15-1
Lecture PowerPoint
ChemistryThe Molecular Nature of
Matter and ChangeSixth Edition
Martin S. Silberberg
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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
Bonding Properties of Carbon
• Carbon forms covalent bonds in all its elemental forms and compounds.
– The ground state electron configuration of C is [He]2s22p2; the formation of carbon ions is therefore energetically unfavorable.
– C has an electronegativity of 2.5, which is midway between that of most metals and nonmetals. C prefers to share electrons.
• Carbon exhibits catenation, the ability to bond to itself and form stable chain, ring, and branched compounds.
– The small size of the C atom allows it to form short, strong bonds.
– The tetrahedral shape of the C atom allows catenation.
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Comparison of Carbon and Silicon
• As atomic size increases down the group, bonds between identical atoms become longer and weaker.
– A C–C bond is much stronger than a Si–Si bond.
• The bond energies of a C–C bond, a C–O bond, and a C–Cl bond are very similar.
– C compounds can undergo a variety of reactions and remain stable, while Si compounds cannot.
• Si has low energy d orbitals available for reaction, allowing Si compounds to be more reactive than C compounds.
15-7
Diversity and Reactivity of Organic Molecules
• Many organic compounds contain heteroatoms, atoms other than C and H.
– The most common of these are O, N, and the halogens.
• Most reactions involve the interaction of electron rich area in one molecule with an electron poor site in another.
– C–C bonds and C–H bonds tend to be unreactive.
– Bonds between C and a heteroatom are usually polar, creating an imbalance in electron density and providing a site for reactions to occur.
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Figure 15.2 Heteroatoms and different bonding arrangements lead to great chemical diversity.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Carbon Skeletons
Each C atom can form a maximum of 4 bonds.
Groups joined by a single bond can rotate, so there are often several different arrangements of a given carbon skeleton that are equivalent:
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Drawing Carbon Skeletons
Each C atom can form a maximum of four bonds.These may be four single bonds, OR one double and two single bonds, OR one triple and one single bond.
The arrangement of C atoms determines the skeleton, so a straight chain and a bent chain represent the same skeleton.
Groups joined by a single bond can rotate freely, so a branch pointing down is the same as one point up.
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Figure 15.4 Adding the H-atom skin to the C-atom skeleton.
A C atom single-bonded to one other atom gets three H atoms.
C C
H
H
HA C atom single-bonded to two other atoms gets two H atoms.
C C
H
C
H
A C atom single-bonded to three other atoms gets one H atom.
C C
H
C
C
A C atom single-bonded to four other atoms is already fully bonded (no H atoms).
C C C
C
C
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Figure 15.4 continued
A double-bonded C atom is treated as if it were bonded to two other atoms.
C C H
H
A double- and single-bonded C atom or a triple-bonded C atom is treated as if it were bonded to three other atoms.
C C
H
C
C C H
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Sample Problem 15.1 Drawing Hydrocarbons
PLAN: In each case, we draw the longest carbon chain first and then work down to smaller chains with branches at different points along them. Then we add H atoms to give each C a total of four bonds.
PROBLEM: Draw structures that have different atom arrangements for hydrocarbons with
(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
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Sample Problem 15.1
(a) Six carbons, no rings
H C C C C C C
H
H
H
H
H
H
H
H
H
H
H
H
H6-C chain
H C C C C C H
H
H
HC
H
H
H
H
H H
HH
H
5-C chain
H C C C C H
H
H
HC
C
H
H H
HH
H
H H
H
C C C C H
H
H
H
C
C
HH H
H
H
H
H
H H
H
4-C chains
H C C C C C H
H
H
H
C
H
H
H
H
H
HH H
H
5-C chain
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Sample Problem 15.1
(b) Four C atoms, one double bond, and no rings
H C
H
H
C C
H
H
CH H
H
3-C chain
H C C C C
H
H
H H H
H
H
C C
H
H
H
H
H
C C H
HH
4-C chains
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Sample Problem 15.1
(c) Compounds with four C atoms and one ring
C C
CC
H
H
H
H
H
H
H
H
C C
C
H H
C
H
H
HHH
H
15-18
Alkanes
Hydrocarbons contain only C and H. Alkanes are hydrocarbons that contain only single bonds and are referred to as saturated hydrocarbons.
The general formula for an alkane is CnH2n+2, where n is any positive integer.
Alkanes comprise a homologous series, a group of compounds in which each member differs from the next by a –CH2– group.
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Naming Organic Compounds
The root name of the compound is determined from the number of C atoms in the longest continuous chain.
The name of any organic compound is comprised of three portions:
PREFIX + ROOT + SUFFIX
The prefix identifies any groups attached to the main chain.
The suffix indicates the type of organic compound, and is placed after the root.The suffix for an alkane is –ane.
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Table 15.1 Numerical Roots for Carbon Chains and Branches
Roots Number of C Atoms
meth- 1
eth- 2
prop- 3
but- 4
pent- 5
hex- 6
hept- 7
oct- 8
non- 9
dec- 10
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Figure 15.5 Ways of depicting the alkane 3-ethyl-2-methylhexane.
C C C C C
H
H
H
C
C
HH H
C
H
H
H
H H
H
H H
H
C
H
H
H
H
H
Expanded formula
CH3 CH
CH3
CH
CH2
CH3
CH2 CH2 CH3
Condensed formula
Carbon-skeleton formula Ball-and-stick model Space-filling model
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Figure 15.6 Depicting cycloalkanes.
Cyclopropane
C
C C
H H
H
H
H
H
Cyclobutane
C
C C
C
H
H H
H
H
H
H
H
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Cyclopentane
C
C C
CC
H H
H
H
H
HHH
H
H
Cyclohexane
C
CC
C
CC
H H
H H
H
H
H
H
H
H
H
Figure 15.6 Depicting cycloalkanes.
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Constitutional Isomers
Constitutional or structural isomers have the same molecular formula but a different arrangement of the bonded atoms.
A straight-chain alkane may have many branched structural isomers.
Structural isomers are different compounds and have different properties.If the isomers contain the same functional groups, their properties will still be similar.
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Figure 15.7 Formulas, molar masses (in g/mol), structures, and boiling points (at 1 atm pressure) of the first 10 unbranched alkanes.
Alkanes are nonpolar and their physical properties are determined by the dispersion forces between their molecules.
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Chiral Molecules
Stereoisomers are molecules with the same arrangement of atoms but different orientations of groups in space.
Optical isomers are mirror images of each other that cannot be superimposed.
A molecule must be asymmetric in order to exist as a pair of optical isomers. An asymmetric molecule is termed chiral.Typically, a carbon atom is a chiral center if it is bonded to four different groups.
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Figure 15.8 An analogy for optical isomers.
If two compounds are mirror images of each other that cannot be superimposed, they are called optical isomers.
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Figure 15.9 Two chiral molecules.
optical isomers of 3-methylhexane
optical isomers of alanine
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Optical Activity
Optical isomers have identical physical properties, except that they rotate the plane of polarized light in opposite directions.
A chiral compound is optically active; i.e., it rotates the plane of polarized light.
A compound that rotates the plane of light clockwise is called dextrorotatory, while a compound that rotates the plane of light counterclockwise is called levorotatory.
In their chemical properties, optical isomers differ only in a chiral (asymmetric) environment.
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Figure 15.11 The binding site of an enzyme.
An enzyme provides a chiral environment and therefore distinguishes one optical isomer from another. The shape of one optical isomer fits the binding site, but the mirror image shape of the other isomer does not.
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Naproxen
Many drugs are chiral molecules. One optical isomer has a certain biological activity while the other has a different type of activity or none at all.
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Alkenes
A hydrocarbon that contains at least one C=C bond is called an alkene.
Alkenes are unsaturated and have the general formula CnH2n.
To name an alkene, the root name is determined by the number of C atoms in the longest chain that also contains the double bond.The C chain is numbered from the end closest to the double bond.The suffix for alkenes is –ene.
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Geometric Isomers
The double bond of an alkene restricts rotation, so that the relative positions of the atoms attached to the double bond are fixed.
Alkenes may exist as geometric or cis-trans isomers, which differ in the orientation of the groups attached to the double bond.
Geometric isomers have different physical properties.
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Alkynes
An alkyne is a hydrocarbon that contains at least one CΞC triple bond.
Alkynes have the general formula CnH2n-2 and they are also considred unsaturated carbons.
Alkynes are named in the same way as alkenes, using the suffix –yne.
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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 (e).
CH3 C
CH3
CH3
CH2 CH3
(a) (b)
CH3 CH2 CH
CH3
CH
CH2
CH3
CH3
(c)
(d)
CH3 CH2 CH
CH3
CH CH2
(e)
CH3 CH2 CH C
CH3
CH CH3
CH3
PLAN: For (a) to (c), we find the longest continuous chain (root) and add the suffix –ane because there are only single bonds. Then we name the branches, numbering the C chain from the end closest to the first branch. For (d) and (e) the longest chain must include the double bond.
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Sample Problem 15.2
SOLUTION:
2,3-dimethylbutane
(b)
CH3 CH2 CH
CH3
CH
CH2
CH3
CH3
methyl
1
23456
hexane
methyl
3,4-dimethylhexanemethyl
12
34
5
(c)
ethyl
1-ethyl-2-methylcyclopentane
CH3 C
CH3
CH3
CH2 CH3
(a)
butane
methyl
methyl1 2 3 4
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Sample Problem 15.2
3-methyl-1-pentene
(d)
CH3 CH2 CH
CH3
CH CH2
methyl
12345
chiral center
1-pentene
(e)
12
3456
C CCH3
CH
H
CH2
CH3
CH3CH3
12
34
56 C CCH3
CH
CH2
H
CH3
CH3
CH3
methyl
methyl
methyl
methyl
3-hexene
cis-2,3-dimethyl-3-hexene trans-2,3-dimethyl-3-hexene
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Figure 15.13 Representations of benzene.
Resonance forms having alternating single and double bonds.
or
Resonance hybrid shows the delocalized electrons as either an unbroken or a dashed circle.
Benzene is an aromatic hydrocarbon.
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methylbenzene(toluene)
bp = 110.6°C
1,2-dimethylbenzene(o-xylene)
bp = 144.4°C
1,3-dimethylbenzene(m-xylene)
bp = 139.1°C
1,4-dimethylbenzene(p-xylene)
bp = 138.3°C
O2N NO2
NO2
2,4,6-trinitromethylbenzene(trinitrotoluene, TNT)
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Tools of the Laboratory Nuclear Magnetic Resonance (NMR) Spectroscopy
Figure B15.1 The basis of proton spin resonance.
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Tools of the Laboratory
Figure B15.2 The 1H-NMR spectrum of acetone.
Nuclear Magnetic Resonance (NMR) Spectroscopy
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Tools of the Laboratory
Figure B15.3 The 1H-NMR spectrum of dimethoxymethane.
Nuclear Magnetic Resonance (NMR) Spectroscopy
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Tools of the Laboratory
Figure B15.4 An MRI scan showing a brain tumor.
Nuclear Magnetic Resonance (NMR) Spectroscopy
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Types of Organic Reactions
An addition reaction occurs when an unsaturated reactant becomes a saturated product:
R CH CH R + X Y R CH CH R
X Y
The C=C, CΞC, and C=O bonds commonly undergo addition reactions.In each case, it is the π bond that breaks, leaving the σ bond intact.
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CH2 CH2 + H Cl H CH2 CH2 Cl
Reactants (bonds broken)
1 C=C = 614 kJ
4 C–H = 1652 kJ
1 H–Cl = 427 kJ
Total = 2693 kJ
Products (bonds formed)
1 C–C = -347 kJ
5 C–H = -2065 kJ
1 C–Cl = -339 kJ
Total = -2751kJ
H°rxn = H°bonds broken + H°bonds formed = 2693 kJ + (-2751 kJ) = -58 kJ
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15-51
Figure 15.14 A color test for C=C bonds.
This compound has no C=C bond, so the Br2 does not react.
C C + Br2 C C
Br
Br
Br2 (in pipet) reacts with a compound that has a C=C bond, and the orange-brown color of Br2 disappears.
15-52
Types of Organic Reactions
An elimination reaction occurs when a saturated reactant becomes an unsaturated product.This reaction is the reverse of addition.
The groups typically eliminated are H and a halogen atom or H and an –OH group.
R CH CH R + X YR CH CH R
X Y
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The driving force for an elimination reaction is the formation of a small, stable molecule such as HCl (g) or H2O.
R CH CH R + H OHR CH CH R
OH HH2SO4
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Types of Organic Reactions
A substitution reaction occurs when an atom or group from an added reagent substitutes for one attached to a carbon in the organic reagent.
The C atom at which substitution may be saturated or unsaturated, and X and Y can be many different atoms.
R C X + Y R C Y + X
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CH3 C
O
Cl + HO CH2 CH2 CH
CH3
CH3 CH3 C
O
O CH2 CH2 CH
CH3
CH3
+ H Cl
The main flavor ingredient in banana oil is formed through a substitution reaction:
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Sample Problem 15.3 Recognizing the Type of Organic Reaction
PLAN: We determine the type of reaction by looking for any change in the number of atoms bonded to C.
• An addition reaction results in more atoms bonded to C.• An elimination reaction results in fewer atoms bonded to C.•If there are the same number of atoms bonded to C, the reaction is a substitution.
PROBLEM: State whether each reaction is an addition, elimination, or substitution:
CH3 CH2 CH2 Br CH3 CH CH2 + HBr(a)
(c) CH3 C
O
Br + CH3CH2OH CH3 C
O
OCH2CH3 + HBr
(b) + H2
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Sample Problem 15.3
SOLUTION:
CH3 CH2 CH2 Br CH3 CH CH2 + HBr(a)
This is an elimination reaction; two bonds in the reactant, C–H and C –Br, are absent in the product.
(b) + H2
This is an addition reaction; two more C–H bonds have formed in the product.
(c) CH3 C
O
Br + CH3CH2OH CH3 C
O
OCH2CH3 + HBr
This is a substitution reaction; the reactant C–Br bond has been replaced by a C–O bond in the product.
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Functional Groups
Organic compounds are classified according to their functional groups, a group of atoms bonded in a particular way.
The functional groups in a compound determine both its physical properties and its chemical reactivity.
Functional groups affect the polarity of a compound, and therefore determine the intermolecular forces it exhibits.
Functional groups define the regions of high and low electron density in a compound, thus determining its reactivity.
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Alcohols
The alcohol functional group consists of a carbon bonded to an –OH group.
C O H
Alcohols are named by replacing the –e at the end of the parent hydrocarbon name with the suffix –ol.
Alcohols have high melting and boiling points since they can form hydrogen bonds between their molecules.
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Reactions of Alcohols
Alcohols undergo elimination and substitution reactions.OH
H+
cyclohexanol cyclohexene
+ H2O dehydration (elimination)
CH3 CH2 CH
OH
CH3
K2Cr2O7
H2SO4
CH3 CH2 C
O
CH3
OH O
2-butanol 2-butanone
oxidation (elimination)
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Haloalkanes
Haloalkanes or alkyl halides contain a halogen atom bonded to carbon.
Haloalkanes are named by identifying the halogen with a prefix on the hydrocarbon name. The C bearing the halogen must be numbered.
C X
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Reactions of Haloalkanes
Haloalkanes undergo substitution and elimination reactions.
CH3 CH2 CH2 CH2 Br + OH- CH3 CH2 CH2 CH2 OH + Br-
1-bromobutane 1-butanol
CH3 C
CH3
Cl
CH3 CH3 CH2 O-K++ CH3 C
CH3
CH2 + KCl + CH3 CH2 OH
2-chloro-2-methylpropane
potassium ethoxide 2-methylpropene ethanol
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Amines
The amine functional group contains a N atom.
The systematic name for an amine is formed by dropping the final –e of the alkane and adding the suffix –amine.
C N
Common names that use the name of the alkyl group followed by the suffix –amine are also widely used.
CH3CH2NH2
ethanamine ORethylamine
CH3CH2 NH CH2CH3
diethylamine
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Figure 15.17 General structures of amines.
Amines are classified according to the number of R groups directly attached to the N atom.
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Figure 15.18 Some biomolecules with the amine functional group.
Lysine (1° amine)amino acid found in proteins
Adenine (1° amine)component of nucleic acids
Epinephrine (adrenaline; 2° amine)neurotransmitter in brain; hormone released during stress
Cocaine (3° amine)brain stimulant; widely abused drug
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Properties and Reactions of Amines
Primary and secondary amines can form H bonds; therefore they have higher melting and boiling points than hydrocarbons or alkyl halides of similar mass.
Amines of low molar mass are fishy smelling, water soluble, and weakly basic.
Tertiary amines cannot form H bonds between their molecules because they lack a polar N–H bond.
Amines undergo a variety of reactions, including substitution reactions.
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Sample Problem 15.4 Predicting the Reactions of Alcohols, Alkyl Halides, and Amines
PLAN: We first determine the functional group(s) of the reactant(s) and then examine any inorganic reagent(s) to decide on the reaction type. Keep in mind that, in general, these functional groups undergo substitution or elimination.
PROBLEM: Determine the reaction type and predict the product(s) for each reaction:
(a) CH3 CH2 CH2 I + NaOH
(b) CH3 CH2 CH2 Br + 2 CH3 CH2 CH2 NH2
(c) CH3 CH
OH
CH3
Cr2O72-
H2SO4
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SOLUTION:
Sample Problem 15.4
(a) In this reaction the OH of the NaOH reaction substitutes for the I in the organic reagent:
CH3 CH2 CH2 OH + NaI
(b) This is a substitution reaction:
CH3 CH2 CH2 NH
CH2CH3
+ CH3 CH2 CH2 NH2Br
(c) This is an elimination reaction since acidic Cr2O72- is a strong
oxidizing agent:CH3 C
O
CH3
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Alkenes
Alkenes contain the C=C double bond:
Alkenes typically undergo addition reactions. The electron-rich double bond is readily attracted to the partially positive H atoms of H3O+ ions and hydrohalic acids.
C C
CH3
C CH2CH3 + H3O+
CH3
C CH3CH3
OH
OH
+ H+
2-methylpropene 2-methyl-2-propanol
15-74
Aromatic Hydrocarbons
Benzene is an aromatic hydrocarbon and is a resonance hybrid. Its bond electrons are delocalized.
Aromatic compounds are unusually stable and although they contain double bonds they undergo substitution rather than addition reactions.
+ Br2
FeBr3
Br
+ HBr
benzene bromobenzene
15-75
Figure 15.19 The stability of benzene.
Benzene releases less energy during hydrogenation than expected, because it is already much more stable than a similar imaginary alkene.
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Aldehydes and Ketones
Aldehydes and ketones both contain the carbonyl group, C=O.
Aldehydes are named by replacing the final –e of the alkane name with the suffix –al.
Ketones have the suffix –one and the position of the carbonyl must always be indicated.
R and R′ indicate hydrocarbon groups.
H C
O
Raldehyde
R C
O
R'ketone
15-77
Figure 15.20 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 perfumes, flavors, plastics, other chemicals
2-Propanone (acetone) Solvent for fat, rubber, plastic, varnish, lacquer; chemical feedstock
2-Butanone (methyl ethyl ketone) Important solvent
Benzaldehyde Artificial almond flavoring
15-78
Figure 15.21 The polar carbonyl group.
The C=O bond is electron rich and is also highly polar. It readily undergoes addition reactions, and the electron-poor C atom attracts electron-rich groups.
15-79
Reactions of Aldehydes and Ketones
Reduction to alcohols is an example of an addition reaction:
O
reduction
OH
cyclobutanone cyclobutanol
Organometallic compounds, which have a metal atom covalently bonded to C, add to the electron-poor carbonyl C:
R C
O
H + R' Li+-
+
-
R CH
OH
R' + LiOH
15-80
Sample Problem 15.5 Predicting the Steps in a Reaction Sequence
PLAN: For each step we examine the functional group of the reactant and the reagent above the yield arrow to decide on the most likely product.
PROBLEM: Fill in the blanks in the following reaction sequence:
CH3 CH2 CH
Br
CH3OH- Cr2O7
2-
H2SO4
CH3-Li H2O
SOLUTION: The first step involves an alkyl halide reacting with OH-, so this is probably a substitution reaction, which yields an alcohol. In the next step the alcohol is oxidized to a ketone and finally the organometallic reagent adds to the ketone to give an alcohol with one more C in its skeleton:
15-81
Sample Problem 15.5
CH3 CH2 CH
Br
CH3OH- Cr2O7
2-
H2SO4
CH3-Li
H2O
CH3 CH2 CH
OH
CH3
substitution oxidation(elimination)
CH3 CH2 C
O
CH3
addition
CH3 CH2 C
OH
CH3
CH3
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Carboxylic Acids
Carboxylic acids are named by replacing the –e of the alkane with the suffix –oic acid.
Carboxylic acids contain the functional group –COOH, or
Carboxylic acids are weak acids in water, and react with strong bases:
C
O
OH
CH3 C
O
OH (l) + NaOH (aq) CH3 C
O
O- (aq) + Na+ (aq) + H2O (l)
methanoic acid methanoate anion
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Figure 15.22 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 soaps
Benzoic acid Calorimetric standard; used in preserving food, dyeing fabric, curing tobacco
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Esters
The ester group is formed by the reaction of an alcohol and a carboxylic acid.
Ester groups occur commonly in lipids, which are formed by the esterification of fatty acids.
CH3 C
O
OH O CH3H+ CH3 C
O
O CH3 + HOH
ethanoic acid methanol methyl ethanoate
Esterification is a dehydration-condensation reaction.
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Figure 15.23 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
15-86
Saponification
Ester hydrolysis can be carried out using either aqueous acid or aqueous base. When base is used the process is called saponification.This is the process used to make soaps from lipids.
R C
O
O CH2
CH
CH2O
O
C
O
R"
C
O
R'
a triglyceride
3NaOH
HO CH2
CH
CH2HO
HO
R C
O
O- Na+
R' C
O
O- Na+
R" C
O
O- Na+
3 soaps(salts of fatty acids)
glycerol
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Amides
An amide contains the functional group:
C
O
N
Amides, like esters, can be hydrolyzed to give a carboxylic acid and an amine.
The peptide bond, which links amino acids in a protein, is an amide group.
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Lysergic acid diethylamide (LSD-25)A potent hallucinogen
Figure 15.24 Some molecules with the amide functional group.
N,N-Dimethylmethanamide (dimethylformamide)Major organic solvent; used in production of synthetic fibers
AcetaminophenActive ingredient in nonaspirin pain relievers; used to make dyes and photographic chemicals
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Sample Problem 15.6 Predicting the Reactions of the Carboxylic Acid Family
PROBLEM: Predict the product(s) of the following reactions:
(a) CH3 CH2 CH2 C
O
OH CH3 CH
OH
CH3+H+
(b) CH CH2 CH2 C
O
NH
CH3
CH3 CH2CH3
NaOH
H2O
PLAN: We identify the functional groups in the reactant(s) and see how they change. In (a), a carboxylic acid reacts with an alcohol, so the reaction must be a substitution to form an ester. In (b), an amide reacts with aqueous base, so hydrolysis occurs.
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Sample Problem 15.6
SOLUTION:
(a) CH3 CH2 CH2 C
O
OH CH3 CH
OH
CH3+H+
CH3 CH2 CH2 C
O
O CH
CH3
CH3
+ H2O
(b) CH CH2 CH2 C
O
NH
CH3
CH3 CH2CH3
NaOH
H2OCH CH2 CH2 C
OCH3
CH3 O- Na+
CH2CH3
+NH2
15-91
Figure 15.25 The formation of carboxylic, phosphoric, and sulfuric acid anhydrides.
P and S form acids, anhydrides and esters that are analogous to organic compounds.
15-93
Functional Groups with Triple Bonds
Alkynes contain the electron rich –CΞC– group, which readily undergoes addition reactions:
C CHCH3
H2
propyne
CH CH2CH3
propene
H2CH2 CH3CH3
propane
Nitriles contain the group –CΞN and are made by a substution reaction of an alkyl halide with CN- (cyanide):
CH2 ClCH3 + NaCN CH2 CCH3 N + NaCl
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Sample Problem 15.7
SOLUTION:
Recognizing Functional Groups
PLAN: Use Table 15.5 to identify the various functional groups.
PROBLEM: Circle and name the functional groups in the following molecules:
(a)C
O
OH
O C
O
CH3
(b)
CH
OH
CH2 NH CH3
(c) O
Cl
(a)C
O
OH
O C
O
CH3
(b)
CH
OH
CH2 NH CH3
(c) O
Cl
carboxylic acidester
aromatic ring
aromatic ring
alcohol
2° amine
ketone
alkenehaloalkane
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Polymers
Addition polymers, also called chain-growth polymers form when monomers undergo an addition reaction with each other.The monomers of most addition polymers contain an alkene group.
Condensation polymers are formed when monomers link by a dehydration-condensation type reaction.The monomers of condensation polymers have two functional groups, and each monomer can link to two others.
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Figure 15.28 The formation of nylon-66.
Nylon-66 is a condensation polymer, made by reacting a diacid with a diamine. The polyamide forms between the two liquid phases.
HO C
O
(CH2)4 C
O
OH + nH2N (CH2)6 NH2
HO C
O
(CH2)4 C
O
NH (CH2)6 NH Hn
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Figure 15.29 The structure of glucose in aqueous solution and the formation of a disaccharide.
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Chemical Connections
Figure B15.5 Nucleoside triphosphate monomers.
Chemical Connections
Figure B15.5 Nucleoside triphosphate monomers.