalkylgroup)(Ar=Arylgroup)

Namesandnaturalsources

Carboxylic IUPAC Common Sources acids name name HCOOH Methanoicacid Formicacid Ant,beesting

CH3COOHEthanoicacid Aceticacid Vinegar

CH3CH2COOHPropanoicacidPropionicacid Dairyproducts

CH3(CH2)2COOHButanoicacid Butyricacid Rancidbutter

29NumberingandNaminginCarboxylicAcidα,β-Dimethylbutyricacidδγβα

δ-Hydroxyvalericacid30NamingRulesP-410Identifylongestchain(IUPAC)Numbercarboxylcarbonas1(Common)Assign,,γtocarbonatomsadjacenttocarboxylcarbon

CH3| CH3—

CH—CH2—COOH

IUPAC3-methylbutanoicacid Common-methylbutryicacid31

NamingCarboxylicAcidsP-411Formula IUPAC Common

alkan-oicacid

prefix–icacidHCOOH methanoicacid

formicacidCH3COOH ethanoicacid

aceticacidCH3CH2COOH propanoicacid

propionicacid

CH3CH2CH2COOHbutanoicacid

butyricacid

32Question#1GiveIUPACandcommonnames:A.CH3COOH

CH3

|B.CH3CHCOOH33Solution#1A.CH3COOH

ethanoicacid;aceticacid

CH3

|B.CH3CHCOOH 2-methylpropanoicacid;

-methylpropionicacid

34PhysicalPropertiesofCarboxylicAcidP-413Carboxylicacidsarepolarcompoundandtheymayexistasdimers.

1-BoilingPoints Carboxylicacidshavehigherboilingpointthanalcohols,ketonesandaldehydesofsimilarmassduetoexistenceofdimers.

Example

Propanal 1-Propanol Aceticacidmolarmass 58 60 60

b.p. 490C 970C 1180CDIMER35

2-SolubilityP414

Carboxylicacidswithonetofourcarbonsareverysolubleinwater,becauseofHdrogenbonding---withwatermolecules.

36ChemicalProperties

1-AcidityofCarboxylicacids

P415-6

CarboxylicacidsareweakacidsCH3COOH+H2O CH3COO–+H3O+Carboxylicacidsareweakacidsastheyionizeinwatertogiveacidicsolution(carboxylateanionandhydroniumion).

Carboxylicacidsarebetteracidsthanphenolsandalcohols.

Acidity:RCOOH>ArOH>ROHcarboxylicacidsphenolsalcohols37

2-NeutralizationofCarboxylicAcidswithbases:

CarboxylicacidreactswithbasessuchasNaOH,KOHandNaHCO3toproducesaltandwater.

CH3COOH+NaOH CH3COO–Na++H2O383-Esterification

P-418

ReactionofacarboxylicacidandalcoholProductsareesters+waterAcidcatalyst

O

H+ CH3—

C—OH+HO—CH2CH3

O

CH3—

C—

O—CH2CH3

+

H2O393-FormationofEstersP-418Inester,theHinthecarboxylgroupisreplacedwithanalkylgroupO

CH3—

C—O—CH3 =CH3—COO—CH3

estergroup40

EstersinPlantsP-420

Estersgiveflowersandfruitstheirpleasantfragancesandflavors.41

EstersinPlants

Manyofthefragrancesofperfumesandflowersandtheflavorsoffruitsareduetoesters.Smallestersarevolatilesowecansmellthemandsolubleinwatersowecantastethem. Somenaturallyoccurringestersinfruitsandflavorings Esters (flavor/odor)

Propylethanoate pears Pentylethanoate banana Octylethanoate oranges Ethylbutanoate pineapples42NamingEstersP-419

Namethealkylfromthealcohol–O-NametheacidwiththeC=Owith–ateacid alcohol

O

methyl CH3—

C—O

—CH3Ethanoatemethylethanoate(IUPAC)(acetate) methylacetate(common)43SomeEstersandTheirNamesP-419Flavor/OdorRaspberries HCOOCH2CH3

ethylmethanoate(IUPAC) ethylformate(common)Pineapples CH3CH2CH2COOCH2CH3

ethylbutanoate(IUPAC) ethylbutyrate(common)44NamingEsters

Esters(RCOOR)consistsofanacyl(RCO)partfromtheacidand–ORfromthealcohol.45NamingEsters

Examples

46Question2

GivetheIUPACandcommonnamesofthefollowingcompound,whichisresponsiblefortheflavorandodorofpears.

O

CH3—

C—O

—CH2CH2CH3

47Solution2

Omethyl propyl CH3—

C—O—CH2CH2CH3

propylethanoate(IUPAC) propylacetate(common)48Question3Drawthestructureofthefollowingcompounds:3-bromobutanoicacidEthylpropionoate49Solution3A.3-bromobutanoicacid

Br

|CH3CHCH2COOHB. Ethylpropionoate O

CH3CH2COCH2CH3OR

CH3CH2COOCH2CH350ESTERS

Estersarederivativesofcarboxylicacidsinwhichanalkoxygroup(-OR)replacesthehydroxyl(-OH)groupinthecarboxylicacids.

CarboxylicAcid

Preparationby

Esterification

Carboxylicacidreactswithanalcoholwhenheatedinthepresenceofanacidcatalyst(H2SO4)togiveanester.51

Esterification

Examples52Chemicalproperties

1-HydrolysisP-423EstersreactwithwaterandacidcatalystSplitintocarboxylicacidandalcohol

O

H+ H

—

C—O—CH2CH3+

H2OO

H

—

C—OH+HO—CH2CH353A-AcidHydrolysisofEsters54

B-BasecatalyzedHydrolysisofEsters

(Saponification)

WhenanesterundergoeshydrolysiswithstrongbasesuchasNaOH,KOH,theproductsarealcoholandsaltofanacid.

55SaponificationP-424EstersreactwithbasesProducethesaltofthecarboxylicacidandalcohol

O

CH3C—OCH2CH3+

NaOH O

CH3C—O–Na++HOCH2CH3

saltofcarboxylicacid56SaponificationBasichydrolysisofestersisalsoknownassaponification.

Inindustry:Naturaloil(triglycerides)arehydrolyzedtogiveglycerinandsodiumsaltoffattyacidswhichisknownassoap.

Oil(TAG)+NaOHSoap+Glycerin57Question4

Writetheequationforthereactionofpropionicacidandmethylalcoholinthepresenceofanacidcatalyst.

58Solution4 O

H+CH3CH2COH+HOCH3O

CH3CH2COCH3+H2O59α

HealthNote-