Transcript AP Notes Chapter 11

AP Notes Chapter 10
Organic Chemistry
Hydrocarbons
Alkanes and
Cycloalkanes
Alkanes
 Alkanes:
hydrocarbons
containing only carboncarbon single bonds
 the
first two alkanes are
methane and ethane
Hydrocarbon: a compound
composed of only carbon
and hydrogen
Alkanes
 the
first 10 alkanes with
unbranched chains
Generic Alkane Formula: CnH2n+2
Constitutional Isomerism
Constitutional isomers:
compounds that have the
same molecular formula but
different structural formulas
(connected differently)
Constitutional Isomerism
CH3 CH2 CH2 CH3
Bu tane
(bp -0.5°C)
CH3
CH3 CHCH3
2-Methylp ropan e
(bp -11.6°C)
Map of Organic Isomerization
Isomers
same different
conn ectivity con nectivity
Stereoisomers
Cons titu tion al Is omers
w ithout with
s tereocenters stereocen ters
Achiral
Cis -Trans Is omers
Chiral
Enantiomers
Dias tereomers
Nomenclature Example
CH3
CH3 CHCH3
1
2
3
2-Methylprop ane
Cycloalkanes
Cyclic hydrocarbon: a
hydrocarbon that
contains carbon atoms
joined to form a ring
Cycloalkanes
Cyclopentane
Cycloh exane
Alkenes and Alkynes

Alkene: a hydrocarbon that contains
one or more carbon-carbon double
bonds

ethylene is the simplest alkene
H
H
C
C
H
H
Ethylene
(an alken e)
H-C
C-H
Acetylen e
(an alk yn e
C
Alkenes and Alkynes

Alkyne: a hydrocarbon that contains
one or more carbon-carbon triple
bonds

acetylene is the simplest alkyne
H
C
H
hylene
alken e)
H-C
C-H
Acetylen e
(an alk yn e)
Alkenes

Cis-trans isomerism

H
because of restricted rotation about a
carbon-carbon double bond, an alkene
with two different groups on each
carbon of the double bond shows cistrans isomerism
H
H
C C
H3 C
CH3
C C
CH3
cis -2-Butene
mp -139°C, b p 4°C
H3 C
H
t rans-2-Butene
mp -106°C, bp 1°C
Benzene and its Derivatives
Aromatic Compounds
 Aromatic
compound: a
hydrocarbon that contains
one or more benzene-like
rings
 arene:
a term used to describe
aromatic compounds
 Ar-: a symbol for an aromatic
group derived by removing an H from an arene
Kekulé structure for benzene
(1872)
The electrons of Benzene are
Delocalized
sp2 hybridized
Nomenclature Example
1
NO2
2
NO2
OH
CH3
3
4
Cl
4-Ch loro-2nitrotoluen e
Br
6
1
5
Br
2
3
4
Br
2,4,6-Trib romoph enol
4
3
2
Br
CH2 CH3
1
2-Bromo-1-ethyl-4n itroben zene
Functional Groups
and Reactions of
Organic
Compounds
Alkanes
 They
burn!
 Hydrocarbon
and Oxygen
yields Carbon
Dioxide and
Water
Reactions of Alkenes:
ADDITION REACTIONS


Alkenes are unsaturated — more
bonds can form to the C atoms
Molecules such as Br2, H2, HCl, HBr,
and H2O add to the double bond
H
C C + Br2
H
H
H
Br Br
H C C H
H H
1,2-dibromoethane
An Addition Reaction
Fat
placed
in Br2
vapor
An Addition Reaction
The fat in bacon is
partially
unsaturated. The fat
adds Br2 to the C=C
bonds.
An Addition Reaction

Fats can be “hydrogenated” with
H2.
Saturated Fats
Peanut butter has partially hydrogenated
vegetable oil.
Reactions of Aromatics
 Substitutions
— not additions
— are typical.
CH3
+ CH3Cl
AlCl3
+ HCl
AlCl3 is a catalyst. Catalysts typically
used in aromatic substitutions.
Functional Groups
See CD-ROM Screens 10.5 & 10.6
Alcohols
Characterized by –OH group [ROH
 Name: add – ol to name of
hydrocarbon

Methanol
Butanol
Structures of Alcohols
C3H5OH: how many structural
isomers?
H
H
H
H
C
C
C
H
H
H
1-propanol
OH
H
H
OH H
C
C
C
H
H
H
H
2-propanol
Add -ol to name of 3-C hydrocarbon.
Indicate position of OH with number.
Alcohol Properties


Alcohols are a derivative of water
Many alcohols dissolve in water
Methanol
dissolves in water.
Butanol is NOT
soluble in water.
“Sterno”

Alcohols burn in
air

A mixture of
ethanol + calcium
acetate = STERNO
GLYCOLS
Alcohols with Two OH Groups
Ethylene
glycol
Propylene
glycol
Alcohol Reactions
Screen 11.6
Substitution
Elimination

Sugars: Related to
Alcohols
Sugars are carbohydrates,
compounds with the formula
Cx(H2O)y.
CHO
H OH
4
HO
HO
H
5
HO
3
H
H
2
HO
1
OH
OH
a-D-glucose
H
H
H
1
OH
2
H
3
OH
4
OH
5
CH 2OH
Open chain form
H OH
4
HO
HO
5
HO
1
3
H
H
2
OH
H
b-D-glucose
OH
Amines
Alcohols are derivatives of H O
(R–OH) and amines are
derivatives of NH3.
Methylamine
Dimethylamine
2
Trimethylamine
Amines
Amines generally have terrible odors!
Cadaverine
Pyridine
Amines
Amines, like NH3, are bases
2 C H NH (aq) + H SO (aq)
6 5
Aniline
2
2
4
2 C H NH (aq) + SO
6 5
3
+
Anilinium ion
4
(aq)
2-
Amines
Nicotine
Many
natural
products
and
drugs
(such as
nicotine
and
cocaine)
are
bases.
Structures of
Aldehydes
Cinnamaldehyde
Odors from
aldehydes and
ketones
O
C
carbonyl group
O
C
H
H
methanal
FORMALDEHYDE
O
C
CH3CH2
H
propanal
O
C
R
H
an ALDEHYDE
O
C
CH3 CH3
dimethylketone
propanone
ACETONE
O
C
CH3
CH2CH2CH3
2-pentanone
O
C
CH3CH2
CH2CH3
3-pentanone
O
C
R
R’
a KETONE
Carboxylic
Acids
Acetic acid
Benzoic acid
Acids are found in
many natural
substances: bread,
fruits, milk, wine
Carboxylic acid group
with acidic H+
All are WEAK acids
Carboxyli
c Acids
Formic acid, HCO2H,
gives the sting to ants.
O
C
OH
H
methanoic acid
FORMIC ACID
O
C
OH
CH3
ethanoic acid
ACETIC ACID
O
C
OH
CH2CH2CH3
butanoic acid
BUTYRIC ACID
O
C
OH
R
a CARBOXYLIC ACID
R
H2N
C
H
O
C
OH
an AMINO ACID
Acids + Alcohols --> ESTERS
Esters have generally pleasant odors
Acids + Alcohols --> ESTERS
O
O
CH 3 COH + CH 3 CH 2 OH
Acetic acid
Ethanol
H+
CH 3 COCH 2 CH 3 + H 2O
Ethyl acetate
Acids + Alcohols --> ESTERS
O
RC — O — H
Carb o xy li c acid
+ R' — O — H
A l co h o l
H+
O
R C — O — R' + H 2 O
Es t er
H
O
Aspirin,
acetylsalicylic acid,
Acid and Ester
C
O
O
C
O
CH3
Fats and Oils
Fats with C=C bonds are usually LIQUDS
Oleic acid: a
monounsaturated
fatty acid
C=C Bond
Fats and Oils
Fats with saturated acids (no C=C bonds)
are SOLIDS.
Saturated fats
are more
common in
animals.
Trans Fatty Acids
Acid
and
Alkene
C=C Bond
Trans Fatty Acids
•Oleic acid is a mono–
unsaturated cis-fatty acid
•Trans fatty acids have
deleterious health effects.
•Trans fatty acids raise plasma
LDL cholesterol and lower HDL
levels.
Acids + Amines --> AMIDES
N-methylacetamide
Acids + Amines --> AMIDES
H
C
H
H
H
O
H
O
C
C
C
C
C
C
N
C
H
H
H
H
Amide link
Acetoaminophen
Tylenol, Datril, Momentum, ...
Polymers


Giant molecules made by joining
many small molecules called
monomers
Average production is 150 kg per
person annually in the U.S.
Polymer
Classifications
 Thermoplastics
(polyethylene) soften and
flow when heated
 Thermosetting plastics —
soft initially but set to solid
when heated. Cannot be
resoftened.
Polymer
Classifications
Other
classification:
plastics, fibers,
elastomers, coatings,
adhesives
Polymer Preparation
 Addition
polymers —
directly adding monomer
units together
 Condensation polymers —
combining monomer units
and splitting out a small
water (water)
Polyethylene:
Addition Polymer
n H2 C
CH2
Ethylene
H
H
C
C
H
H
n
Polyethylene
A polymer with a molar
mass of a million has
about 36,000 units.
Mechanism of
Addition
Polymerization
Initiation
2. Addition
3. Propagation
4. Termination
1.
Addition Polymerization
Types of Polyethylene
Linear, high
density PE (HDPE)
Branched, low
density PE, LDPE
Cross-linked
PE, CLPE
Types of Polyethylene
Polymers based on Substituted Ethylenes, CH2=CHX
CH2CH
OH
CH2CH
n
polyvinyl alcohol
CH2CH
OCCH3 n
O
polyvinyl acetate
n
polystyrene
Table 11.12: others are PVC,
acrylonitrile, polypropylene, polymethyl
methacrylate
Polystyrene


Polystyrene is nonpolar material and
dissolves in organic solvents.
PS foam is mostly air, and when it
dissolves it collapses to a much smaller
volume.
Condensation
Polymers
O
n HOC
O
COH + n HOCH 2CH 2OH
t erephthalic acid
O
C
ethylene glycol
O
COCH 2 CH 2O
+ H2 O
n
Polyethylene t erephthalat e (PET), a polyester
Polyesters, PET
Jackets made from recycled
PET soda bottles
Soda bottles, mylar
film.
Polyesters: Mechanism
Reaction of Diacid and Diol
Polyamides: Nylon
Nylon Rope Trick
Polyamides: Nylon
•Each monomer has 6 C atoms in its chain.
•A polyamide link forms on elmination of HCl
•Result = nylon 66
•Proteins are polyamides
Polymer Recycling
Symbols
LDPE =
Low density PE = 0.910-0.925 g/cm3
HDPE = High density PE = 0.941-0.965
PP =
Polypropylene = 0.90
V=
PVC (Vinyl chloride) = 1.30-1.58