CHAPTER 11CHAPTER 11BONDING AND MOLECULAR BONDING AND MOLECULAR

STRUCTURE:STRUCTURE:

ORGANIC CHEMISTRYORGANIC CHEMISTRYAll bold numbered problemsAll bold numbered problems..

OverviewOverview• Organic chemistry is the study of Organic chemistry is the study of

compounds containing carbon combined compounds containing carbon combined with other non-metals. with other non-metals.

• Bonding plays a critical role in Bonding plays a critical role in understanding the reactivity of these understanding the reactivity of these compounds. compounds.

• These compounds are referred to as These compounds are referred to as hydrocarbons since they are primarily hydrocarbons since they are primarily hydrogen and carbon. hydrogen and carbon.

OverviewOverview

OverviewOverview• Carbon uses spCarbon uses sp33, sp, sp22, and sp , and sp

hybridization in forming the four hybridization in forming the four bonds per carbon atom common to bonds per carbon atom common to almost all carbon compounds. almost all carbon compounds.

• With sp hybridization, there are two With sp hybridization, there are two (2) (2) bonds and 1 bonds and 1 bonds. bonds.

• With spWith sp22 hybridization there is one (1) hybridization there is one (1) bond and 1 bond and 1 bonds. bonds.

Why CarbonWhy Carbon

sp3, sp2, and sp hybridizationsp3, sp2, and sp hybridization

Allotropes of CarbonAllotropes of Carbon

Carbon onlyCarbon only(no other atom) compounds(no other atom) compounds

FUNCTIONAL GROUPSFUNCTIONAL GROUPS1.1. AlkaneAlkane2.2. AlkeneAlkene3.3. AlkyneAlkyne4.4. Alkyl halideAlkyl halide5.5. AromaticAromatic6.6. AlcoholAlcohol7.7. EthersEthers8.8. AldehydeAldehyde9.9. KetoneKetone10.10. Carboxylic AcidCarboxylic Acid11.11. EsterEster12.12. AmineAmine13.13. AmideAmide

Organic chemistry is the study of Organic chemistry is the study of compounds containing carbon.compounds containing carbon. The goal of studying Organic The goal of studying Organic chemistry is the making of chemistry is the making of carbon-carbon bonds, C-X, C-O, C-N,carbon-carbon bonds, C-X, C-O, C-N,and C-S bonds to make new moleculesand C-S bonds to make new molecules

Inorganic molecules like CO, andInorganic molecules like CO, and COCO33

-2-2 are not considered organic are not considered organic

molecules.molecules.

imp

ort

ance

imp

ort

ance

1. Alkanes1. Alkanes

Figure 11.4Figure 11.4

10

NameName # of # of C'sC's Structural FormulaStructural Formula

BP BP (C(C))

MP MP (C(C))

methanemethane 11 CHCH44

-161-161 -183-183

ethaneethane 22 CHCH33CHCH

33-88-88 -172-172

propanepropane 33 CHCH33CHCH

22CHCH33

-45-45 -187-187

butanebutane 44 CHCH33CHCH

22CHCH22CHCH

33-.5-.5 -138-138

pentanepentane 55 CHCH33CHCH

22CHCH22CHCH

22CHCH33

3636 -130-130

hexanehexane 66 CHCH33CHCH

22CHCH22CHCH

22CHCH22CHCH

336969 -95-95

heptaneheptane 77 CHCH33CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH33

9898 -90-90

octaneoctane 88 CHCH33CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH22CHCH

33125125 -57-57

nonanenonane 99 CHCH33CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH33

151151 -54-54

decanedecane 1010 CHCH33CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH22CHCH

22CHCH22CHCH

33

175175 -30-30

AlkanesAlkanes

12

NameName Structural FormulaStructural Formula

methanemethane CC CHCH44

ethaneethane CHCH33CHCH

33

propanepropane CHCH33CHCH

22CHCH33

butanebutane CHCH33CHCH

22CHCH22CHCH

33

pentanepentane CHCH33CHCH

22CHCH22CHCH

22CHCH33

Abbreviated, common method to write organic cmpdsAbbreviated, common method to write organic cmpds

ALKANESALKANES• There are frequently many There are frequently many

hydrocarbons with the same formula. hydrocarbons with the same formula. These are called structural isomers.These are called structural isomers.

CC55HH1212 has three isomers has three isomers

CC1010HH2222 has 75 isomers has 75 isomers

CC2020HH4242 has 366,319 isomers has 366,319 isomers

Isomers of Isomers of Butane-5 Butane-5 Carbon Carbon chainschains

CC66HH1414 has five isomers, has five isomers,

draw them.draw them.

CycloalkanesCycloalkanes

• Cycloalkanes are ring structures and Cycloalkanes are ring structures and have the general formula Chave the general formula CnnHH2n2n. .

• Do not confuse these compounds Do not confuse these compounds with the alkenes which have the with the alkenes which have the same general formula. same general formula.

2. ALKENE AND 3. ALKYNE2. ALKENE AND 3. ALKYNE

• These compounds are referred to as These compounds are referred to as unsaturated. unsaturated.

• Alkenes contain one or more double Alkenes contain one or more double bonds and alkynes contain one or more bonds and alkynes contain one or more triple bonds.triple bonds.

Saturated Hydrocarbon CSaturated Hydrocarbon C1515HH3232

Saturated –vs- UnsaturatedSaturated –vs- Unsaturated

Unsaturated HydrocarbonUnsaturated Hydrocarbon

Contains either double and/or triple bondsContains either double and/or triple bonds

Notice how the chains do not line upNotice how the chains do not line up

2121

Single bonds only FatsSingle bonds only Fats

Double bonds FatsDouble bonds Fats

ALKENESALKENES

ALKYNEALKYNE

Physical properties Physical properties changechange

Isomers have different physical as well asdifferent chemical properties

NomenclatureNomenclature• Organic Functional Groups and NomenclatureOrganic Functional Groups and Nomenclature

• SubstituentsSubstituents - saturated carbon substituents are called - saturated carbon substituents are called alkyl groups and are named based on the naming of the alkyl groups and are named based on the naming of the normal alkanes.normal alkanes.

methy l

e thyl

CH3

CH2CH3 Et

MeC

H

H

H

C

H

H

C H

H

H

NomenclatureNomenclature

HaloalkaneHaloalkane

2727

AlcoholAlcohol

2828

EtherEther

CH3 CH2 O CH2 CH3

2929

AmineAmine

3030

AldehydeAldehyde

CH3 C

O

H

3131

KetoneKetone

3232

Carboxylic acidCarboxylic acid

CH3 C OH

O

3333

EsterEster

CH3 C O

O

CH3

3434

AmideAmide

3535

Draw the followingDraw the following

• ButaneButane

• ButeneButene

• ButyneButyne

• ButanolButanol

• ButanalButanal

• ButanoneButanone

• Dibutyl etherDibutyl ether

• Butanoic acidButanoic acid

• Ethyl butanoateEthyl butanoate

• Butyl amineButyl amine

• Dibutyl amineDibutyl amine

• Tributyl amineTributyl amine

Common Alcohol NamesCommon Alcohol Names

What is the name of this Alcohol?What is the name of this Alcohol?

methylalcohol

Methanol

The main chain is numbered such that The main chain is numbered such that the first substituent encountered along the first substituent encountered along the chain receives the lowest possible the chain receives the lowest possible

number.number.

NOT

C C C C C

CH3

1 2 3 4 5

2-methylpentane

C C C C C

CH3

12345

4-methylpentane

If two or more identical substituents are attached to If two or more identical substituents are attached to the same C-chain , prefixes di-, tri-, tetra-, etc. are the same C-chain , prefixes di-, tri-, tetra-, etc. are

used with numbers to indicate position.used with numbers to indicate position.

C C C C C

CH3

1 2 3 4 5

2,4-dimethylpentane

CH3

C C C C C

CH3

1

2

3 4 5

2,2-dimethylpentane

CH3

4040

Quiz Chapter 4 Section 3

Provide the IUPAC names of the alkanes below.

CH3CH2CHCH2CHCH3

CH3

CH2CH3

(CH3)2CHCH2CH(CH3)2

3,5-dimethylheptane 2,4-dimethylpentane

If two different substituent's are If two different substituent's are attached to the carbon chain, name attached to the carbon chain, name

them in alphabetical order.them in alphabetical order.

Numbering starts closestNumbering starts closestto 1to 1stst functional group functional group

Numbering starts at Numbering starts at the side with thethe side with theheavier functional heavier functional GroupGroup

C C C C C

CH 2CH3

1 2 3 4 5

CH 3

CC

6 7

3-ethyl, 5-methylheptane

PracticePractice

3-ethylhexane3-ethylhexane

C C C C

C

C C

C

C C C C

C

12

34 5

C C

C6

4343–Nomenclature of Branched Alkyl ChainsNomenclature of Branched Alkyl Chains» Two alkyl groups can be derived from Two alkyl groups can be derived from

propanepropane

4444–Nomenclature of Branched Alkyl ChainsNomenclature of Branched Alkyl Chains» Four groups can be derived from the butane Four groups can be derived from the butane

isomersisomers

44

4545

ExamplesExamples

4646

• Classification of Hydrogen AtomsClassification of Hydrogen Atoms

» Hydrogens take their classification from the Hydrogens take their classification from the carbon they are attached tocarbon they are attached to

46

4747

Quiz Chapter 4 Section 3D

Name the alkane below and identify as 1o, 2o and 3o , all groups of equivalent H.

CH3CH2CHCH2CH3CH3

1o

2o3o

1o

3-methylpentane

4848

–Nomenclature of Alkyl HalidesNomenclature of Alkyl Halides» In common nomenclature the simple In common nomenclature the simple

haloalkanes are named as haloalkanes are named as alkyl halidesalkyl halides• Common nomenclature of simple alkyl halides is accepted by IUPAC Common nomenclature of simple alkyl halides is accepted by IUPAC

and still usedand still used

48

PracticePractice

C C C C C

Br

Cl

C C C C C

Br Br

Br

2-bromo-4-chloropentane

2,2,4-tribromopentane

5050– IUPAC Substitutive NomenclatureIUPAC Substitutive Nomenclature

» An IUPAC name may have up to 4 features: locants, An IUPAC name may have up to 4 features: locants, prefixes, parent compound and suffixesprefixes, parent compound and suffixes

» Numbering generally starts from the end of the chain Numbering generally starts from the end of the chain which is closest to the group named in the suffixwhich is closest to the group named in the suffix

– IUPAC Nomenclature of AlcoholsIUPAC Nomenclature of Alcohols» Select the longest chain containing the hydroxyl and Select the longest chain containing the hydroxyl and

change the suffix name of the corresponding parent change the suffix name of the corresponding parent alkane from -ane to -olalkane from -ane to -ol

» Number the parent to give the hydroxyl the lowest Number the parent to give the hydroxyl the lowest possible numberpossible number

» The other substituents take their locations accordinglyThe other substituents take their locations accordingly50

5151Common Names of simple alcohols are still Common Names of simple alcohols are still

often used and are approved by IUPACoften used and are approved by IUPAC

5252

Common Names of Alcohols

Alkyl group names are approved by IUPAC for naming alcohols:"alkyl group + alcohol."

CH3CH2OH CH3CHCH3

OHCH3CCH2OH

CH3

CH3

Ethanol2 propanol orisopropanol

Neopentylol or2,2-Dimethyl-1-propanol

CH3CH2OH CH3CHCH3

OHCH3CCH2OH

CH3

CH3

5353

» Alcohols with two hydroxyls are called diols Alcohols with two hydroxyls are called diols in IUPAC nomenclature and glycols in in IUPAC nomenclature and glycols in common nomenclaturecommon nomenclature

53

5454

Quiz Chapter 4 Section 3F

Name the following compound.

CH3CHClCH2CHOHCH3

4-chloro-2-pentanol

Draw

5555

Nomenclature of Cycloalkanes

Cyclic alkanes are named with the "cyclo" prefix followed by the alkane name indicating the number of carbon atoms in the ring.

CH2

CH2CH2

CH2 CH2

CH2CH2

cyclopropane cyclobutane

5656

• Nomenclature of CycloalkanesNomenclature of Cycloalkanes

–The prefix cyclo- is added to the name of the The prefix cyclo- is added to the name of the alkane with the same number of carbonsalkane with the same number of carbons

• When one substituent is present it is assumed to be at When one substituent is present it is assumed to be at position one and is not numberedposition one and is not numbered

• When two alkyl substituents are present the one with When two alkyl substituents are present the one with alphabetical priority is given position 1alphabetical priority is given position 1

• Numbering continues to give the other substituent the Numbering continues to give the other substituent the lowest numberlowest number

• Hydroxyl has higher priority than alkyl and is given Hydroxyl has higher priority than alkyl and is given position 1position 1

• If a long chain is attached to a ring with fewer carbons, If a long chain is attached to a ring with fewer carbons, the cycloalkane is considered the substituentthe cycloalkane is considered the substituent

5757Substituted Cycloalkanes

When there are two or more substituents, the positions around the ring are numbered beginning with the substituent first in the alphabet.

.The name of a substitutent is added as a prefix to the cycloalkane name. Alkyl group names are used for simple alkyl group substituents

eethylcyclohexan 1,3-dimethylcyclohexane 1-chloro-2-methylcyclopentane

The cycloalkane also can be named as a substituent on a long chain, which is sometimes more convenient.

CH2CH2CH2OH

3-cyclohexyl-1-propanol

3 2 1

CH2CH3 CH3

CH3

Cl

CH3

5858

PracticePractice

methylcyclopentanemethylcyclopentane

1-ethyl-2-methylcyclopentane1-ethyl-2-methylcyclopentane

Structure, Bonding, and IsomerismStructure, Bonding, and Isomerism

• Alkenes have the possibility of cis- trans- Alkenes have the possibility of cis- trans- isomerism since the pi bond does not isomerism since the pi bond does not permit rotation. permit rotation.

• If a molecule has two double bonds If a molecule has two double bonds between carbon atoms, it is called a between carbon atoms, it is called a “diene.”“diene.”

Double and Triple BondsDouble and Triple Bonds

6161

Name the followingName the following

trans-2-butenetrans-2-butene

Double and Triple BondsDouble and Triple Bonds

trans-2-pentenetrans-2-pentene

Double and Triple BondsDouble and Triple Bonds

Draw a Draw a cis, trans-2,4-heptatrienecis, trans-2,4-heptatriene

cis,trans,trans,cis-2,4,6,8-decatetraene

6565

AROMATIC COMPOUNDSAROMATIC COMPOUNDS

BenzeneBenzene

NaphthaleneNaphthalene

6666

AROMATIC COMPOUNDAROMATIC COMPOUND• See your text for physical properties of See your text for physical properties of

these compounds. these compounds.

• Aromatics like benzene have spAromatics like benzene have sp22 hybridization with hybridization with delocalized pi electronsdelocalized pi electrons. . The The delocalized delocalized bonding is the key to bonding is the key to these compounds. these compounds.

• They do not undergo addition reactions They do not undergo addition reactions like alkenes and alkynes, but rather react like alkenes and alkynes, but rather react by way of by way of substitutionsubstitution. .

6767

Substitution reactions with aromatic compounds,Substitution reactions with aromatic compounds, not additionnot addition

CH3 CH3 + Br No Reaction

CH2 CH2 + Br C C

Br

H

Br

H

HH

+ Br

Br

+ HBr

6868

Naming Aromatic CompoundsNaming Aromatic Compounds

anthracenenapthalene

CH3

CH3

o-Xylene

CH3

Toluene

OH

Phenol

6969X

ortho -- o

meta -- m

para -- p

CH3

CH3

o-Xylene

CH3

CH3

m-Xylene

CH3

CH3

p-Xylene

7070

Synthesis: substitution or Synthesis: substitution or elimination elimination

The following are all substitution reaction. Replacing one The following are all substitution reaction. Replacing one atom with another.atom with another.

• Alkyl halides (3)Alkyl halides (3)

• Reaction with aromatic compounds (3)Reaction with aromatic compounds (3)

• Making an alcohol (1)Making an alcohol (1)

• From Alcohols make aldehydes, ketones, and carboxylic From Alcohols make aldehydes, ketones, and carboxylic acids.acids.

The only other type of synthesis is removing an atom, this The only other type of synthesis is removing an atom, this is called elimination. is called elimination.

Preparation of Alkenes Preparation of Alkenes and Alkynesand Alkynes

• Acetylene aka ethyne, from calcium carbide, CaCAcetylene aka ethyne, from calcium carbide, CaC22

• Steam cracking for the formation of ethylene, Steam cracking for the formation of ethylene, ethene, from ethane. ethene, from ethane.

Addition ReactionsAddition Reactions• Symmetrical addition is simple, but asymmetrical Symmetrical addition is simple, but asymmetrical

addition follows Markovnikov's rule: addition follows Markovnikov's rule: the hydrogen the hydrogen adds to the carbon with the most hydrogenadds to the carbon with the most hydrogen..

For alkynes, the addition is always For alkynes, the addition is always twotwo mole to one mole to one mole of alkyne, the product being a substituted mole of alkyne, the product being a substituted alkane. If hydrogen gas is added, the process is alkane. If hydrogen gas is added, the process is called hydrogenation. called hydrogenation.

7272

These reactions may be carried out by adding HX to a solvent such as acetic acid or dichloromethane in the presence of the alkene, or by bubbling gaseous HX into a solution of the alkene.

The reactivity order of HX in these additions is:>HI >HBr HCl

The reactivity of HCl is very low exceptwith highly substituted alkenes.

Hydrogen halides (HCl, HBr, HI) add to alkenes:

+ H-XBA

X = Cl, Br, I

Addition of Hydrogen Halides to Alkenes: Markovnikov's Rule

7373

Regiochemistry of the Addition Reaction

:

Regiochemistry means the specific carbons of the alkene to which the H and X attach. In unsymmetrical alkenes, there are two possible regiochemistries

2-bromopropane

CH3CHCH3

Br

1-bromopropanevery little formed

CH3CH2CH2Br

+ HBr

2-methylpropene 2-bromo-2-methylpropane

Br

1-bromo-2-methyl- propanevery little formed

CH3CHCH2BrCH3

+ HBr

propene

CH2=CHCH3

7474Markovnikov's Rule

Vladimir Markovnikov (University of Kazan) in 1869:

"The hydrogen of the acid attaches to the carbon that already holds the greater number of hydrogens."

This prediction is called "Markovnikov's Rule."

CH2=CH-CH3

H Br Markovnikov addition product

CH2-CH-CH3

H Br

Addition reactions that follow this rule are called Markovnikov Additions.

Markovnikov AdditionMarkovnikov Addition

The hydrogen adds to the carbon with the most hydrogenThe hydrogen adds to the carbon with the most hydrogen

CH3CH2CH2 C CH1 mol HBr

ethanol

ethanol

CH3CH2CH2 C CH

Br Br

CH3CH2CH2 C CH

Br Br

CH3CH2CH2 C CH

Br Br

Br Br

1 mol HBr

ALKENES: AdditionALKENES: Addition

7777Examples of the Halogenation Reaction

1-butene

+ Cl2- 9o C

Chlorination

CH3CH2CH=CH21,2-dichlorobutane

CH3CH2CHClCH2Cl

cyclopentene

+ Br2- 5o C

CCl4/ethanol

Bromination

+

trans-1,2-dibromocyclopentane

(Racemic Form)

Br Br BrBr

ALKENE to ALKANEALKENE to ALKANE

ALKENES: EliminationALKENES: Elimination

Benzene ReactionsBenzene Reactionshalogenationhalogenation

+ Br2

Br

+ HBr

Benzene ReactionsBenzene Reactionsnitrationnitration

+ HNO3 (conc)H2SO4 (conc)

NO2

Benzene ReactionsBenzene Reactionsalkylationalkylation

CH3CH2CH2CH2Cl

CH2CH2CH2CH3

AlCl3

ALCOHOLSALCOHOLS

ALCOHOLSALCOHOLS

Naming AlcoholsNaming Alcohols• The alkane name is modified by dropping the e The alkane name is modified by dropping the e

and addingand adding ol. ol.

• If three OH groups are present, the molecule is If three OH groups are present, the molecule is called a called a triol.triol.

CHCH33CHCH22OH is ethanolOH is ethanol

CHCH33C(OH)C(OH)33 is ethantriol is ethantriol

Primary, secondary, and tertiary alcoholsPrimary, secondary, and tertiary alcohols

C OH

R

H

H

C OH

R

R

H

C OH

R

R

R

primary or 1° secondary or 2° tertiary or 3°

What type of alcohol’s are these?What type of alcohol’s are these?

1°, 2°, 3°?1°, 2°, 3°?1°, 2°, 3°?1°, 2°, 3°?

Metalation of AlcoholsMetalation of AlcoholsSodium metal reacts with an alcohol to produce Sodium metal reacts with an alcohol to produce

hydrogen gas and the sodium alkoxide, refered to hydrogen gas and the sodium alkoxide, refered to as a metalation, since the oxygen is still attached.as a metalation, since the oxygen is still attached.

CH3CH2OH + NaH CH3CH2O-Na+ + H2

OH O-Na+

+ NaOH H2O+

8989

Chemistry of AlcoholsChemistry of Alcohols

1.1. Alcohols can go through substitution, Alcohols can go through substitution, and elimination reactionsand elimination reactions

Which means Alcohols are either Which means Alcohols are either oxidized or reducedoxidized or reduced

Formation of ALCOHOLSFormation of ALCOHOLSaddition reaction to an alkeneaddition reaction to an alkene

H2C CH2 + H2OH3PO4

CH3CH2OH

Could also be called an oxidation reactionCould also be called an oxidation reactionbecause we’re adding oxygen to the carbonbecause we’re adding oxygen to the carbon

SubstitutionSubstitution• An alcohol reacts with HX to produce the An alcohol reacts with HX to produce the

alkylhalidealkylhalide and water, where X is Cl, Br, I and water, where X is Cl, Br, I

• CHCH33CHCH22OH + HCl CHOH + HCl CH33CHCH22Cl + HCl + H22OO

EliminationElimination• In the presence of concentrated sulfuric acid and In the presence of concentrated sulfuric acid and

heat an alcohol will eliminate water and form anheat an alcohol will eliminate water and form an alkene; alkene; the reverse of how alcohols are formed. the reverse of how alcohols are formed.

9292

Suggest a method for makingSuggest a method for making

Starting with 1 butene make 2-bromo butane

Starting with 1 butene make 1-bromo butane

CH CH2CH2CH3

HBr

ethanolCH CH3CH2CH3

Br

Markovnikov

CH CH2CH2CH3 CH2 CH2CH2CH3

H3PO4OH

HBr

ethanolCH2 CH2CH2CH3 OH CH2 CH2CH2CH3 Br

9393

Addition to Ethylene orAddition to Ethylene orElimination by ALCOHOLSElimination by ALCOHOLS

H2C CH2 + H2OH3PO4

CH3CH2OH

H2SO4

Forward is an oxidation, the reverse a reduction.

9494

9595• Oxidation of AlcoholsOxidation of Alcohols

–Oxidation of Primary Alcohols to Oxidation of Primary Alcohols to AldehydesAldehydes

» A primary alcohol can be oxidized to an A primary alcohol can be oxidized to an aldehyde or a carboxylic acidaldehyde or a carboxylic acid

• The oxidation is difficult to stop at the aldehyde stage and usually proceeds The oxidation is difficult to stop at the aldehyde stage and usually proceeds to the carboxylic acidto the carboxylic acid

» A reagent which stops the oxidation at the A reagent which stops the oxidation at the aldehyde stage is pyridinium chlorochromate aldehyde stage is pyridinium chlorochromate (PCC)(PCC)

• PCC is made from chromium trioxide under acidic conditionsPCC is made from chromium trioxide under acidic conditions

• It is used in organic solvents such as methylene chloride (CHIt is used in organic solvents such as methylene chloride (CH22ClCl22))

9696

Alcohols can be oxidized to Alcohols can be oxidized to carboxylic acids or ketonescarboxylic acids or ketones

1. 1. primaryprimary alcohols to aldehydes alcohols to aldehydes withwith mild mild Oxidizing agentsOxidizing agents

CH3CH2 OHC

O

HH3C

PCC

PCC = N+ H CrO3Cl-

Pryidinium chlorochromatePryidinium chlorochromatePryidinium chlorochromatePryidinium chlorochromate

Alcohols can be oxidized directly to Alcohols can be oxidized directly to carboxylic acids or ketonescarboxylic acids or ketones

1. 1. primaryprimary alcohols directly to acids alcohols directly to acids by by STRONGSTRONG oxidizing agentsoxidizing agents

CH3CH2 OHC

O

OHH3C

CrO3, H+

Notice lose of 2H+

Alcohols can be oxidized to Alcohols can be oxidized to carboxylic acids or ketonescarboxylic acids or ketones

2. secondary2. secondary alcohols to alcohols to ketonesketones

CH

OH

C

O

CH3H3CCH3CH3

2-propanol propanone

PCC

Notice lose of 2H+

Tertiary alcoholsTertiary alcohols

No reactionNo reaction

Why?Why?Why?Why?

C

OH

CH3CH3

CH3

PCC, or CrCl3no reaction

CARBONYLCOMPOUNDSCARBONYLCOMPOUNDS The The carbonyl groupcarbonyl group is a carbon atom double is a carbon atom double

bonded to an oxygen atom, and is found in bonded to an oxygen atom, and is found in aldehydes, ketones, carboxylic acids, and esters.aldehydes, ketones, carboxylic acids, and esters.

C

O

102102

NaBHNaBH44 or LiAlH or LiAlH44

103103

CARBONYL COMPOUNDSCARBONYL COMPOUNDS

CARBONYL COMPOUNDSCARBONYL COMPOUNDS• The aldehyde has at least one hydrogen The aldehyde has at least one hydrogen

atom bonded the carbonyl carbon. atom bonded the carbonyl carbon.

• The ketone has two carbon atoms bonded The ketone has two carbon atoms bonded to the carbonyl carbon. to the carbonyl carbon.

• The carboxylic acid has an OH bonded to The carboxylic acid has an OH bonded to the carbonyl carbon. the carbonyl carbon.

• The ester is a combination of an alcohol The ester is a combination of an alcohol and a carboxylic acid. and a carboxylic acid.

• aldehyde, RCOH; ketone, RCORaldehyde, RCOH; ketone, RCOR ''; ;

carboxylic acid, RCOOH; ester, RCOORcarboxylic acid, RCOOH; ester, RCOOR ''..

• Carboxylic acidsCarboxylic acids can be formed by oxidizing can be formed by oxidizing primary alcohols or aldehydes. primary alcohols or aldehydes.

• Reducing aldehydes and acids with NaBHReducing aldehydes and acids with NaBH44 or or LiAlHLiAlH44 produces a produces a primary alcohol.primary alcohol.

• Reduction of aReduction of a ketoneketone produces a secondary produces a secondary alcohol.alcohol.

CARBONYL COMPOUNDSCARBONYL COMPOUNDS

107107

–The Use of Lithium ReagentsThe Use of Lithium Reagents

»Organolithium reagents react Organolithium reagents react similarly to Grignard reagentssimilarly to Grignard reagents

• Organolithium reagents tend to be Organolithium reagents tend to be more reactivemore reactive

108108

The Use of Sodium AlkynidesThe Use of Sodium Alkynides

»Sodium alkynides react with Sodium alkynides react with carbonyl compounds such as carbonyl compounds such as aldehydes and ketones to form aldehydes and ketones to form new carbon-carbon bondsnew carbon-carbon bonds

109109

EstersEsters• Form from carboxylic acids and alcohols when Form from carboxylic acids and alcohols when

heated with sulfuric acid. They are named from heated with sulfuric acid. They are named from the alcohol and the acid with an ate endingthe alcohol and the acid with an ate ending

CH3CH2OH + CH3COOH CH3COOCH2CH3

110110

EstersSynthesis of Esters

Direct Esterification of Carboxylic Acids

Carboxylic acids and alcohols react in the presence of a small amount of strong acid to give esters.

COOH

Benzoic acid

+ CH3OH

Methanol

H+

COOCH3

+ H2O

Methyl benzoate

Esterifications are acid-catalyzed equilibrium reactions. Catalytic amounts of concentrated sulfuric acid or hydrochloric acid are used. Usually a large excess of the alcohol (10- or 15-fold) is used to drive the equilibrium to the product side. Product formation can also be promoted by removing the water as it is formed.

111111

This mechanism for esterification is consistent with the incorporation of the isotopic label:

C6H5COHO=

+ CH3OHH+

C6H5COCH3

O=

+ H2O

A Mechanism for Acid-Catalyzed Hydrolysis of Esters

Since every step is reversible, the reverse of the esterification scheme is the mechanism for the acid-catalyzed hydrolysis of esters.

C6H5COCH3

O=

+ H2OH+

C6H5COHO=

+ CH3OH

The direction of the reaction is controlled by the relative concentrations of water versus alcohol.

112112Transesterification

This is a process whereby the ester of one alcohol may be converted into the ester of a second alcohol by the equilibrium:

RCOR' + R''OHO= H+

RCOR'' + R'OHO=

An example

CH2=CHCOCH3

O=

+ CH3CH2CH2CH2OHH+

Methyl acrylate Butyl alcohol

CH2=CHCOCH2CH2CH2CH3

O=

+ CH3OHMethyl alcohol

The equilibrium is shifted to the product side by using an excess of butyl alcohol and/or distilling out the lower boiling methanol from the reaction mixture.

Butyl acrylate

Alkyl halides RXAlkyl halides RX• React to form alcohols in water using a React to form alcohols in water using a

strong base like NaOH, substitution strong base like NaOH, substitution reaction. reaction.

• In an alcohol solvent, the same reactants In an alcohol solvent, the same reactants form an alkene, elimination reaction.form an alkene, elimination reaction.

CH2 CH2CH2CH3

NaOHBr CH2 CH2CH2CH3 OH

HeatCH2 CH2CH2CH3 OH CH CH2CH2CH3

Ethers R-O-R’Ethers R-O-R’ (Additional material)(Additional material)

• EthersEthers, R-O-R', can be formed from the , R-O-R', can be formed from the reaction of alcohols when heated in the reaction of alcohols when heated in the presence of concentrated sulfuric acid. presence of concentrated sulfuric acid.

• See Lab IVCX 15See Lab IVCX 15

sulfuricCH2 CH2CH2CH3 OH CH2 CH2CH2CH3 O2 CH2 CH3CH2CH2

11.6 FATS AND OILS11.6 FATS AND OILS• Fats and oils are esters of glycerolFats and oils are esters of glycerol

1, 2, 3-propanetriol1, 2, 3-propanetriol

• The R group of the triester is a long chain fatty The R group of the triester is a long chain fatty acid. acid.

BOOM!BOOM!

FATS AND OILSFATS AND OILS

• Some fats are saturated, some Some fats are saturated, some unsaturated, and some are unsaturated, and some are polyunsaturated. polyunsaturated.

• When the triester is hydrolyzed with strong When the triester is hydrolyzed with strong base, the sodium or potassium salt forms base, the sodium or potassium salt forms and is called a soap. and is called a soap.

–The process is also called saponfication. The process is also called saponfication.

Single bonds only FatsSingle bonds only Fats

Double bonds FatsDouble bonds Fats

AMINES AND AMIDESAMINES AND AMIDES

• React as bases and have bad smellsReact as bases and have bad smells

• React with carboxylic acids to form React with carboxylic acids to form amidesamides which are similar which are similar

in structure to esters.in structure to esters.

AMINESAMINES

AMIDESAMIDES

PolymersPolymers

SSUULLFFUURR

11.7 SYNTHETIC POLYMERS11.7 SYNTHETIC POLYMERS• PolymersPolymers are formed from combinations of are formed from combinations of

monomers. monomers.

• They can be classified many ways. They can be classified many ways.

–ThermoplasticsThermoplastics can be heated and can be heated and reformed again and again. reformed again and again.

–ThermosettingThermosetting plastics are heated and plastics are heated and formed, but cannot be heated and formed, but cannot be heated and reformed because of their high degree of reformed because of their high degree of cross-linking. cross-linking.

• Another classification system for polymers is Another classification system for polymers is based on their intended use: based on their intended use:

- plastics - plastics - fibers - fibers

- ElastomersElastomers - coatings - coatings

- adhesives - adhesives

• Polymers can also be classified by the way Polymers can also be classified by the way they form: they form:

–addition polymers addition polymers

–condensation polymerscondensation polymers

11.7 SYNTHETIC POLYMERS11.7 SYNTHETIC POLYMERS

Addition PolymersAddition Polymers• The monomers for these polymers all The monomers for these polymers all

have a double bond. have a double bond.

• If an appropriate initiator is added, If an appropriate initiator is added, these monomers can add to the chain these monomers can add to the chain one at a time by breaking the double one at a time by breaking the double bond. bond.

• This process is called chain growth This process is called chain growth polymerization. polymerization.

• Copolymers are formed from a mixture Copolymers are formed from a mixture of monomers. of monomers.

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Addition: Free RadicalAddition: Free Radical

Polyethylene: AdditionPolyethylene: Addition

PolypropylenePolypropylene

CH2 CH2 CH2 CH2

n

CH CH2 CH CH2

n

CH3 CH3

PolyethylenePolyethylene(a)

Bridging, crosslink

Linear, straight

Branching

TeflonTeflon

What would the following addition polymers look likeWhat would the following addition polymers look like

CF2 CF2 CF2 CF2

n

CH CH2

Cl

for PVC

CH2 CH

OC

O

CH3

methyl methacrylatefor Lucite, Plexiglass

CH CH2

stryenefor styrofoam

PETE (polyethylene terephthalate), HDPE (high-density polyethylene), LDPE (low-density polyethylene), PP (polypropylene), CLPE (cross-linked polyethylene, V (vinyl) or PVC, also RLDPE (resin mix, already recycled. The # is another way of identifying that polymer.

Condensation PolymersCondensation Polymers• These polymers are usually These polymers are usually

copolymers. copolymers.

• One monomer is a dicarboxylic acid One monomer is a dicarboxylic acid and the other monomer is either a and the other monomer is either a dialcohol or a diamine. dialcohol or a diamine.

• These polymers are named as These polymers are named as polyesterspolyesters or or polyamidespolyamides. .

Nylon 66Nylon 66

Polyamide Polyamide ChainsChains

PolymerPolymer

MonomersMonomers

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