11

AnnouncementsAnnouncements & Agenda& Agenda (03/07/07)(03/07/07)

Exam next Wednesday!Exam next Wednesday! Covers Ch 7, 8, 10-12 (not 12.6, on Exam 3)Covers Ch 7, 8, 10-12 (not 12.6, on Exam 3) Practice Exam Posted!Practice Exam Posted! Come visit Bob!!!Come visit Bob!!!

TodayToday Aromatic Compounds (11.5)Aromatic Compounds (11.5) Polymers (11.4)Polymers (11.4) Properties & Reactions of Alcohols (12.1-12.3)Properties & Reactions of Alcohols (12.1-12.3)

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Last Time: Last Time: Bond Angles in Alkenes & AlkynesBond Angles in Alkenes & Alkynes

According to VSEPR theory: According to VSEPR theory: • the 3 groups bonded to C the 3 groups bonded to C

atoms in a double bond are atoms in a double bond are at 120at 120° ° angles.angles.

• alkenes are flat because thealkenes are flat because the atoms in a double bondatoms in a double bond all all lie in the same plane.lie in the same plane.

• the 2 groups bonded to the 2 groups bonded to each carbon in a triple bond each carbon in a triple bond are at 180° angles.are at 180° angles.

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Last Time: Last Time: CisCis--TransTrans Isomers IsomersIn an alkene, the double bond In an alkene, the double bond • is rigid, i.e. NO ROTATION around the double bond!is rigid, i.e. NO ROTATION around the double bond!• holds attached groups in fixed positions. holds attached groups in fixed positions. • makes cis/trans isomers possible.makes cis/trans isomers possible.• Important in nature – such as in pheromonesImportant in nature – such as in pheromones

CHCH33 CHCH33 CH CH33

CH = CHCH = CH CH = CHCH = CH

ciscis transtrans CHCH33

(similar groups on same side) (similar groups on opp. sides)(similar groups on same side) (similar groups on opp. sides)

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By the way, cyclohexane & other cyclic By the way, cyclohexane & other cyclic compounds are not flat.compounds are not flat.

HOO

H

H

HOH

H

OHH

OH

OH

Example: a monosaccharide

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Geometric Isomerism in cycloalkanes:Geometric Isomerism in cycloalkanes:

H

HH

H

H

HH

HH

Cl

H

H

H

HCl

Cl

H

H

H

HH

Cl

H

Cl

Cyclobutanechlorocyclobutane

1,2-dichlorocyclobutane

Trans = “across”

Cis = same side

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Last Time: Addition ReactionsLast Time: Addition Reactions

• The double/triple The double/triple bond can be broken bond can be broken

• alkenes & alkynes are alkenes & alkynes are very reactive.very reactive.

• In In additionaddition reactions, reactions, reactants are added reactants are added to the carbon atoms in to the carbon atoms in the double or triple the double or triple bond.bond.

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One Last Thing about Hydration…One Last Thing about Hydration…

Hydration is also reversible – the equilibrium amounts of Hydration is also reversible – the equilibrium amounts of alkene compared to alcohol depend on how much water is alkene compared to alcohol depend on how much water is aroundaround..

Lots of water – the reaction tends to use up as much Lots of water – the reaction tends to use up as much water as it can, and most of the alkene forms water as it can, and most of the alkene forms alcohol.alcohol.

If water is removed, water can be pulled off from If water is removed, water can be pulled off from alcohol to form the alkene. (concentrated acid).alcohol to form the alkene. (concentrated acid).

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Conjugated bondsConjugated bonds

If you have alternating double & single bonds, If you have alternating double & single bonds,

• you get “extended, conjugated” pi bonds. you get “extended, conjugated” pi bonds.

• what looks like a single bond in between two double what looks like a single bond in between two double bonds, is actually sort of a double bond itself. bonds, is actually sort of a double bond itself.

• multiple pairs of electrons can spread out all the way multiple pairs of electrons can spread out all the way through the aligned parallel orbitals -> molecules like this!through the aligned parallel orbitals -> molecules like this!

C C

CC

H

H

H

H

H H

CC

CC

H

H

H

H

H

H

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One Important Example: BenzeneOne Important Example: Benzene (Know This One!) (Know This One!)

• a ring of 6 C & 6 H atoms.a ring of 6 C & 6 H atoms.• a flat ring structure drawn with three double bonds. a flat ring structure drawn with three double bonds. • represented by 2 structures because electrons are represented by 2 structures because electrons are

shared among all the C atoms.shared among all the C atoms.

Aromatic Compounds Aromatic Compounds “Special Conjugation”“Special Conjugation”

By the way, aromatics are called as such b/c many of By the way, aromatics are called as such b/c many of them have noticeable odors!them have noticeable odors!

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Benzene and AromaticityBenzene and Aromaticity

Aromatics are compounds that have Aromatics are compounds that have conjugated pi bonds around a ring. Electrons conjugated pi bonds around a ring. Electrons love this, and aromatics are very stable.love this, and aromatics are very stable.

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Occurrences in Nature & HealthOccurrences in Nature & Health

Vanillin Aspirin

Ibuprofen Acetaminophen

COH

O

O

C O CH3

CH

O

OCH3

OH

CH

CH3

COH

O

CH2

CH3

CHH3C

OH

NH

O

C CH3

Aromatics can be bad too Aromatics can be bad too Many are Many are carcinogens! Can interact with DNA.carcinogens! Can interact with DNA.

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Aromatic rings can include N atoms, too. Aromatic rings can include N atoms, too.

They can be 5 or 6 membered rings (and >), fused rings, They can be 5 or 6 membered rings (and >), fused rings, etc.etc.

N N

NNH

H2NHN

HN

O

O

N

H2N CH C

CH2

OH

O

Adenine ThyminePhenylalanine

Pyridine

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By the way, why is blood red?By the way, why is blood red?Highly conjugated pi bonds!Highly conjugated pi bonds!

Fen+N

N N

N

H3C

CH2CH3

CH2

CH3H3C

OHOOHO

It’s the HEME in It’s the HEME in hemoglobin!!!hemoglobin!!!

Note: Highly conjugated molecules are Note: Highly conjugated molecules are typically colored!typically colored!

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11.4 11.4 Polymers of AlkenesPolymers of Alkenes

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Polymers: What are they?Polymers: What are they?

• large, long-chain molecules.large, long-chain molecules.

• found in naturefound in nature• Examples: cellulose in plants, starches in food, Examples: cellulose in plants, starches in food,

proteins, DNA, etc. proteins, DNA, etc.

• also also syntheticsynthetic such as polyethylene and such as polyethylene and polystyrene, Teflon, and nylon.polystyrene, Teflon, and nylon.

• have small repeating units called have small repeating units called monomersmonomers..

• can be made from reaction of small alkenescan be made from reaction of small alkenes

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Common Synthetic PolymersCommon Synthetic Polymers

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Common Synthetic PolymersCommon Synthetic Polymers

Important: Properties of polymers depend on Important: Properties of polymers depend on what monomers they are made from and how what monomers they are made from and how they are put together!they are put together!

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PolymerizationPolymerization

In polymerization, small repeating units In polymerization, small repeating units called called monomersmonomers join to form a long chain join to form a long chain polymer. polymer.

monomer unit repeats

n

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Recycling PlasticsRecycling Plastics

Recycling is simplified by using codes on Recycling is simplified by using codes on plastic items.plastic items.

1 PETE1 PETE Polyethyleneterephtalate Polyethyleneterephtalate

2 HDPE2 HDPE High-density polyethylene High-density polyethylene

3 PV3 PV Polyvinyl chloridePolyvinyl chloride

4 LDPE4 LDPE Low-density polyethyleneLow-density polyethylene

5 PP5 PP Polypropylene Polypropylene

6 PS6 PS Polystyrene Polystyrene

2020

CHAPTER 12!CHAPTER 12!

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28 Good Practice Problems (Ch 12)28 Good Practice Problems (Ch 12)

11 22 33 44 55

12.01, 12.03, 12.07, 12.09, 12.11, 12.01, 12.03, 12.07, 12.09, 12.11, 12.13, 12.15, 12.17, 12.19, 12.23, 12.13, 12.15, 12.17, 12.19, 12.23, 12.25, 12.31, 12.33, 12.35, 12.37, 12.25, 12.31, 12.33, 12.35, 12.37, 12.39, 12.41, 12.43, 12.45, 12.49, 12.39, 12.41, 12.43, 12.45, 12.49, 12.51, 12.53, 12.55, 12.63, 12.65, 12.51, 12.53, 12.55, 12.63, 12.65, 12.67, 12.71, 12.75 12.67, 12.71, 12.75

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An An alcoholalcohol contains a hydroxyl group ( contains a hydroxyl group (—OH) —OH) attached to a carbon chain.attached to a carbon chain.

• occur in many important molecules like sugars and -ol occur in many important molecules like sugars and -ol compounds (cholesterol, menthol, etc.) compounds (cholesterol, menthol, etc.)

A A phenolphenol contains a contains a hydroxyl group ( hydroxyl group (—OH) attached —OH) attached to a benzene ring.to a benzene ring.

water alcoholwater alcohol phenol phenol

AlcoholsAlcohols

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Properties of AlcoholsProperties of Alcohols

• contain polar OH groups. contain polar OH groups. • form hydrogen bonds with form hydrogen bonds with

other alcohol molecules.other alcohol molecules.• Short alcohols (1-4 C Short alcohols (1-4 C

atoms) are soluble in atoms) are soluble in waterwater

• > 4 C atoms less soluble> 4 C atoms less soluble

• have much higher BPs have much higher BPs than alkanes of similar than alkanes of similar mass.mass.

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Some Typical Alcohols (Know These)Some Typical Alcohols (Know These)

OHOH ||““rubbing alcohol”rubbing alcohol” CHCH33——CHCH——CHCH33

2-propanol (2-propanol (isopropyl alcoholisopropyl alcohol))

antifreeze antifreeze HOHO——CHCH22——CHCH22——OHOH

1,2-ethanediol (1,2-ethanediol (ethylene glycolethylene glycol)) OHOH

|| glycerolglycerol HOHO——CHCH22——CHCH——CHCH22——OHOH

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

Could make you sickCould make you sick

Will kill youWill kill you

Part of cooking oilPart of cooking oil

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http://www.annals.org/cgi/content/full/122/6/456http://www.annals.org/cgi/content/full/122/6/456

The Elixir Sulfanilamide disaster of 1937 The Elixir Sulfanilamide disaster of 1937

105 people died 105 people died

1938 Federal Food, Drug and Cosmetic 1938 Federal Food, Drug and Cosmetic Act, which required proof of safety before Act, which required proof of safety before the release of a new drug the release of a new drug

In the 1980s similar incident happened in In the 1980s similar incident happened in Haiti killing dozens of Haitian infantsHaiti killing dozens of Haitian infants

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Properties of PhenolProperties of Phenol

• is soluble in water. is soluble in water.

• has a hydroxyl group that ionizes slightly has a hydroxyl group that ionizes slightly (weak acid). (weak acid).

• is corrosive and irritating to skin.is corrosive and irritating to skin.

OH O-

+ H2O + H3O+

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Derivatives of PhenolDerivatives of PhenolCompounds of phenol are the active ingredients in the Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint.essential oils of cloves, vanilla, nutmeg, and mint.

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Drawing structures revisitedDrawing structures revisited

HC

HC

CH

CH

CH

HC

CH3CH2CH2CHCH3

OH

HC

HC

C

CH

CH

HC

OH

OH

OH

2-pentanol

Benzene

Phenol

Traditional drawing Abbreviated drawing

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Naming AlcoholsNaming Alcohols• IUPAC: Alcohols will be called somethingIUPAC: Alcohols will be called somethingolol• If other functional groups present, the -OH group will sometimes If other functional groups present, the -OH group will sometimes

be named as a “be named as a “hydroxylhydroxyl” group” group

FormulaFormula IUPAC IUPAC Common NameCommon Name

CHCH4 4 methanmethanee

CHCH33─OH ─OH methanmethanolol methyl alcohol methyl alcohol

CHCH33─CH─CH33 ethanethanee

CHCH33─CH─CH22─OH ─OH ethanethanolol ethyl alcohol ethyl alcohol

• Also know common names for propyl alcohol and those mentioned Also know common names for propyl alcohol and those mentioned

earlierearlier

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• determined by the number of alkyl groups attached to determined by the number of alkyl groups attached to the carbon bonded to the hydroxyl.the carbon bonded to the hydroxyl.

• primary (1°), secondary (2°), or tertiary(3).primary (1°), secondary (2°), or tertiary(3).

Primary (1º) Secondary (2º) Tertiary (3ºPrimary (1º) Secondary (2º) Tertiary (3º))1 group 1 group 2 groups 2 groups 3 groups 3 groups HH CHCH33 CHCH33

|| || | |

CHCH33——CC——OH OH CHCH33——CC——OHOH CHCH33——CC——OHOH | | || | | H H H H CHCH33

Classification of AlcoholsClassification of Alcohols

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Reactions of AlcoholsReactions of Alcohols

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Combustion of AlcoholsCombustion of Alcohols

Alcohols undergo Alcohols undergo combustioncombustion with Owith O22 to produce to produce

COCO22 and H and H22O.O.

2CH2CH33OH + 3OOH + 3O22 2CO 2CO22 + 4H + 4H22O + HeatO + Heat

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• Alcohols Alcohols dehydratedehydrate when heated with an acid catalystwhen heated with an acid catalyst• Lose Lose —H and —OH from —H and —OH from adjacentadjacent carbon atoms carbon atoms

HH OHOH| | ||

HH——CC——CC——H H H H++, heat , heat HH——C=CC=C——H + H + HH22OO| | || | | ||

H H H H H H H H

alcoholalcohol alkenealkene

Dehydration of AlcoholsDehydration of Alcohols

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Learning CheckLearning Check

Write the equations for the reaction of 2-Write the equations for the reaction of 2-propanol when it undergoespropanol when it undergoes

1. combustion.1. combustion.

2. dehydration.2. dehydration.

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SolutionSolution

OHOH ││CHCH33─CH─CH─CH─CH3 3

= = 2-propanol 2-propanol = C= C33HH88O O

1. combustion1. combustion

2C2C33HH88O + 9OO + 9O22 6CO6CO22 + 8H + 8H22OO

2. dehydration2. dehydration OHOH │ │ HH++

CHCH33─CH─CH─CH─CH3 3 CHCH33─CH=CH─CH=CH22 + H + H22OO

Major Product: Alkene w/ Major Product: Alkene w/ more alkyl substiuentsmore alkyl substiuents

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When a primary alcohol is oxidized, [O],When a primary alcohol is oxidized, [O],• one H is removed from the –OH. one H is removed from the –OH. • another H is removed from the C bonded to -OH.another H is removed from the C bonded to -OH.• an aldehyde is produced.an aldehyde is produced.

[O][O] PrimaryPrimary alcoholalcohol AldehydeAldehyde

OOHH O O || [O] [O] ||||

CHCH33——CC——HH CH CH33——CC——H + H + HH22OO ||

HH EthanolEthanol Ethanal Ethanal (ethyl alcohol)(ethyl alcohol) (acetaldehyde) (acetaldehyde)

Oxidation of Primary (1Oxidation of Primary (1) ) AlcoholsAlcohols

This is a carbonyl This is a carbonyl group…group…

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Oxidation of Secondary (2Oxidation of Secondary (2) Alcohols) AlcoholsWhen a secondary alcohol is oxidized, [O],When a secondary alcohol is oxidized, [O],• one H is removed from the –OH.one H is removed from the –OH.• another H is removed from the C bonded to -OH.another H is removed from the C bonded to -OH.• a ketone is produced. a ketone is produced.

[O][O] secondary alcoholsecondary alcohol ketoneketone

OOHH O O ││ [O] [O] ║║

CHCH33─C─CH─C─CH33 CH CH33─C─CH─C─CH3 3 + + HH22OO

││ HH

2-propanol (isopropyl alcohol) 2-propanol (dimethyl ketone)2-propanol (isopropyl alcohol) 2-propanol (dimethyl ketone)

ASK ME ABOUT “R”!!!ASK ME ABOUT “R”!!!

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Oxidation of Tertiary ( 3)Oxidation of Tertiary ( 3)AlcoholsAlcohols

Tertiary 3Tertiary 3 alcohols do not readily oxidize. alcohols do not readily oxidize. [O] [O]

Tertiary alcoholTertiary alcohol no reactionno reaction OOHH

││ [O][O]

CHCH33─C─CH─C─CH33 no productno product ││

CHCH3 3 no no HH on the C-OH to oxidize on the C-OH to oxidize

2-methyl-2-propanol2-methyl-2-propanol

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Oxidation of Ethanol in the BodyOxidation of Ethanol in the Body

In the body,In the body,

• enzymes in the liver oxidize ethanol.enzymes in the liver oxidize ethanol.

• aldehyde product impairs coordination.aldehyde product impairs coordination.• blood alcohol over 0.4% can be fatal. blood alcohol over 0.4% can be fatal.

O O O O ║ ║║ ║CHCH33CHCH22OH CHOH CH33CH CHCH CH33COH 2COCOH 2CO22 + H + H22OO

ethanol acetaldehyde ethanol acetaldehyde

acetic acidacetic acid

4040

• acts as a depressant.acts as a depressant.• kills or disables more kills or disables more

people than any other drug.people than any other drug.• is metabolized at a rate of is metabolized at a rate of

12-15 mg/dL per hour by a 12-15 mg/dL per hour by a social drinker.social drinker.

• is metabolized at a rate of is metabolized at a rate of 30 mg/dL per hour by an 30 mg/dL per hour by an alcoholic. alcoholic.

Ethanol CHEthanol CH33CHCH22OHOH

4141

Effect of Alcohol on the BodyEffect of Alcohol on the Body

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% Ethanol% Ethanol ProductProduct

50%50% Whiskey, rum, brandyWhiskey, rum, brandy

40%40% Flavoring extractsFlavoring extracts

15-25%15-25% Listerine, Nyquil, ScopeListerine, Nyquil, Scope

12%12% Wine, Dristan, CepacolWine, Dristan, Cepacol

3-9%3-9% Beer, LavorisBeer, Lavoris

Alcohol Contents in Common ProductsAlcohol Contents in Common Products