15-1

Chapter 15

Organic Compounds and the Atomic Properties of Carbon

15-2

Organic Compounds and the Atomic Properties of Carbon

15.1 The special nature of carbon and the characteristics of organic molecules

15.2 The structures and classes of hydrocarbons

15.3 Some important classes of organic reactions

15.4 Properties and reactivities of common functional groups

15.5 The monomer-polymer theme I: Synthetic macromolecules

15.6 The monomer-polymer theme II: Biological macromolecules

15-3

Figure 15.1

The position of carbon in the periodic table

15-4

Figure 15.2

The chemical diversity of organic compounds

4 carbons linked with single bonds, 1 oxygen and needed hydrogens.

CH3 CH2 CH2 CH2 OHCH3 CH2 CH CH3

OHCH3 CH2 CH2 O CH3

CH3 CH CH2 OHCH3

CH3 C

OH

CH3

CH3

CH3 CH2 O CH2 CH3

CH3 CH

CH3

O CH3

CH3 CH CH CH3

OH2C

H2C CH CH2OH

H2C

H2C CH CH2OH

CH2

CH2 CH2

CHOH

CH2

CH CH2

O

CH3

H2C

H2C CH2

CH2

O

15-5

CH3 CH2 CH2 C O

H

CH3 CH2 C CH3

O

CH2 CH CH2 CH3

O C

H2C CH CH3

OH

H

Figure 15.2 (continued)

H2C

H2C CH

O

CH3

O

H2C C CH3

CH3

CH2

CH2 CH2

CO

CH2

H2C CH CH

OC

H2C CH CH3

O

CH3 CH C

O

CH3

H

15-6

HYDROCARBONS

Carbon skeletons and hydrogen skins

When determining the number of different skeletons, remember that:

Each carbon forms a maximum of four single bonds, OR twosingle and one double bond, OR one single and triple bond.

The arrangement of carbon atoms determines the skeleton, so a straight chain and a bent chain represent the same skeleton.

Groups joined by single bonds can rotate, so a branch pointing down is the same as one pointing up.

15-7

Some five-carbon skeletons

Figure 15.3

single bonds double bonds ring structures

15-8

Adding a H-atom skin to a carbon skeleton

Figure 15.4

15-9

SAMPLE PROBLEM 15.1 Drawing hydrocarbons

PROBLEM: Draw structures that have different atom arrangements for hydrocarbons with:

PLAN: Start with the longest chain and draw shorter chains until you are repeating structures.

(a) six C atoms, no multiple bonds, and no rings

(b) four C atoms, one double bond, and no rings

(c) four C atoms, no multiple bonds, and one ring

SOLUTION: (a) six carbons, no rings

C C H

H

H

C

H

HH

H

C

H

H

C

H

H

C

H

H

H C

H

H

C

C

H

C

H

H

C

H

H

C

H

H

H H

H

H H

C

H

H

C

H

H

C

H

C

H

H

C

H

H

H H

C

H

H H

15-10

SAMPLE PROBLEM 15.1 (continued)

(a) continued:

CC

C

CC

C

CC

C

CC

C

(b) four carbons, one double bond

C C C CH

H H H

H

H

H

H

C C C CH

H H H

H

H

H

H

H C C C

H H

H

H

C H

H

H

(c) four carbons, one ring

C

C C

C

H

H

H

H

H

H

H

HC

C C

C

H

H

H H

H

H H

H

15-11

Table 15.1 Numerical Roots for Carbon Chains and Branches

number of carbon atomsroots

1

2

3

4

5

6

8

7

9

10

meth-

eth-

prop-

but-

hex-

pent-

hept-

oct-

non-

dec-

15-12

15-13

Figure 15.5

Ways to depict formulas and models of an alkane

15-14

Figure 15.6

Depicting cycloalkanes

C

C C

H H

H

HH

H

C

C C

CH

H

H

H

H

H H

H

cyclopropane cyclobutane

15-15

Figure 15.6

Depicting cycloalkanes

cyclopentanecyclohexane

C C

CC

C

H HH

H

HHH

HH

H C

CC

C

CC

H H

H H

H

HH

H

H

H

HH

15-16

15-17

Figure 15.7

Boiling points of the first 10 unbranched alkanes

15-18

Figure 15.8

An analogy for optical isomers

15-19

Figure 15.9

Two chiral molecules

optical isomers of 3-methylhexane optical isomers of alanine

15-20

Figure 15.10

The rotation of plane-polarized light by an optically active substance

15-21

Figure 15.11

The binding site of an enzyme

15-22

15-23

Figure B15.1

The initial chemical event in vision

15-24

SAMPLE PROBLEM 15.2 Naming alkanes, alkenes and alkynes

PROBLEM: Give the systematic name for each of the following, indicate the chiral center in part (d), and draw two geometric isomers for part (c).

(a)CH3 C

CH3

CH3

CH2 CH3 CH3 CH2 CH CH

CH3

CH3

CH2

CH3

(b) CH3

CH2CH3

(c)

CH3 CH2 CH CH

CH3

CH2

(d)

CH2 CH C CH

CH3

CH3CH3

CH3

(e)

PLAN: For (a)-(c), find the longest, continuous chain and give it the base name (root + suffix). Then number the chain so that the branches occur on the lowest numbered carbons and name the branches with the (root + yl). For (d) and (e) the main chain must contain the double bond and the chain must be numbered such that the double bond occurs on the lowest numbered carbon.

15-25

SAMPLE PROBLEM 15.2

SOLUTION:

(continued)

(a)CH3 C

CH3

CH3

CH2 CH3

butanemethyl

methyl

1 432

2,2-dimethylbutane

CH3 CH2 CH CH

CH3

CH3

CH2

CH3

(b)

hexane

methyl

methyl

1

2

3456

3,4-dimethylhexane

(can be numbered in either direction)

CH3

CH2CH3

(c)

cyclopentane

methyl

ethyl

1

23

45

1-ethyl-2-methylcyclopentane

CH3 CH2 CH CH

CH3

CH2

(d)

methyl

12345

pentene

1-pentene3-methyl-1-pentene

chiral center

15-26

SAMPLE PROBLEM 15.2 (continued)

CH2 CH C CH

CH3

CH3CH3

CH3

(e)methyl

methyl

123456

3-hexene

CH2

C CCH

CH3

CH3CH3

CH3

methyl

methyl

12

34

56

3-hexene

H

cis-2,3-dimethyl-3-hexene

CH2

C CCH

CH3

CH3

CH3

CH3

methyl

methyl

12

34

56

3-hexene

H

trans-2,3-dimethyl-3-hexene

15-27

Figure 15.12

Representations of benzene

or

15-28

Types of organic reactions

An addition reaction occurs when an unsaturated reactant becomes a saturated product:

Elimination reactions are the opposite of addition; they occur when a more saturated reactant becomes a less saturated product:

R CH CH R + X Y R CH CH R

X Y

R CH CH R + X YR CH CH R

X Y

A substitution reaction occurs when an atom (or group) from an added reagent substitutes for one in the organic reactant:

R C X + Y R C Y + X

15-29

Figure 15.13

C C + Br2

A color test for C=C bonds

15-30

C C

Br

Br

15-31

SAMPLE PROBLEM 15.3 Recognizing the type of organic reaction

PROBLEM: State whether each reaction is an addition, elimination, or substitution:

(a) CH3 CH2 CH2 Br CH3 CH CH2 + HBr

(b) + H2

CH3 C Br

O

+ CH3CH2OH

(c)

CH3 C OCH2CH3 + HBr

O

PLAN: Look for changes in the number of atoms attached to carbon.

More atoms bonded to carbon is an addition. Fewer atoms bonded to carbon is an elimination. Same number of atoms bonded to carbon is a substitution.

15-32

SAMPLE PROBLEM 15.3

SOLUTION:

(continued)

(a) CH3 CH2 CH2 Br CH3 CH CH2 + HBr

Elimination: there are fewer bonds to last two carbons.

(b) + H2

Addition: there are more bonds to the two carbons in the second structure.

CH3 C Br

O

+ CH3CH2OH

(c)

CH3 C OCH2CH3 + HBr

O

Substitution: the C-Br bond becomes a C-O bond and the number of bonds to carbon remains the same.

15-33

Figure 15.14

Some molecules with the alcohol functional group

15-34

15-35

15-36

Figure 15.15

General structures of amines

primary (1o) amine secondary( 2o) amine tertiary (3o) amine

C Nthe amine functional group

15-37

Figure 15.16

Some biomolecules with the amine functional group

lysine (1o amine)(amino acid found

in proteins)

adenine (1o amine)(component of nucleic acids)

epinephrine (adrenaline; 2o amine)(neurotransmitter in

brain; hormone released during stress)

cocaine (3o amine)(brain stimulant;

widely abused drug)

15-38

Figure 15.17

Structure of a cationic detergent

CH

N CH3H3C

H2C

CH2

H2C

CH2

H2C

CH2

H2C

CH2

H2C

CH2

H2C

CH2

H2C

CH2

H2C

CH3

Cl

benzylcetyldimethyl-

ammonium chloride

15-39

SAMPLE PROBLEM 15.4 Predicting the reactions of alcohols, alkyl halides, and amines

PROBLEM: Determine the reaction type and predict the product(s) in the following:

(a) CH3 CH2 CH2 I + NaOH

(b) CH3 CH2 Br + 2 H3C CH2 CH2 NH2

H3C CH CH3

OH(c)

Cr2O72-

H2SO4

PLAN: Check for functional groups and reagents, then for inorganics added. In (a) the -OH will substitute in the alkyl halide; in (b) the amine and alkyl halide will undergo a substitution of amine for halogen; in (c) the inorganics form a strong oxidizing agent resulting in an elimination.

15-40

SAMPLE PROBLEM 15.4 (continued)

SOLUTION:

(a) substitution - the products are: CH3 CH2 CH2 OH + NaI

(b) substitution - the products are: CH3 CH2 NHCH2CH2CH3

+ CH3CH2CH2NHBr(c) elimination - the product is: H3C C CH3

O

15-41

Figure 15.18

Some common aldehydes and ketones

methanal (formaldehyde) used to make

resins in plywood, dishware,

countertops; biological

preservative

ethanal (acetaldehyde) narcotic product

of ethanol metabolism;

used to make perfume,

flavors, plastics, other chemicals

benzaldehyde artificial almond

flavoring

2-propanone (acetone) solvent

for fat, rubber, plastic, varnish,

lacquer; chemical

feedstock

2-butanone (methyl ethyl

ketone) important solvent

15-42

Figure 15.19

The carbonyl group

15-43

SAMPLE PROBLEM 15.5

SOLUTION:

Predicting the steps in a reaction sequence

PROBLEM: Fill in the blanks in the following reaction sequence:

CH3 CH2 CH CH3

BrOH- Cr2O7

2-

H2SO4

CH3Li H2O

PLAN: Look at the functional groups and reagents to determine the type of reaction.

CH3 CH2 CH CH3

BrOH-

2-bromobutane

CH3 CH2 CH CH3

OH

2-butanol

Cr2O72-

H2SO4

CH3 CH2 C CH3

O

2-butanone

CH3LiH2O

CH3 CH2 C CH3

OH

CH3

2-methyl-2-butanol

15-44

Figure 15.20

Some molecules with the carboxylic acid functional group

methanoic acid (formic acid) (an irritating

component of ant and bee stings)

butanoic acid (butyric acid)

(odor of rancid butter; suspected component

of monkey sex attractant)

octadecanoic acid (stearic acid)

(found in animal fats; used in making

candles and soap)

benzoic acid (calorimetric

standard; used in preserving food,

dyeing fabric, curing tobacco)

15-45

Figure 15.21

Some lipid molecules with the ester functional group

cetyl palmitate (the most

common lipid in whale blubber)

lecithin(phospholipid found in all cell membranes)

tristearin (typical dietary fat used as an

energy store in animals)

15-46

Figure 15.22

Which reactant contributes which group to the ester?

R C OH

O

R' OH18

+ R C O

O

R'18

+ H O H

R C OH

O

R' OH18

+ R C O

O

R' + H O H18

R C OH

O

H OR'+ R C O

O

R' + H O HH+

General esterification reaction

15-47

lysergic acid diethylamide (LSD-25)

(a potent hallucinogen)

Figure 15.23

Some molecules with the amide functional group

N,N-dimethylmethanamide (dimethylformamide)

(major organic solvent; used in production of

synthetic fibers)

acetaminophen(active ingredient in

nonaspirin pain relievers; used to make dyes and photographic chemicals)

15-48

SAMPLE PROBLEM 15.6

SOLUTION:

Predicting the reactions of the carboxylic acid family

PROBLEM: Predict the product(s) of the following reactions:

CH3 CH2 CH2 C

O

OH CH3 CH CH3

OH

+H+

(a)

CH3 CH CH2 CH2(b)

CH3

C NH

O

CH2 CH3NaOH

H2O

PLAN: (a) An acid and an alcohol undergo a condensation reaction to forman ester.

(b) An amide, in the presence of base and water, is hydrolyzed.

CH3 CH2 CH2 C

O

O(a) CH

CH3

CH3

CH3 CH CH2 CH2(b)

CH3

C NH2

O

CH2 CH3O- + Na+ +

15-49

Figure 15.24

The formation of carboxylic, phosphoric, and sulfuric

acid anhydrides

15-50

Figure 15.25

An ester and an amide of other non-metals

glucose-6-phosphate sulfanilamide

15-51

SAMPLE PROBLEM 15.7

PROBLEM:

SOLUTION:

Recognizing functional groups

Circle and name the functional groups in the following molecules:

(a)C

O

O

OH

C CH3

O(b)

CH

OH

CH2 NH CH3

(c)

Cl

O

PLAN: Use Table 15.5 to identify the functional groups.

(a)C

O

O

OH

C CH3

O

carboxylic acid

ester

(b)

CH

OH

CH2 NH CH3

alcohol

2o amine

(c)

Cl

Oketone

alkene

haloalkane

15-52

Figure 15.26

A summary of the interconversions among the major organic functional groups

15-53

Figure 15.27

Steps in the free-radical polymerization of ethylene

15-54

15-55

15-56

Figure 15.28

The formation of nylon-66

15-57

Figure 15.29

The structure of glucose in aqueous solution and the formation of a disaccharide

15-58

Figure 15.30The common amino acids

15-59

Figure 15.31

A portion of a polypeptide chain

15-60

Figure 15.32

Forces that

maintain protein

structure

15-61

Figure 15.33

collagensilk fibroin

Shapes of

fibrous proteins

15-62

Figure 15.34

mononucleotide of ribonucleic acid (RNA)

mononucleotide of deoxyribonucleic acid

(DNA)

portion of DNA polynucleotide chain

Mononucleotide monomers and their linkage

15-63

Figure 15.35

The double helix of DNA

1.08 nm

1.08 nm

15-64

Figure 15.36

Key stages in protein synthesis

15-65 Figure 15.37

Key stages of DNA replication