23.2 alcohols, ethers, and amines > 1 copyright © pearson education, inc., or its affiliates....

23.2 Alcohols, Ethers, and Amines >23.2 Alcohols, Ethers, and Amines >

1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Chapter 23Functional Groups

23.1 Introduction to Functional Groups

23.2 Alcohols, Ethers, and Amines

23.3 Carbonyl Compounds23.4 Polymers



Aftershave lotion contains a certain organic compound that imparts a cooling sensation on the skin.

CHEMISTRY & YOUCHEMISTRY & YOU

How can organic chemistry cool you down?



Alcohols

What is the general formula of an alcohol?

AlcoholsAlcohols



What do mouthwash, perfume, and hairspray have in common?

• They all contain an alcohol of some type.

• An alcohol is an organic compound with an —OH group.

Alcohols Alcohols



Alcohols Alcohols

The general formula of an alcohol is ROH.



• The oxygen atom in the —OH group has two pairs of electrons, which compress the R—O—H bond angle.

• As a result, an alcohol molecule has a bent shape.

Alcohols Alcohols

The —OH functional group in alcohols is called a hydroxy group, sometimes called a hydroxyl group.



Aliphatic alcohols can be classified into structural categories according to the number of carbons attached to the carbon with the hydroxy group.

• If only one carbon (or no carbon) is attached to C—OH, the latter carbon is considered a primary carbon, and the alcohol is a primary alcohol.

Alcohols Alcohols

Only one R group is attached to C—OH of a primary (abbreviated 1°) alcohol.




• If two carbons are attached, the carbon is a secondary carbon, which gives a secondary alcohol.

Alcohols Alcohols

Two R groups are attached to C—OH of a secondary (2°) alcohol.




• If three carbons are attached, the carbon is a tertiary carbon, and a tertiary alcohol.

Alcohols Alcohols

Three R groups are attached to C—OH of a tertiary (3°) alcohol.



Both IUPAC and common names are used for alcohols.

AlcoholsAlcohols

Naming Alcohols



AlcoholsAlcohols

To name aliphatic alcohols using the IUPAC system, drop the -e ending of the parent hydrocarbon name and add the ending -ol.

• The parent hydrocarbon is the longest continuous chain of carbons that includes the carbon attached to the hydroxy group.

Naming Alcohols

Ethanol



AlcoholsAlcohols

To name aliphatic alcohols using the IUPAC system, drop the -e ending of the parent hydrocarbon name and add the ending -ol.

• The parent hydrocarbon is numbered so the position of the hydroxy group is given the lowest possible number.

Naming Alcohols

2-propanol



AlcoholsAlcohols

Some alcohols have more than one hydroxy group.

• To name these alcohols using the IUPAC system, simply add the ending -diol or -triol to the parent hydrocarbon name if the alcohol has two or three hydroxy groups, respectively.

Naming Alcohols

1,2-ethanediol 1,2,3-propanetriol



AlcoholsAlcohols

The common names of aliphatic alcohols are written in the same way as those of halocarbons.

• The alkyl group ethyl, for example, is named and followed by the word alcohol, as in ethyl alcohol.

Naming Alcohols

Ethyl alcohol



AlcoholsAlcohols

The common names of aliphatic alcohols are written in the same way as those of halocarbons.

• The alkyl group ethyl, for example, is named and followed by the word alcohol, as in ethyl alcohol.

• The common name for an alcohol with two hydroxy groups is glycol.

Naming Alcohols

Ethyl alcohol



AlcoholsAlcohols

When the hydroxy group is attached directly to an aromatic ring, the compound is called a phenol.

• To assign the IUPAC name, phenol is used as the parent hydrocarbon.

Naming Alcohols

2-methylphenol



AlcoholsAlcohols

When the hydroxy group is attached directly to an aromatic ring, the compound is called a phenol.

• To assign the IUPAC name, phenol is used as the parent hydrocarbon.

Naming Alcohols

2-methylphenol(o-cresol)

– Cresol is the common name for the o, m, and p constitutional isomers of methylphenol.



Interpret DataInterpret Data



Alcohols are capable of intermolecular hydrogen bonding, which is reflected in their physical properties.

• Alcohols boil at higher temperatures than alkanes and halocarbons containing a comparable number of atoms.

AlcoholsAlcohols

Properties of Alcohols



AlcoholsAlcohols

Because alcohols are derivatives of water, they are somewhat soluble in water.


• Alcohols with up to four carbons are completely soluble in water.

• The solubility of alcohols with more than four carbons in the chain is usually much lower.



AlcoholsAlcohols

Alcohols consist of two parts—the carbon chain and the hydroxy group.


• The carbon chain part is nonpolar and is not attracted to water.

• The hydroxy group is polar and strongly interacts with water through hydrogen bonding.



AlcoholsAlcohols



• For alcohols of up to four carbons, the polarity of the hydroxy group overpowers the nonpolarity of the carbon chain.

– As a result, these alcohols are soluble in water.



AlcoholsAlcohols



• For alcohols of up to four carbons, the polarity of the hydroxy group overpowers the nonpolarity of the carbon chain.

– As a result, these alcohols are soluble in water.

• As the number of carbon atoms increases, the nonpolarity of the carbon chain dominates, and the solubility of the alcohol decreases.



2-propanol, which is more familiarly known as rubbing alcohol, is often used as an antiseptic.

AlcoholsAlcohols

Uses of Alcohols



1,2,3-propanetriol is highly soluble in water because it has three hydroxy groups.

AlcoholsAlcohols

Uses of Alcohols

• It has a tendency to absorb water from its surroundings.

• This quality makes it a valuable moistening agent in cosmetics, foods, and pharmaceuticals.



Some antifreezes use 1,2-ethanediol as the main ingredient.

• This alcohol has a high boiling point, 197°C, which helps prevent vehicle engines from overheating.

• Its advantages over liquids with high boiling points are its solubility in water and its low freezing point, –17.4°C.

AlcoholsAlcohols

Uses of Alcohols



• Fermentation is the production of ethanol from sugars by the action of yeasts or bacteria.

– The enzymes of the yeasts or bacteria serve as catalysts for the transformation.

AlcoholsAlcohols

Uses of Alcohols

Most ethanol is produced by yeast fermentation of sugar.



Bread rises because of fermentation.

• Glucose molecules in the dough are broken down by the following fermentation reaction.

C6H12O6(aq) → 2CH3CH2OH(aq) + 2CO2(g) Glucose Ethanol Carbon dioxide

AlcoholsAlcohols

Uses of Alcohols



What functional group do all alcohols contain?



What functional group do all alcohols contain?

All alcohols contain an —OH functional group.



Addition Reactions

How are addition reactions used in organic chemistry?

Addition ReactionsAddition Reactions



The carbon-carbon single bonds in alkanes are not easy to break. In an alkene, however, one of the bonds in the double bond is somewhat weaker.

• This bond is easier to break than a carbon-carbon single bond.

• So, it is sometimes possible for a compound of general structure X—Y to add to a double bond.




The carbon-carbon single bonds in alkanes are not easy to break. In an alkene, however, one of the bonds in the double bond is somewhat weaker.

• In an addition reaction, a substance is added at the double or triple bond of an alkene or alkyne.





Addition reactions are an important method of introducing new functional groups to organic molecules. They are also used to convert alkenes to alkanes.



In the general addition reaction shown below, X and Y represent the two parts of the compound that are added to the alkene.




The addition of water to an alkene is a hydration reaction.


Hydration Reactions

• A hydration reaction results in the formation of an alcohol.

• The addition of water to ethane to form ethanol is a typical hydration reaction.



When the reagent X—Y is a halogen molecule, the product of the reaction is a disubstituted halocarbon.

• The addition of bromine to ethene to form the disubstituted halocarbon 1,2-dibromoethane is an example.


Halogenation Reactions



The addition of bromine to carbon-carbon multiple bonds is often used as a chemical test for unsaturation in an organic molecule.

• Bromine has an orange color, but most bromine-substituted organic compounds are colorless.



After mixing, if the solution remains colorless, the compound is positive for unsaturation.

If the solution remains orange, the compound is negative for unsaturation.



Hydrogen halides, such as HBr or HCl, can also add to a double bond.

• Because the product contains only one substituent, it is called a monosubstituted halocarbon.





The addition of hydrogen to a carbon-carbon double bond to produce an alkane is called a hydrogenation reaction.


Hydrogenation Reactions

• The manufacture of margarine or spreads from various oils is a common application of hydrogenation.

– Saturated fats have higher melting points than unsaturated fats. This is why margarine remains solid at room temperature.



• Ethene is reduced to ethane.

• Cyclohexene is reduced to cyclohexane.


Hydrogenation Reactions

The hydrogenation of a double bond is a reduction reaction.



How are hydration and hydrogenation reactions similar? How are they different?



How are hydration and hydrogenation reactions similar? How are they different?

Both hydration and hydrogenation reactions are addition reactions. Hydration is the addition of water to an alkene, and results in the formation of an alcohol. Hydrogenation is the addition of hydrogen, and results in the formation of an alkane.



Ethers

What is the general formula of an ether?

EthersEthers



Ethers

What is the general formula of an ether?

EthersEthers

• An ether is an organic compound in which oxygen is bonded to two carbon groups.



The general formula of an ether is ROR.

• Like an alcohol, an ether molecule is bent because of the unshared pairs of electrons on the oxygen atom.

EthersEthers



To name an ether using the IUPAC system, first you need to identify the two R groups.

• The smaller R group is treated as part of the substituent, and the -ane and -ene endings are replaced with -oxy.

• The larger R group is the parent hydrocarbon.

EthersEthers



In the common names of ethers, both R groups are treated as substituents.

• The -ane or -ene endings are replaced with -yl for both R groups.

• List the names of the two R groups in alphabetical order and follow with the word ether.

EthersEthers



Menthol is the common name of the organic compound responsible for the cooling sensation in many consumer products. Menthol is a cyclohexanol with two alkyl substituents. Is menthol an alcohol or an ether? How can you tell?




Menthol is the common name of the organic compound responsible for the cooling sensation in many consumer products. Menthol is a cyclohexanol with two alkyl substituents. Is menthol an alcohol or an ether? How can you tell?


Menthol is an alcohol. The ending -ol always indicates an alcohol. An ether is indicated by the ending -oxy or by the word “ether.”



When both R groups are the same, the ether is symmetric.

• The common names of symmetric ethers use the prefix di-.

EthersEthers



Diethyl ether was the first reliable general anesthetic.

EthersEthers

• However, because diethyl ether is highly flammable and often causes nausea, it was eventually replaced by other anesthetics.



• Ethers usually have lower boiling points than alcohols of comparable molar mass, but higher boiling points than comparable hydrocarbons and halocarbons.

• Unlike alcohols, ethers are not capable of forming hydrogen bonds with other ether molecules.

• Ethers can form hydrogen bonds with water.

EthersEthers

– Ethers are more soluble in water than hydrocarbons and halocarbons, but less soluble than alcohols because they form fewer hydrogen bonds.



What is the key difference between a symmetric ether and an asymmetric ether?



What is the key difference between a symmetric ether and an asymmetric ether?

A symmetric ether has two of the same R groups attached to the oxygen atom; an asymmetric ether has two different R groups.



Amines

What is the general formula of an amine?

AminesAmines



Amines

What is the general formula of an amine?

AminesAmines

• An amine is an organic compound in which nitrogen is bonded to a carbon group.

– Amines are similar to ammonia (NH3).



The general formula of an amine is RNH2, R2NH, or R3N.

AminesAmines



Amines can be classified according to the number of R groups attached to the nitrogen atom.

• An amine with the general formula RNH2 is a primary amine because one R group is attached to the nitrogen atom.

• Amines with two or three R groups attached to the nitrogen atom are secondary or tertiary amines, respectively.

AmineAmine



The IUPAC system for naming primary amines is similar to that of alcohols.

• The -e ending of the parent hydrocarbon is changed to -amine.

– Ethanamine is used to make plastics, pharmaceuticals, and pesticides.

– Benzenamine is used to make furniture foam and some of the dyes that give clothes their colors.

AminesAmines

Ethanamine Benzenamine



The common names of primary amines are similar to the IUPAC names.

• The alkyl or aryl group is named and followed by -amine.

AminesAmines



• Because nitrogen is less electronegative than oxygen, the hydrogen bonds in amines are not as strong as those in alcohols.

– As a result, primary amines have lower boiling points than alcohols with a comparable number of carbons.

• Amines can also hydrogen bond with water.

– Smaller amines are soluble in water, but as the number of carbons increase, the solubility in water decreases.

AminesAmines

Like alcohols, primary amines form intermolecular hydrogen bonds.



What functional group is characteristic of primary amines?



What functional group is characteristic of primary amines?

Primary amines are characterized by having an —NH2 group.



The general formula of an alcohol is ROH.

Addition reactions are an important method of introducing new functional groups to organic molecules. They are also used to convert alkenes to alkanes.

The general formula of an ether is ROR.

The general formula of an amine is RNH2, R2NH, or R3N.

Key ConceptsKey Concepts



• alcohol: an organic compound having an —OH (hydroxy) group; the general structure is R—OH

• hydroxy group: the —OH functional group in alcohols

• fermentation: the production of ethanol from sugars by the action of yeast or bacteria

• addition reaction: a reaction in which a substance is added at the double bond of an alkene or at the triple bond of an alkyne

Glossary TermsGlossary Terms



• hydration reaction: a reaction in which water is added to an alkene

• hydrogenation reaction: a reaction in which hydrogen is added to a carbon-carbon double bond to produce an alkane

• ether: an organic compound in which oxygen is bonded to two carbon groups; the general formula is R—O—R

• amine: an organic compound in which nitrogen is bonded to a carbon group

Glossary TermsGlossary Terms



• Chemical reactions can be used to change the structure of organic molecules, often by introducing a new functional group.

• Addition reactions are commonly used in organic chemistry.

BIG IDEABIG IDEA

Carbon Chemistry and Reactions



END OF 23.2END OF 23.2

23.2 alcohols, ethers, and amines > 1 copyright © pearson education, inc., or its affiliates....

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