15-1 chapter 15 organic compounds and the atomic properties of carbon
TRANSCRIPT
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
15-4
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.
15-9
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-
15-14
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
15-24
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
15-28
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
15-31
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.
15-36
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
15-43
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+ +
15-51
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
15-62
Figure 15.34
mononucleotide of ribonucleic acid (RNA)
mononucleotide of deoxyribonucleic acid
(DNA)
portion of DNA polynucleotide chain
Mononucleotide monomers and their linkage