Single-Bonded Functional Groups

1.3

When you cut yourself, it is often a good idea to swab the cut with rubbing alcohol to disinfect it. Most rubbing alcohols that are sold in drugstores are based on 2-propanol (common name: isopropanol), C3H8O . You can also swab a cut with a rubbing alcohol based on ethanol, C2H6O . Often it is hard to tell the difference between these two compounds. Both have a sharp smell, and both evaporate quickly. Both are effective at killing bacteria and disinfecting wounds. What is the connection between these compounds? Why is their behaviour so similar?

Section Preview/ Specific Expectations

In this section, you will ■

distinguish among the following classes of organic compounds: alkyl halides, alcohols, ethers, and amines

■

describe the effects of intermolecular forces on the physical properties of alcohols, ethers, and amines

■

draw and name alkyl halides, alcohols, ethers, and amines using the IUPAC system

■

identify the common names of some organic compounds

■

communicate your understanding of the following terms: OH (hydroxyl) group, general formula, intermolecular forces hydrogen bonding, dipole-dipole interactions, dispersion forces, alcohol, parent alkane, alkyl halide (haloalkane), ether, alkoxy group, amine

Functional Groups Both 2-propanol and ethanol contain the same functional group, an OH (hydroxyl) group, as shown in Figure 1.12. Because ethanol and 2-propanol have the same OH functional group, their behaviour is similar. CH3

CH

CH3

CH3

CH2

OH

OH 2-propanol Figure 1.12

ethanol

Ethanol and 2-propanol both belong to the alcohol family.

The general formula for a family of simple organic compounds is R + functional group . The letter R stands for any alkyl group. (If more than one alkyl group is present, R ′ and R ′′ are also used.) For example, the general formula ROH refers to any of the following compounds: CH3OH, CH3CH2OH, CH3CH2CH2OH, CH3CH2CH2CH2OH, etc. Organic compounds are named according to their functional group. Generally, the suffix of a compound’s name indicates the most important functional group in the molecule. For example, the suffix -ene indicates the presence of a double bond, and the suffix -ol indicates the presence of a hydroxyl group. Functional groups are a useful way to classify organic compounds, for two reasons: 1. Compounds with the same functional group often have similar

physical properties. In the next two sections, you will learn to recognize various functional groups. You will use functional groups to help you predict the physical properties of compounds. 2. Compounds with the same functional group react chemically in very

Each organic family follows a set pattern. You have just seen that you can represent the hydrocarbon part of a functional family by the letter R. All the structures below belong to the primary amine family. What is the functional group for this family? Write the general formula for an amine.

CH3

similar ways. In Chapter 2, you will learn how compounds with each functional group react. Table 1.4, on the next page, lists some of the most common functional groups.

CH3 CH3

NH2

CH2

CH2

NH2

CH2

NH2

Chapter 1 Classifying Organic Compounds • MHR

21

Table 1.4 Common Functional Groups Type of compound

Suffix

Example

Functional group

alkane

-ane

none

alkene

-ene

C

C

propene

alkyne

-yne

C

C

propyne

alcohol

-ol

C

OH

propanol

amine

-amine

C

N

propanamine

aldehyde

-al

propane

O propanal

C

H

O ketone

propanone

-one

C O carboxylic acid

propanoic acid

-oic acid

C

OH

O ester

methyl propanoate

-oate

C

O

O amide

-amide

C

N

propanamide

Physical Properties and Forces Between Molecules Organic compounds that have the same functional group often have similar physical properties, such as boiling points, melting points, and solubilities. Physical properties are largely determined by intermolecular forces, the forces of attraction and repulsion between particles. Three types of intermolecular forces are introduced below. You will examine these forces further in Chapter 4. • Hydrogen bonding is a strong intermolecular attraction between the hydrogen atom from an NH, OH, or FH group on one molecule, and a nitrogen, oxygen, or fluorine atom on another molecule. • The attractive forces between polar molecules are called dipole-dipole interactions. These forces cause polar molecules to cling to each other. • Dispersion forces are attractive forces that occur between all covalent molecules. These forces are usually very weak for small molecules, but they strengthen as the size of the molecule increases. The process that is outlined on the next page will help you to predict the physical properties of organic compounds by examining the intermolecular forces between molecules. As you progress through the chapter, referring back to this process will enable you to understand the reasons behind trends in physical properties.

22

MHR • Unit 1 Organic Chemistry

Intermolecular Forces and Physical Properties

Draw two or three molecules of the same organic compound close together on a page. If you are considering the solubility of one compound in another, sketch the two different molecules close together. Ask the following questions about the intermolecular interactions between the molecules of each compound: 1. Can the molecules form hydrogen bonds?

If the molecules have OH, NH, or HF bonds, they can form hydrogen O O bonds with themselves and with water. H H H H The diagram to the right illustrates O hydrogen bonding between water H H molecules. If the molecules contain O, N, or F atoms that are not bonded to hydrogen atoms, they may accept hydrogen bonds from water, even though they cannot form hydrogen bonds with themselves. Molecules that can form hydrogen bonds with themselves have a higher boiling point than similar molecules that cannot form hydrogen bonds with themselves. For example, alcohols can form hydrogen bonds, but alkanes cannot. Therefore, alcohols have higher boiling points than alkanes. Molecules that can form hydrogen bonds with water, or can accept hydrogen bonds from water, are usually soluble in water. For example, many alcohols are soluble in water because they can form hydrogen bonds with water. 2. Are the molecules polar ?

The molecules are polar if they have polar bonds, and if these bonds do not act in opposite directions and counteract each other. Polar molecules are attracted to each other by dipole-dipole forces. Polar molecules usually have a higher boiling point than similar non-polar molecules. Also, polar molecules that can form hydrogen bonds have an even higher boiling point than polar molecules that cannot form hydrogen bonds. For example, ethanol, CH3CH2OH, is polar. Its molecules can form hydrogen bonds. Methoxymethane, CH3OCH3 , is an isomer of ethanol. It is also polar, but its molecules cannot form hydrogen bonds. Thus, ethanol has a higher boiling point than methoxymethane. Both of these compounds have a higher boiling point than the non-polar molecule ethane, CH3CH3 . Polar molecules with a large non-polar hydrocarbon part are less polar than polar molecules with a smaller non-polar hydrocarbon part. For example, octanol, CH3CH2CH2CH2CH2CH2CH2CH2OH , is less polar than ethanol, CH3CH2OH. Polar molecules with a large hydrocarbon part are less soluble in water than polar molecules with a smaller hydrocarbon part. For example, octanol, CH3CH2CH2CH2CH2CH2CH2CH2OH , is less soluble in water than ethanol, CH3CH2OH. continued on the next page

Chapter 1 Classifying Organic Compounds • MHR

23

3. How strong are the dispersion forces ?

Dispersion forces are weak intermolecular forces. They are stronger, however, when the hydrocarbon part of a molecule is very large. Thus, a large molecule has stronger dispersion interactions than a smaller molecule. A molecule with a greater number of carbon atoms usually has a higher boiling point than the same type of molecule with fewer carbon atoms. For example, hexane, CH3CH2CH2CH2CH2CH3 has a higher boiling point than ethane, CH3CH3 . The melting points of organic compounds follow approximately the same trend as their boiling points. There are some anomalies, however, due to more complex forces of bonding in solids. In the following ThoughtLab you will use the process in the box above to predict and compare the physical properties of some organic compounds.

ThoughtLab

Comparing Intermolecular Forces

Intermolecular forces affect the physical properties of compounds. In this ThoughtLab, you will compare the intermolecular forces of different organic compounds.

Procedure 1. Draw three molecules of each compound below. (a) propane, CH3CH2CH3 (b) heptane, CH3CH2CH2CH2CH2CH2CH3 (c) 1-propanol, CH3CH2CH2OH (d) 1-heptanol, CH3CH2CH2CH2CH2CH2CH2OH 2. For each compound, consider whether or not hydrogen bonding can occur between its molecules. Use a dashed line to show any hydrogen bonding. 3. For each compound, consider whether or not any polar bonds are present. (a) Use a different-coloured pen to identify any polar bonds. (b) Which compounds are polar? Which compounds are non-polar? Explain your reasoning. 4. Compare your drawings of propane and heptane. (a) Which compound has stronger dispersion forces? Explain your answer. (b) Which compound has a higher boiling point? Explain your answer. 5. Compare your drawings of 1-propanol and 1-heptanol.

24

MHR • Unit 1 Organic Chemistry

(a) Which compound is more polar? Explain your answer. (b) Which compound is more soluble in water? Explain your answer.

Analysis 1. Which compound has a higher solubility in water? (a) a polar compound or a non-polar compound (b) a compound that forms hydrogen bonds with water, or a compound that does not form hydrogen bonds with water (c) CH3CH2CH2OH or CH3CH2CH2CH2CH2OH 2. Which compound has stronger attractions between molecules? (a) a polar compound or a non-polar compound (b) a compound without OH or NH bonds, or a compound with OH or NH bonds 3. Which compound is likely to have a higher boiling point? (a) a polar compound without OH or NH bonds, or a polar compound with OH or NH bonds (b) CH3CH2CH2OH or CH3CH2CH2CH2CH2OH 4. Compare boiling points and solubilities in water for each pair of compounds. Explain your reasoning. (a) ammonia, NH3, and methane, CH4 (b) pentanol, C5H11OH, and pentane, C5H12

Compounds With Single-Bonded Functional Groups Alcohols, alkyl halides, ethers, and amines all have functional groups with single bonds. These compounds have many interesting uses in daily life. As you learn how to identify and name these compounds, think about how the intermolecular forces between their molecules affect their properties and uses.

Alcohols An alcohol is an organic compound that contains the OH functional group. Depending on the position of the hydroxyl group, an alcohol can be primary, secondary, or tertiary. Figure 1.13 gives some examples of alcohols. primary alcohol

secondary alcohol

tertiary alcohol

OH CH2

HO

CH2

CH2

CH3

The hydroxyl group is bonded to a carbon that is bonded to only one other carbon atom.

CH

CH3

CH3 CH2

CH3

CH3

CH3

C OH

The hydroxyl group is bonded to a carbon that is bonded to two other carbon atoms.

The hydroxyl group is bonded to a carbon that is bonded to three other carbon atoms.

Figure 1.13

Table 1.5 lists some common alcohols and their uses. Alcohols are very widely used, and can be found in drug stores, hardware stores, liquor stores, and as a component in many manufactured products.

Table 1.5 Common Alcohols and Their Uses Name methanol

ethanol

2-propanol

Common name(s)

Structure

wood alcohol, methyl alcohol

CH3

grain alcohol, ethyl alcohol

CH3

isopropanol, isopropyl alcohol, rubbing alcohol

OH

CH2

OH

Boiling point

Use(s)

64.6˚C

• solvent in many chemical processes • component of automobile antifreeze

78.2˚C

• solvent in many chemical processes • component of alcoholic beverages • antiseptic liquid • antiseptic liquid

CH3 CH

82.4˚C

OH

CH3 1,2-ethanediol

ethylene glycol

HO

CH2

CH2

OH

197.6˚C

• main component of automobile antifreeze

Alcohols are named from the parent alkane: the alkane with the same basic carbon structure. Follow the steps on the next page to name an alcohol. The Sample Problem that follows gives an example.

Chapter 1 Classifying Organic Compounds • MHR

25

Web

LINK

www.mcgrawhill.ca/links/ chemistry12 Methanol and ethanol are produced industrially from natural, renewable resources. Go to the web site above, and click on Web Links to find out where to go next. Research the processes that produce these important chemicals. From where do they obtain their raw materials?

How to Name an Alcohol Step 1 Locate the longest chain that contains an OH group attached to

one of the carbon atoms. Name the parent alkane. Step 2 Replace the -e at the end of the name of the parent alkane with -ol. Step 3 Add a position number before the root of the name to indicate the

location of the OH group. (Remember to number the main chain of the hydrocarbon so that the hydroxyl group has the lowest possible position number.) If there is more than one OH group, leave the -e in the name of the parent alkane, and put the appropriate prefix (di-, tri-, or tetra-) before the suffix -ol. Step 4 Name and number any other branches on the main chain. Add the

name of these branches to the prefix. Step 5 Put the name together: prefix + root + suffix.

Sample Problem Naming an Alcohol Problem Name the following alcohol. Identify it as primary, secondary, or tertiary.

PROBLEM TIP If an organic compound is complex, with many side branches, the main chain may not be obvious. Sketch the compound in your notebook or on scrap paper. Circle or highlight the main chain.

CH2 HO

CH2

CH2

CH

CH2

CH3

CH3

Solution Step 1 The main chain has six carbon atoms. The name of the parent

alkane is hexane. Step 2 Replacing -e with -ol gives hexanol. Step 3 Add a position number for the OH group, to obtain 1-hexanol. Step 4 A methyl group is present at the third carbon. The prefix

is 3-methyl. Step 5 The full name is 3-methyl-1-hexanol. This is a primary alcohol.

Practice Problems 14. Name each alcohol. Identify it as primary, secondary, or tertiary.

OH (a) CH3

CH2

CH2

OH

(d) CH3

(b)

(e)

OH

26

MHR • Unit 1 Organic Chemistry

CH

CH2

OH

OH

(c)

CH

OH

CH3

15. Draw each alcohol. (a) methanol

(d) 3-ethyl-4-methyl-1-octanol

(b) 2-propanol

(e) 2,4-dimethyl-1-cyclopentanol

(c) 2,2-butanediol 16. Identify any errors in each name. Give the correct name for

the alcohol. (a) 1,3-heptanol

OH HO

CH2

CH2

CH

CH2

CH3

(b) 3-ethyl-4-ethyl-1-decanol

OH (c) 1,2-dimethyl-3-butanol

CH3 CH2

CH

CH3

CH

CH3

OH

17. Sketch a three-dimensional diagram of methanol. Hint: Recall that

the shape around an oxygen atom is bent.

Table 1.6 lists some common physical properties of alcohols. As you learned earlier in this chapter, alcohols are polar molecules that experience hydrogen bonding. The physical properties of alcohols depend on these characteristics.

Table 1.6 Physical Properties of Alcohols Polarity of functional group The OH bond is very polar. As the number of carbon

atoms in an alcohol becomes larger, the alkyl group’s non-polar nature becomes more important than the polar OH bond. Therefore small alcohols are more polar than alcohols with large hydrocarbon portions. Hydrogen bonding

Alcohols experience hydrogen bonding with other alcohol molecules and with water.

Solubility in water

The capacity of alcohols for hydrogen bonding makes them extremely soluble in water. Methanol and ethanol are miscible (infinitely soluble) with water. The solubility of an alcohol decreases as the number of carbon atoms increases.

Melting and boiling points

Due to the strength of the hydrogen bonding, most alcohols have higher melting and boiling points than alkanes with the same number of carbon atoms. Most alcohols are liquids at room temperature.

Additional Characteristics of Alcohols • Alcohols are extremely flammable, and should be treated with caution. • Most alcohols are poisonous. Methanol can cause blindness or death when consumed. Ethanol is consumed widely in moderate quantities, but it causes impairment and/or death when consumed in excess. Chapter 1 Classifying Organic Compounds • MHR

27

Alkyl Halides An alkyl halide (also known as a haloalkane) is an alkane in which one or more hydrogen atoms have been replaced with halogen atoms, such as F, Cl, Br, or I. The functional group of alkyl halides is RX, where X represents a halogen atom. Alkyl halides are similar in structure, polarity, and reactivity to alcohols. To name an alkyl halide, first name the parent hydrocarbon. Then use the prefix fluoro-, chloro-, bromo-, or iodo-, with a position number, to indicate the presence of a fluorine atom, chlorine atom, bromine atom, or iodine atom. The following Sample Problem shows how to name an alkyl halide.

Sample Problem Naming an Alkyl Halide Problem Name the following compound. Br 1 6

2

5 4

3

Br

CH3

Solution The parent hydrocarbon of this compound is cyclohexane. There are two bromine atoms attached at position numbers 1 and 3. Therefore, part of the prefix is 1,3-dibromo-. There is also a methyl group at position number 4. Because the groups are put in alphabetical order, the full prefix is 1,3-dibromo-4-methyl-. (The ring is numbered so that the two bromine atoms have the lowest possible position numbers. See the Problem Tip on page 18.) The full name of the compound is 1,3-dibromo-4-methylcyclohexane.

Practice Problems 18. Draw a condensed structural diagram for each alkyl halide. (a) bromoethane (b) 2,3,4-triiodo-3-methylheptane 19. Name the alkyl halide at the right.

Then draw a condensed structural diagram to represent it.

F F

20. Draw and name an alkyl halide that has three carbon atoms and one

iodine atom. 21. Draw and name a second, different alkyl halide that matches the

description in the previous question.

28

MHR • Unit 1 Organic Chemistry

Ethers Suppose that you removed the H atom from the OH group of an alcohol. This would leave space for another alkyl group to attach to the oxygen atom. CH3CH2OH → CH3CH2O → CH3CH2 OCH3 The compound you have just made is called an ether. An ether is an organic compound that has two alkyl groups joined by an oxygen atom. The general formula of an ether is ROR. You can think of alcohols and ethers as derivatives of the water molecule, as shown in Figure 1.14. Figure 1.15 gives two examples of ethers.

→

O H

H water

→

O R

H

O R

alcohol

R′ ether

Figure 1.14 An alcohol is equivalent to a water molecule with one hydrogen atom replaced by an alkyl group. Similarly, an ether is equivalent to a water molecule with both hydrogen atoms replaced by alkyl groups.

O CH3CH2

O CH2CH3

ethoxyethane (common name: diethyl ether)

CH3

CH2CH2CH3

1-methoxypropane (common name: methyl propyl ether)

Figure 1.15 Until fairly recently, ethoxyethane was widely used as an anaesthetic. It had side effects, such as nausea, however. Compounds such as 1-methoxypropane are now used instead.

To name an ether, follow the steps below. The Sample Problem then shows how to use these steps to give an ether its IUPAC name and its common name. How to Name an Ether IUPAC Name Step 1 Choose the longest alkyl group as the parent alkane. Give it an

alkane name. Step 2 Treat the second alkyl group, along with the oxygen atom, as an

alkoxy group attached to the parent alkane. Name it by replacing the -yl ending of the corresponding alkyl group’s name with -oxy. Give it a position number. Step 3 Put the prefix and suffix together: alkoxy group + parent alkane. Common Name Step 1 List the alkyl groups that are attached to the oxygen atom, in

alphabetical order. Step 2 Place the suffix -ether at the end of the name.

Chapter 1 Classifying Organic Compounds • MHR

29

Sample Problem Naming an Ether Problem Give the IUPAC name and the common name of the following ether. CH3

CH2

O

CH2

CH3

CH2

Solution IUPAC Name Step 1 The longest alkyl group is based on propane.

CH3

CH2

O

CH2

CH2

CH3

Step 2 The alkoxy group is based on ethane (the ethyl group). It is

located at the first carbon atom of the propane part. Therefore, the prefix is 1-ethoxy-. Step 3 The full name is 1-ethoxypropane. Common Name Step 1 The two alkyl groups are ethyl and propyl. Step 2 The full name is ethyl propyl ether.

Practice Problems 22. Use the IUPAC system to name each ether. (a) H3C

O

CH3

(b) H3C

O

CH

(c) CH3

CH2

CH2

CH2

O

CH3

CH3 CH3 23. Give the common name for each ether. (a) H3C

O

CH2CH3

(b) H3C

O

CH3

24. Draw each ether. (a) 1-methoxypropane

(c) tert-butyl methyl ether

(b) 3-ethoxy-4-methylheptane 25. Sketch diagrams of an ether and an alcohol with the same number of

carbon atoms. Generally speaking, would you expect an ether or an alcohol to be more soluble in water? Explain your reasoning.

Table 1.7 describes some physical properties of ethers. Like alcohols, ethers are polar molecules. Ethers, however, cannot form hydrogen bonds with themselves. The physical properties of ethers depend on these characteristics.

30

MHR • Unit 1 Organic Chemistry

Table 1.7 Physical Properties of Ethers Polarity of functional group The bent shape around the oxygen atom in an ether

means that the two CO dipoles do not counteract each other. Because a CO bond is less polar than an OH bond, an ether is less polar than an alcohol. Hydrogen bonding

Because there is no OH bond in an ether, hydrogen bonding does not occur between ether molecules. Ethers can accept hydrogen bonding from water molecules.

Solubility in water

Ethers are usually soluble in water. The solubility of an ether decreases as the size of the alkyl groups increases.

Melting and boiling points

The boiling points of ethers are much lower than the boiling points of alcohols with the same number of carbon atoms.

Additional Characteristics of Ethers • Like alcohols, ethers are extremely flammable and should be used with caution.

Amines An organic compound with the functional group NH2 , NHR, or NR2 is called an amine. The letter N refers to the nitrogen atom. The letter R refers to an alkyl group attached to the nitrogen. The general formula of an amine is RNR′2. Amines can be thought of as derivatives of the ammonia molecule, NH3 . They are classified as primary, secondary, or tertiary, depending on how many alkyl groups are attached to the nitrogen atom. Note that the meanings of “primary,” “seconday,” and “tertiary” are slightly different from their meanings for alcohols. Figure 1.16 gives some examples of amines. primary amine

secondary amine

tertiary amine

CH3

CH3 CH3

CH2

NH2

A primary amine has one alkyl group and two hydrogen atoms attached to the nitrogen.

CH3

CH2

NH

CH3

A secondary amine has two alkyl groups and one hydrogen atom attached to the nitrogen.

CH2

N

CH2

CH3

A tertiary amine has three alkyl groups attached to the nitrogen atom.

Figure 1.16

To name an amine, follow the steps below. The Sample Problem illustrates how to use these steps to name a secondary amine. How to Name an Amine Step 1 Identify the largest hydrocarbon group attached to the nitrogen atom

as the parent alkane. Step 2 Replace the -e at the end of the name of the parent alkane with

the new ending -amine. Include a position number, if necessary, to show the location of the functional group on the hydrocarbon chain. Step 3 Name the other alkyl group(s) attached to the nitrogen atom. Instead

of position numbers, use the letter N- to locate the group(s). (If two identical alkyl groups are attached to the nitrogen atom, use N,N-.) This is the prefix. Step 4 Put the name together: prefix + root + suffix. Chapter 1 Classifying Organic Compounds • MHR

31

Sample Problem Naming a Secondary Amine Problem Name the following secondary amine. CH3 H3C

NH

CH CH3

Solution

CHEM FA C T

Step 1 The propyl group is the largest of the two hydrocarbon groups

attached to the nitrogen atom. Therefore, the parent alkane is propane.

It is also common and correct to name amines with each alkyl branch listed as an attachment before the suffix -amine. In this system of nomenclature, the molecules in Figure 1.16 are ethylamine, methyl ethyl amine, and methyl diethyl amine. Several other methods of naming amines exist, but they will not be covered in this course.

Step 2 Replacing the -e with -amine gives propanamine. The position

number of the functional group in the propane chain is 2. 1 CH3

H3C

NH

2

CH

3 CH3

Step 3 A methyl group is also attached to the nitrogen atom.

The corresponding prefix is N-methyl-. Step 4 The full name is N-methyl-2-propanamine.

Practice Problems 26. Name each amine. (a) CH3

NH2

(c) CH3

CH2

CH

CH3

NH2

CH3 (b) C(CH3)3CH2

N

CH2CH3

(d)

N

CH3

H 27. Draw a condensed structural diagram for each amine. (a) 2-pentanamine

(c) N-methyl-1-butanamine

(b) cyclohexanamine

(d) N,N-diethyl-3-heptanamine

28. Classify each amine in the previous question as primary, secondary,

or tertiary. 29. Draw and name all the isomers with the molecular formula C4H11N.

32

MHR • Unit 1 Organic Chemistry

Amines are polar compounds. Primary and secondary amines can form hydrogen bonds, but tertiary amines cannot. Table 1.8 lists some common physical properties of amines.

Table 1.8 Physical Properties of Amines Polarity of functional group CN and NH bonds are polar. Thus, amines are

usually polar. Hydrogen bonding

The presence of one or more NH bonds allows hydrogen bonding to take place.

Solubility in water

Because of hydrogen bonding, amines with low molecular masses (four or less carbon atoms) are completely miscible with water. The solubility of an amine decreases as the number of carbon atoms increases.

Melting and boiling points

The boiling points of primary and secondary amines (which contain NH bonds) are higher than the boiling points of tertiary amines (which do not contain an NH bond). The higher boiling points are due to hydrogen bonding between amine molecules.

Additional Characteristics of Amines • Amines are found widely in nature. They are often toxic. Many amines that are produced by plants have medicinal properties. (See Figure 1.17.) • Amines with low molecular masses have a distinctive fishy smell. Also, many offensive odours of decay and decomposition are caused by amines. For example, cadavarine, H2NCH2CH2CH2CH2CH2NH2 , contributes to the odour of decaying flesh. This compound gets its common name from the word “cadaver,” meaning “dead body.” • Like ammonia, amines act as weak bases. Since amines are bases, adding an acid to an amine produces a salt. This explains why vinegar and lemon juice (both acids) can be used to neutralize the fishy smell of seafood, which is caused by basic amines. A

Figure 1.17 (A) Aniline is an aromatic amine that is useful for preparing dyes. (B) Adrenaline is a hormone that is produced by the human body when under stress. (C) Quinine is an effective drug against malarial fever.

B

C

CH

OH OH

NH2 HO

CH

CH CH2

CH3

NH

H3CO

HO aniline (primary amine)

CH2

N

N adrenaline (secondary amine)

quinine (tertiary amine)

Section Summary In this section, you learned how to recognize, name, and draw members of the alcohol, alkyl halide, ether, and amine families. You also learned how to recognize some of the physical properties of these compounds. In the next section, you will learn about families of organic compounds with functional groups that contain the CO bond.

Chapter 1 Classifying Organic Compounds • MHR

33

Section Review 1

K/U

Name each compound. NH2

(a)

(c)

OH H3C

CH3

CH3

Unit Issue Prep

2

K/U

CHCH2CH3

O

(b) CH3CH2

Write the IUPAC name for each compound.

(a) CH3CH2CH2CH2CH2CH2CH2OH

Organic compounds are used in a wide variety of applications all around you. If you want to prepare for your Unit 1 Issue, research the use of organic compounds as fuel, medicines, and food additives.

(b) CH3CH(OH)CH2CH3 (c) CH3CH2NH2 (d) (CH3)2NH (e) CH3CH2OCH3 (f) CH3CH(Cl)CH3 3

C

Draw a condensed structural diagram for each compound.

(a) 3-heptanol (b) N-ethyl-2-hexanamine (c) 3-methoxypentane 4

Draw and name three isomers that have the molecular formula C5H12O.

5

Name the following compounds. Then rank them, from highest to lowest boiling point. Explain your reasoning.

C

I

CH3

(a) H3C

H3C

O

CH3

CH3

CH2

OH CH3

CH2

(b) CH3

CH3

CH3

CH2

CH2

NH2

CH3

N

CH3

6

Draw cyclohexanol and cyclohexane. Which compound do you expect to be more soluble in water? Explain your reasoning.

7

Name the following compounds. Which compound do you expect to be more soluble in benzene? Explain your reasoning.

C

I

OH

8

Name these compounds. Then rank them, from highest to lowest molecular polarity. Explain your reasoning. I

CH3

CH2

CH2

CH3

HO

CH2

CH2

CH2

CH3CH2

34

MHR • Unit 1 Organic Chemistry

O

CH2CH3

CH3