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Chapter 12 Organic Compounds with Oxygen and Sulfur

12.1 Alcohols, Thiols, and Ethers

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Alcohols

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

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

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Naming Alcohols

The names of alcohols• in the IUPAC system replace the -e with -ol.• with common names use the name of the alkyl group

followed by alcohol.

Formula IUPAC Common Name

CH4 methane

CH3─OH methanol methyl alcohol

CH3─CH3 ethane

CH3─CH2─OH ethanol ethyl alcohol

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More Names of Alcohols

IUPAC names for longer chains number the chain from the end nearest the -OH group.

CH3─CH2─CH2─OH 1-propanol

OH │CH3─CH─CH2─CH3 2-butanol

CH3 OH │ │CH3─CH─CH2─CH2─CH─CH3 5-methyl-2-hexanol6 5 4 3 2 1

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Some Typical Alcohols

OH |“Rubbing alcohol” CH3—CH—CH3

2-propanol (isopropyl alcohol)

Antifreeze HO—CH2—CH2—OH

1,2-ethanediol (ethylene glycol) OH

| Glycerol HO—CH2—CH—CH2—OH

1,2,3-propanetriol

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Phenols in Medicine

Phenol• is the IUPAC name for benzene with a hydroxyl group.• is used in antiseptics and disinfectants.

Phenol Resorcinol 4-hexylresorcinol

OH

OH

CH2CH2CH2CH2CH2CH3

OH OH

OH

Carbolic Acid

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

OH

OCH3

CH2CH=CH2

eugenol (cloves)

OH

OCH3

CH=CHCH3

isoeugenol (nutmeg)

OH

CH3

C

thymol (thyme)

H

CH3

CH3

OH

OCH3

C

vanillin (vanilla)

H O

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Common Phenols/AlcoholsOH

ortho-phenylphenol (Lysol)

Cl Cl

Cl OH HO Cl

Cl Cl

CH2

3,3',5,5',6,6'-hexachlorodiphenylmethane

(hexachlorophene)

C CC C

CC C

CC C

C C OH

trailmarker for termites

OH

HO

CH2CH2CH2CH2CH2CH3

n-hexylresorcinol (sucrets)

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Common Phenols/Alcohols

C

H

C

C

C OH

C

Csex pheromone for

male Boll Weevil

Cl

OH

Cl

sex attractant for

lonestar tick

C C C C

OH

Caggregating pheromone

for Bark Beetle

C C C

C

C C

OH

C C

C

C

sex pheromone for Bark Beetle

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Common PhenolsOH

OH

(CH2)7 CH CH (CH2)5 CH3

oil of Poison Ivy

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Herbicides produced by Phenols

Cl

Cl

O C COH

O

2,4-dichlorophenoxy acetic acid

(2,4-D)

Cl

Cl

O

Cl

C COH

O

2,4,5-trichlorophenoxy acetic acid

(2,4,5-T)

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Write the structure of each of the following:

A. 3-pentanol

B. ethyl alcohol

C. para-methylphenol

Learning Check

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Solution

Write the structure of each of the following:A. 3-pentanol OH

|CH3—CH2—CH—CH2—CH3

B. ethyl alcohol CH3—CH2—OH

C. para-methylphenol

OH

CH3

Thiols

Thiols• contain sulfur• are similar to alcohols• contain a thiol (-SH) group• often have strong odors• found in cheese, onions, garlic,

and oysters• are used to detect gas leaks

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1818

Thiols are named in the IUPAC

system by adding thiol to the alkane name of the longest carbon chain.

(Methyl Mercaptan)

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Striped Skunk (Mephitis mephitis) Thiols

CH3

C

H

C

CH2SH

H

CH3CHCH2CH2SH

CH3

N CH2SH

E-2-buten-1-thiol 38-44%

3-methyl-1-butanethiol 18-26%

2-quinolinemethanethiol 3-12%

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For pets that have been sprayed, bathe the animal in a mixture of 1 quart of 3% hydrogen peroxide (from drug store), 1/4 cup of baking soda (sodium bicarbonate) and a teaspoon of liquid detergent. After 5 minutes rinse the animal with water. Repeat if necessary. The mixture must be used after mixing and will not work if it is stored for any length of time. DO NOT STORE IN A CLOSED CONTAINER - it releases oxygen gas so it could break the container. This mixture may bleach the pet's hair.

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Why tomato juice is believed to eliminate skunk odor. Bathing an animal in tomato juice seems to work because at high doses of skunk spray the human nose quits smelling the odor (olfactory fatigue). When this happens, the odor of tomato juice can easily be detected. A person suffering olfactory fatigue to skunk spray will swear that the skunk odor is gone and was neutralized by the tomato juice. Another person coming on the scene at this point will readily confirm that the skunk spray has not been neutralized by the tomato juice.

Quickly And Safely Eliminates Odors On PetsThiotrol Spray is specially formulated to neutralize, not mask, offensive skunk odor on pets, people, clothing, carpets, and other contaminated surfaces.DirectionsCompletely saturate affected areas with the high output pump sprayer. Work into fur, clothing, or carpet and allow to dry. Resaturate affected area and let dry. To avoid eyes, apply to face using a saturated cloth. Should any odors remain, locate odor source and reapply. Thiotrol Spray CautionFor topical use only. Avoid contact with eyes. Sold Exclusively Through Veterinarians

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Ethers

An ether• contains an ─O─ between two carbon groups.• has a common name that gives the alkyl names of the attached

groups, followed by ether.

CH3─O─CH3 CH3─CH2─O─CH3

dimethyl ether ethyl methyl ether

Propyl People Ether

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Ethers as Anesthetics

Anesthetics • inhibit pain signals to the brain.• like diethyl ether, CH3─CH2─O─CH2─CH3, were used

for over a century, but caused nausea and were flammable.

• developed by the 1960s were nonflammable.

Ethrane (enflurane) Penthrane

F C O C C Cl

F

F

F

F F

H

Cl C C O C H

H

Cl

F

F H

H

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12.2 Properties of Alcohols and Ethers

Chapter 12 Organic Compounds with Oxygen and Sulfur

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Boiling Points of Alcohols

Alcohols• contain polar OH

groups. • form hydrogen bonds

with other alcohol molecules.

• have higher boiling points than alkanes and ethers of similar mass.

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Boiling Points of Ethers

Ethers• do not have a polar

group.• have an O atom, but

there is no H attached.

• cannot form hydrogen bonds between ether molecules.

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Solubility of Alcohols and Ethers in Water

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

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

C atoms.

Copyright © 2009 by Pearson Education, Inc.

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Comparing Boiling Points and Solubility

Copyright © 2009 by Pearson Education, Inc.

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Chapter 12 Organic Compounds with Oxygen and Sulfur

12.3 Reactions of Alcohols and Thiols

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Combustion of Alcohols

Alcohols undergo combustion with O2 to produce CO2 and H2O.

CH3—CH2—OH + 3O2 2CO2 + 3H2O + Energy

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Alcohols undergo• dehydration when heated with an acid catalyst.• the loss of —H and —OH from adjacent carbon

atoms. H OH

| | H+, heatH—C—C—H H—C=C—H + H2O

| | | | H H H H alcohol alkene

Dehydration of Alcohols

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Oxidation and Reduction

In an oxidation, • there is an increase in the number of C-O bonds.• there is a loss of H.

In a reduction,• there is a decrease in the number of C-O bonds.• there is a gain of H.

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Oxidation and Reduction

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Oxidation of Ethanol in the Body

In the body,• enzymes in the liver oxidize ethanol.• the aldehyde produced impairs coordination.• blood alcohol over 0.4% can be fatal.

Ethyl alcohol Acetaldehyde Acetic acid

CH3CH2OH CH3CH CH3COH

O O

CO2

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

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

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

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

Ethanol, CH3CH2OH

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% Ethanol Product

50% Whiskey, rum, brandy

40% Flavoring extracts

15-25% ListerineTM, ScopeTM

20% Formula 44DTM

12% Wine, DristanTM

10% NyquilTM, CepacolTM

3-9% Beer, LavorisTM

Alcohol Contents in Common Products

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Oxidation of Thiols

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

[O]

CH3─SH + HS─CH3 CH3─S─S─CH3 + H2O

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Chapter 12 Organic Compounds with Oxygen and Sulfur

12.4 Aldehydes and Ketones

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Carbonyl Group in Aldehydes and Ketones

A carbonyl group• in an aldehyde is

attached to at least one H atom.

• in a ketone is attached to two carbon groups.

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Naming Aldehydes

An aldehyde• has an IUPAC name in which the -e in the alkane name is changed

to –al.• has a common name for the first four aldehydes that use the

prefixes: form (1C), acet (2C), propion (3C), and butyr (4C), followed by aldehyde.

Methanal Ethanal Propanal (formaldehyde) (acetaldehyde) (propionaldehyde)

H C H

O

CH3 C H

O

CH3CH2 C H

O

•In a linear expression, the aldehyde group is often written as:

CHO

H3CC

H

O

is equivalent to CH3CHO

•In the linear expression of a ketone, the carbonyl group is written as:

CO

H3CC

CH3

O

is equivalent to CH3COCH3

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Naming Aldehydes

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Aldehydes in Flavorings

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

Benzaldehyde (almonds)

Cinnamaldehyde (cinnamon)

C

O

H

CH CH C

O

H

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Naming Ketones

In naming ketones• in the IUPAC system, the -e in the alkane name is replaced with –

one.• with a common name, the alkyl groups attached to the carbonyl

group are named alphabetically, followed by ketone.

Propanone 2-butanone (dimethyl ketone) (ethyl methyl ketone)

CH3 C CH3

O

CH3 C CH2CH3

O

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Ketones in Common Use

Nail polish remover, solvent

Propanone, dimethylketone, acetone

Butter flavoring(Butanedione)

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Aldehydes & Ketones in Nature

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C CC

C

C C

O

Violet (Irone)

C

OH

salicylaldehyde

(meadowsweet)

OHC

O

O

Piperonal

(Heliotrope)

OH

C

CH3(CH2)4C H

O

(Eucalyptus) CH3(CH2)10C H

O

(Citrus Fruits)

CH3 C C CH3

O O

Raspberries

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C H

O

Benzaldehyde

(Oil of Almonds)

CHO

CH3O

H

O

Vanillin

CH CH C H

O

Oil of Cinnamon

H3CCH3

OCamphor (Mothballs)

CH3

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CH3 CCH3

CHCH2CH2C CH

CH3

C H

O

Citral (Lemon Grass Oil)

C C C C C C C

O

CH3

C C (C)n C

O

n = 4 or 6

Alarm Pheromones in ants

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C C

CH

CH

O

Boll Weevil

Sex Attractant

C

Citral

(Honey Bee Recruiting Pheromone)

H

O

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CC

C

(C)12

C O

Musk Ox Sex Attractant

C

C

(C)n

(C)m

C O

Civet Cat Sex Attractant

m = 4, n = 10

m = 7, n = 7

m = 7, n = 9

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Name the following compounds:

A.

B.

Learning Check

CH3 CH2 CH2 C CH3

O

CH3 C CH2 C H

CH3

CH3

O

2-pentanone; methyl propyl ketone

3,3-dimethylbutanal

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Learning Check Draw the structural formulas for each:

A. 4-methylpentanal

B. 2,3-dichloropropanal

C. 3-methyl-2-butanone

CH3 CH CH2 CH2 C H

CH3 O

Cl CH2 CH C H

Cl O

CH3 CH C CH3

CH3 O

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12.5 Properties of Aldehydes and Ketones

Chapter 12 Organic Compounds with Oxygen and Sulfur

Acetaldehyde Acetone

Hydrogen Bond

Hydrogen Bond

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Boiling Points

Aldehydes and ketones have

• polar carbonyl groups (C=O). + -C=O

• attractions between polar groups. + - + -

C=O C=O• higher boiling points than alkanes and ethers of similar mass.

• lower boiling points than alcohols of similar mass.

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Comparison of Boiling Points

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

Solubility in Water

Acetaldehyde Acetone

Hydrogen Bond

Hydrogen Bond

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Tollens’ Silver Mirror Test

In Tollens’ test,

• Tollens’ reagent,which contains Ag+,

oxidizes aldehydes, but not ketones.

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

Ag+ + e– → Ag(s)

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Benedict’s Test

In Benedict’s test,

• Benedict’s reagent, which contains Cu2+,

reacts with aldehydes that have an adjacent OH group.

• an aldehyde is oxidized to a carboxylic acid, while Cu2+ is reduced to give brick red Cu2O(s).

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Increasing amounts of reducing sugar

green orange red brown