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AnnouncementsAnnouncements & Agenda& Agenda (03/12/07)(03/12/07)

Pick Up QuizzesPick Up Quizzes

Exam THIS Wednesday!Exam THIS 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 & Key Posted!Practice Exam & Key Posted! Review TONIGHT @ 6:30p (Room 1019)Review TONIGHT @ 6:30p (Room 1019)

TodayToday Ethers & ThiolsEthers & Thiols Aldehydes & Ketones (12.4-12.5)Aldehydes & Ketones (12.4-12.5)

Note Benedict’s Test, Tollen’s Test, & Iodoform Test Note Benedict’s Test, Tollen’s Test, & Iodoform Test will notwill not be on Wednesday’s Exam! be on Wednesday’s Exam!

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

Last Time: Alcohol ClassificationLast Time: Alcohol Classification

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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

Last Time: Dehydration of AlcoholsLast Time: Dehydration of Alcohols

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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)

Last Time: Oxidation of 1Last Time: Oxidation of 1 AlcoholsAlcohols

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

NOTE: If enough NOTE: If enough oxidant around, oxidant around, will go on to form will go on to form carboxylic acid!carboxylic acid!

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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)

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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

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• 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

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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

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EthersEthers• contains an ─O─ between two carbon groups (R-O-R’).contains an ─O─ between two carbon groups (R-O-R’).• has a common name that gives the alkyl names of the has a common name that gives the alkyl names of the

attached groups followed by attached groups followed by etherether..

CHCH33─O─CH─O─CH33 CHCH33─CH─CH22─O─CH─O─CH33

dimethyl ether ethyl methyl etherdimethyl ether ethyl methyl ether

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Boiling Points of EthersBoiling Points of Ethers

EthersEthers• are only modestly are only modestly

polar.polar.• have an O atom, have an O atom,

but there is no H but there is no H attached. attached.

• cannot form cannot form hydrogen bonds hydrogen bonds between between etherether molecules.molecules.

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Solubility of Alcohols & Ethers in WaterSolubility of Alcohols & Ethers in Water

Alcohols and ethers Alcohols and ethers • are more soluble in water than alkanes because the are more soluble in water than alkanes because the

oxygen atom can hydrogen bond with water. oxygen atom can hydrogen bond with water. • with 1-4 C atoms are soluble, but not with 5 or more with 1-4 C atoms are soluble, but not with 5 or more

C atoms. C atoms.

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Comparing Solubility & Boiling PointsComparing Solubility & Boiling Points

Molar Boiling SolubleMolar Boiling Soluble

Compound Mass Point (°C) in Water?Compound Mass Point (°C) in Water?

AlkaneAlkane CH CH33─CH─CH22─CH─CH3 3 4444 -42-42 No No

EtherEther CH CH33─O─CH─O─CH3 3 4646 -23-23 Yes Yes

AlcoholAlcohol CH CH33─CH─CH22─OH─OH 4646 7878 Yes Yes

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Ethers as AnestheticsEthers as Anesthetics

Anesthetics Anesthetics • inhibit pain signals to the brain.inhibit pain signals to the brain.

• like diethyl ether CHlike diethyl ether CH33──CHCH22──OO──CHCH22──CHCH33 were used were used for over a century, but caused nausea and were for over a century, but caused nausea and were flammable.flammable.

• developed by the 1960’s were nonflammable.developed by the 1960’s were nonflammable.

Cl F F Cl F HCl F F Cl F H

│ │ ││ │ │ │ │ ││ │ │

HH──CC──CC──OO──CC──HH HH──CC──CC──OO──CC──HH

│ │ ││ │ │ │ │ ││ │ │ F F F H F HF F F H F H

Ethane(enflurane)Ethane(enflurane) Penthrane Penthrane

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MTBEMTBE

Methyl Methyl terttert-butyl ether -butyl ether CHCH33

││

CHCH33──OO──CC──CHCH33

││

CHCH33

• is second in production of organic chemicals. is second in production of organic chemicals.

• is an additive used to improve gasoline performance.is an additive used to improve gasoline performance.

• use is questioned since the discovery that MTBE has use is questioned since the discovery that MTBE has contaminated water supplies.contaminated water supplies.

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ThiolsThiols• are carbon are carbon

compounds that compounds that contain a –SH group.contain a –SH group.

• are named in the are named in the IUPAC system by IUPAC system by adding adding thiolthiol to the to the alkane name of the alkane name of the longest carbon chain.longest carbon chain.

• the -SH group may the -SH group may also be called a also be called a ““mercaptomercapto” group” group

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ThiolsThiolsThiols Thiols • often have often have

strong odors.strong odors.

• are used to are used to detect gas detect gas leaks.leaks.

• are found in are found in onions, oysters, onions, oysters, and garlic.and garlic.

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Oxidation of ThiolsOxidation of Thiols

When thiols undergo oxidation,When thiols undergo oxidation,• an H atom is lost from each of two –SH groups.an H atom is lost from each of two –SH groups.• the product is a the product is a disulfidedisulfide..

[O][O]

CHCH33─S─SHH + + HHS─CHS─CH33 CH CH33─S─S─CH─S─S─CH3 3 + + HH22OO

2020

Aldehydes and KetonesAldehydes and Ketones

An An aldehydealdehyde contains a contains a carbonyl groupcarbonyl group (C=O), which (C=O), which is a carbon atom with a is a carbon atom with a double bond to an oxygen double bond to an oxygen atom.atom.

In a In a ketoneketone, , the carbon of the carbon of the the carbonyl groupcarbonyl group is is attached to two other carbon attached to two other carbon atoms.atoms.

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Naming AldehydesNaming Aldehydes

2222

Aldehydes in Flavorings Aldehydes in Flavorings Several naturally occurring aldehydes are Several naturally occurring aldehydes are used as flavorings for foods and fragrances.used as flavorings for foods and fragrances.

H

O

C

H

O

CCH=CH

Benzaldehyde (almonds)Benzaldehyde (almonds)

Cinnamaldehyde (cinnamon)Cinnamaldehyde (cinnamon)

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Naming KetonesNaming Ketones• as IUPAC, the -e in the alkane name is replaced with as IUPAC, the -e in the alkane name is replaced with

––oneone..

• With a common name, the alkyl groups attached to the With a common name, the alkyl groups attached to the carbonyl group are named alphabetically followedcarbonyl group are named alphabetically followed

by by ketone.ketone. OO OO

║ ║ ║ ║

CHCH33 ─C─CH ─C─CH33 CH CH33─C─CH─C─CH22─CH─CH33

propanonepropanone 2-butanone 2-butanone

(dimethyl ketone) (dimethyl ketone) (ethyl methyl ketone) (ethyl methyl ketone)

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Ketones in Common UseKetones in Common Use

Nail polish remover, solvent

Propanone, Dimethylketone, Acetone

Butter flavoring

2525

Properties of Aldehydes & KetonesProperties of Aldehydes & Ketones• The polar carbonyl group provides dipole-dipole The polar carbonyl group provides dipole-dipole

interactions.interactions.

+ + -- + + --

C=O C=OC=O C=O

• Without an H on the oxygen, aldehydes and Without an H on the oxygen, aldehydes and ketones cannot form hydrogen bonds to each ketones cannot form hydrogen bonds to each other. other.

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Boiling PointsBoiling Points

Aldehydes and ketones haveAldehydes and ketones have

• polar carbonyl groups (C=O).polar carbonyl groups (C=O). + + --

C=O C=O • attractions between polar groups.attractions between polar groups. + + -- + + --

C=O C=OC=O C=O• higher bp’s than alkanes and ethers of similar mass. higher bp’s than alkanes and ethers of similar mass.

• lower bp’s than alcohols of similar mass. lower bp’s than alcohols of similar mass.

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Comparison of Boiling PointsComparison of Boiling Points

2828

Solubility in WaterSolubility in Water

The electronegative O atom of the carbonyl The electronegative O atom of the carbonyl group of aldehydes and ketones forms group of aldehydes and ketones forms hydrogen bonds with water. hydrogen bonds with water.

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Tollens’ TestTollens’ Test

• Tollens’ reagent,Tollens’ reagent,which contains which contains AgAg++,, oxidizes oxidizes aldehydes, but aldehydes, but not ketones.not ketones.

• AgAg+ + is reduced to is reduced to metallic Ag, metallic Ag, which appears which appears as a “mirror” in as a “mirror” in the test tube.the test tube.

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Benedict’s TestBenedict’s Test

• Benedict’s reagent, Benedict’s reagent, which contains Cuwhich contains Cu2+2+,,

reacts with aldehydes reacts with aldehydes that have an adjacent that have an adjacent OH group.OH group.

• An aldehyde is oxidized An aldehyde is oxidized to a carboxylic acid, to a carboxylic acid, while Cuwhile Cu2+2+ is reduced to is reduced to give red Cugive red Cu22O(s).O(s).