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11-1
Principles and Applications ofInorganic, Organic, and Biological
ChemistryDenniston, Topping, and Caret
4th ed
Chapter 11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Power Point to Accompany
11-2
Organic Chemistry-HistoryHistorically - compounds from living
systems (plants and animals)A “vital force”, ie. life was thought to be
necessary to make organic chemicals.In 1828 Wohler synthesized urea from
purely inorganic chemicals. Urea, found in urine, was definitely an
organic compound!
CO
NH2 NH2KCNO + NH4Cl + KClurea
11-3
Modern Organic Chemistry
The Study of Carbon Compounds
(some exceptions: for example carbonates, carbon dioxide, etc.)
Biochemistry is now the field that studies chemicals of life.
11-4
Examples of Organic ChemicalsFoods
Carbohydrates
Fats
Proteins
Clothing
silk, linen, wool,
cotton, Dacron,
Nylon, Orlon,
etc.
Plastics
Pharmaceuticals
Detergents and Soaps
Pesticides
Gasoline and oils
Water purification
11-5
11.1 Why is Carbon Unique?
1. Forms four covalent bonds
2. Bonds covalently to: H, O, N, P, S, and all other nonmetals (except noble gases)
3. Carbon atoms join to form:
a. Chains and b. Rings
CH3CH2CH2CH3CH2 CH2
CH2
CH2
CH2
11-6
Why is carbon unique?: 2
4. Carbon can form multiple bonds to itself, oxygen, and nitrogen.
CH2 O
CH2 NH
CH2 CH2
CH CH
CH N
double bonds
triple bonds
11-7
Why is Carbon Unique?: 3
4. Many carbon compounds exist in the form of isomers.
Isomers are compounds with the same molecular formula but different structures.
An isomer example: A, B, and C all are C4H10 but have different structures. See the next slide!
11-8
Why is Carbon Unique?: 3bIsomer Examples. All C4H8
CH2
CH2 CH2
CH2
CH3CH2CH CH2
CH3CH CH CH3
A
B
C
11-9
Organic vs Inorganic: DifferencesOrganic Inorganic
Bonding Covalent Ionic
Physical State
(room temp)
Gas/liquid common
Solids common
Melting points Tend to be low Tend to be very high
Sol. In water Tend to be insoluble
Much higher percent soluble
Conductivity Nonconductors Conduct in soln. and molten
11-10
Families of Compounds: Hydrocarbons
Hydrocarbons contain only carbon and hydrogen.
They are nonpolar molecules and consequently are not soluble in water but are soluble in typical nonpolar organic solvents like toluene or pentane.
Hydrocarbons are constructed of chains or rings of carbon atoms with sufficient hydrogens to fulfill carbons need for four bonds.
11-11
Hydrocarbons
Aliphatics Aromatics
Structures Based On:Chains and Benzene ring
nonbenzenoid
rings
11-12
Hydrocarbons
Aliphatics Aromatics
Alkanes and cycloalkanes
Alkenes and cycloalkenes
Alkynes and cycloalkynes
11-13
Functional groups
Alkanes are compounds that contain only carbon-carbon and carbon-hydrogen single bonds.
For example:
CH2
CH2CH2
CH2
CH2 CH2
CH3 CH3
CH3 CH2 CH3
cyclohexane-a ring alkane
propane-burned in a barbecue grill
ethane
11-14
Functional groups-2
alkenes have a carbon-carbon double bond
alkynes have a carbon-carbon triple bond
CH2 CH2
CH3
CH2CH2
C C
C C
CH2
CH2
CH2CH2
CH2CH2
CH2CH2
H H
H
H
CH2OH
CH CH
female silkworm mothsex attractant
ethene: basis of polyethylene plastics
acetylene-welding gasin oxyacetylene torch
11-15
Functional groups-3alcohols have the general formula:
ROH (R is a carbon group)
ethers have the general formulas:
R-O-R, Ar-O-R, Ar-O-ArAr is also a carbon group but is “aromatic”
phenols have the general formula:
Ar-OH (aromatic only!)
OH
CH3CH2 OH
CH3CH2O CH2CH3
ethanol, drinking alcohol
phenol-an early topicalanesthetic
diethyl ether, a generalanesthetic
aromatic ring
11-16
Functional groups-4aldehydes have the general formula
R1 may be H or any carbon group
ketones have the general formula
neither R1 nor R2 can be H
aldehyde carbonyl
ketone carbonyl
R1 C H
O
R1 C R2
O
H CO
CHOH
CH2OPO32-
CH3C CH2
OCO
Oacetoacetate ion, productof fat metabolism
glyceraldehyde-3-phosphatefrom glucose metabolism
11-17
Functional groups-5carboxylic acids have the general formula
R1 may be carbon or Hesters have the general formula
R1 may be carbon or H but R2 cannot be H or it would be an acid!
ester carbonyl
acid groups
R1 C OHO
R1 CO
OR2
OH
C O
O
CH3
CH2 C
O
OH
C
CH2
OH
C OH
O
CO2H
citric acid, found in fruits
condensedformula
methyl salicylateoil of wintergreen
11-18
Functional groups-6acid chlorides have the general formula
R1 is usually carbon
anhydrides have the general formula
R1 usually is the same as R2 and neither is H
R1 C ClO
R1 C O C R2
O O
ClCO
CH2CH2CH2CH2CO
Cl
CH3CO
OCO
CH3
pivaloyl chloride- used to make nylon
acetic anhydride-used to transferan acetyl group
11-19
Functional groups-7amines have one of these general formulas
R groups may be alkyl or aromatic
amides have the general formula
All Rs may be carbon or H
amine nitrogens
amide bond
R1 NH2 R1 NHR2
R1 NR2
R3
R1 C
O
NR2
R3
N
CH2 CH
NH2
C
O
OH
N C CH3
OH
O
Tryptophan- an essential aminoacid
acetaminophen-theanalgesic found inTylenol (Reg)
11-20
Functional Groups-8thiols (mercaptans) have the general formula
R1 is any carbon group
disulfides have the general formula
R is any carbon groupRs may be different
R1 SH
R S S R
H CNH2
CH2 SHCOOH
H C
NH2
CH2 S
COOH
HC
NH2
CH2S
COOH
cysteine, anamino acidfound incystine-an amino acid
important in3-D structure of proteins.
11-21
Test: Identify the groups 1-91 an amine
2 a carboxylic acid
3 an ester
4 an alkene
5 an aldehyde
6 an alcohol
7 a ketone
8 a thiol
9 an anhydride
NH2
CH C
O
CH3 OH CO
O
CH3
CH3
CH2CHCHCH2
OHCH2
CH
CHCH
CH
C
O
OH
OH
OH
OH
H
CO
CH3
CH2
CH2
CH2 SH
CH3 C O
O
C CH3
O9.
8.
7. 6.
5.4.
3.2.
1.
11-22
11.2 Alkanes, CnH2n+2The title shows the general formula for a
chain alkane.
The first ten alkanes are:
methane CH4 hexane C6H12
ethane C2H6 heptane C7H16
propane C3H8 octane C8H18
butane C4H10 nonane C9H20
pentane C5H12 decane C10 H22
11-23
Lewis vs Condensed Formulas
The Lewis dot and condensed formulas for methane.
The Lewis dot and condensed formulas for ethane .
CH
HHH
CH
CHH
HH
HCH3CH3
CH4
11-24
Drawing Methane and Ethane
C
H
HH
C
H
HH
109.5 o
Staggered form of ethane
H
H
HH
in plane
in front of plane
behind plane
11-25
Lewis vs Condensed Formulas-2Lewis dot vs condensed formulas: propane.
Terminal carbons condense to CH3 with the
hydrogens usually to the right of the carbon. Interior carbons condense to CH2 .
C C C HHH
H
H
H
H
HCH2CH3 CH3
11-26
Lewis vs Condensed Formulas-3A branch or substituent on a chain may be condensed into the chain usually after the carbon from which it branches.
CH3CH(CH3)CHClCH2CH3
H C C C C CH
H H
H
Cl
H
HH
H
H
C HHH
11-27
IUPAC NamesThe IUPAC (International Union of Pure
and Applied Chemistry) is responsible for chemistry names.
Before learning the IUPAC rules for naming alkanes, the names and structures of eight alkyl groups must be learned.
These alkyl groups are historical names accepted by the IUPAC and integrated into modern nomenclature.
11-28
Alkyl Groups
An alkyl group is an alkane with one hydrogen atom removed. It is named by replacing the ane of the alkane name with -yl.
Methane becomes a methyl group.
or CH3H C
H
H
H
H C
H
H
11-29
Alkyl Groups-2
All six hydrogens on ethane are equivalent. Removing one H generates the ethyl group.
CH
CHH
HH
H
CH3CH2
CH3CH2
C2H5
11-30
Alkyl Groups-3Propane: removal of a hydrogen generates two different propyl groups depending on whether an end or center H is removed.
n-propyl isopropyl
CH3CH CH3CH3CH2CH2
CH3 CH2 CH3
11-31
Alkyl Groups-4a
n-butane gives two butyl groups depending on whether an end (1o) or interior (2o) H is removed.
sec-butyln-butyl
CH3 CH2 CH2 CH3
CH3 CH CH2 CH3CH3 CH2 CH2 CH2
11-32
Alkyl Groups-4bIsobutane gives two butyl groups
depending on whether a 10 or 30 H is removed.
isobutyl t-butyl
1o C
3o C
CH3 CH CH3
CH3
CH3 CH CH2
CH3
CH3 C CH3
CH3
11-33
IUPAC Names for Alkanes-1
1. The base or parent name for an alkane is determined by the longest chain of carbon atoms in the formula. Note: the longest chain may bend and twist. It is seldom horizontal!
Any carbon groups not part of the base chain are called branches or substituents.
These carbon groups are also called alkyl groups.
11-34
IUPAC Names for Alkanes-1aRules 1 applied. Find the longest chain in each molecule. (Click for answer.)
A=7 B=8
CH3
CH2
CH2CH2CH CH2CH3
CH3
CH3CH
CH2
CH3
CH2CH
CH2CH2
CH2
CH3
CH3
A
B
11-35
IUPAC Names for Alkanes-22. Number the carbon atoms in the chain
starting from the end with the first branch. If both branches are equally from the ends, continue until a point of difference occurs.
11-36
IUPAC Names for Alkanes-2a
Left: first branch is on carbon 3.Right: first branch is on carbon 3 (From
top) not carbon 4 (If from right).
123
45
6
7
1
2
3 4 5
6 7 8
this branch would be on C-4if you started at correct C-8.
Number the carbon atoms correctly.
CH3
CH2
CH2CH2CH CH2CH3
CH3
CH3CH
CH2
CH3
CH2CH
CH2CH2
CH2
CH3
CH3
11-37
IUPAC Names for Alkanes-33. Prefix the branches/substituents
in alphabetical order before the base/stem name (longest chain). Halogens usually come first.
Indicate the position of the branch on the main chain by prefixing its name with the carbon number to which it is attached. Separate numbers and letters with a hyphen.
11-39
IUPAC Names for Alkanes-3b
Hyphenated and number prefixes are not considered when alphabetizing groups.
Name the compound below.
5-sec-butyl-4-isopropylnonane
CH CHCH3
CH3 CH2 CH2 CH3
CHCHCH3
CH2 CH3
CH2 CH2 CH2 CH3
11-40
IUPAC Names for Alkanes-4
When a branch/substituent occurs more than once, prefix the name with di, tri, tetra,etc. Then prefix the number to the name with a separate number for each occurance. Separate numbers with commas.
eg. 3,4-dimethyl or 4,4,6-triethyl
11-41
IUPAC Names for Alkanes-4a
5-ethyl-2,3-dimethylheptaneethyl>dimethyl
CH3CHCH3 CH CH2CH
CH2CH3
CH3
CH2CH3
Name
11-42
Test: IUPAC Names
6-ethyl-6-isobutyl-3,3-dimethyldecane
CH3CCH3
CH2
CH3
CH2CH2C CH2CH3
CH2
CH CH3CH3
CH2CH2CH2CH3
Name
11-43
Constitutional/Structural Isomers
Constitutional/Structural Isomers differ in how atoms are connected. The two isomers of butane are shown below. The carbon atoms are connected in different patterns.
butaneBp –0.4 oCMp –139 oC
IsobutaneBp –12 oCMp –145 oC
CH3 CH2 CH2 CH3 CH3 CH CH3
CH3
11-44
11.3 CycloalkanesCycloalkanes have two less hydrogens than
the corresponding chain alkane.
Hexane=C6H14; cyclohexane=C6H12
To name cycloalkanes, prefix cyclo to the name of the corresponding alkane.
Place substituents in alphabetical order before the base name as for alkanes.
For multiple substituents, use the lowest possible set of numbers. A single substituent requires no number.
11-45
Cycloalkanes-cont.
Cyclopropane cyclohexane
C C
C
H
H
HH
H
H
CC
C
C C
CH
H H
H
H
HH
H
H H
H H
or
CC
C
C C
CH
Cl H
CH3
H
HH
H
H H
H H
CH3
Clor
1-chloro-3-methyl-cyclohexane
11-46
Cis-trans Isomers in CycloalkanesTwo groups may be on the same side (cis) of
the imagined plane of the cycloring or they may be on the opposite side (trans). The two isomers are referred to geometric or cis-trans isomers. E. g.
cis-1-chloro-3-ethylcyclohexane
trans-1-chloro-3-ethylcyclohexaneCH3
Cl
CH3
Cl
ClCl
Cl
Cl cis-1,4-dichlorolcyclohexane
trans-1,4-dichlorocyclohexane
11-47
11.4 Conformations of AlkanesConformations differ only in rotation about
carbon-carbon single bonds. Two conformations of butane are shown below. The first (staggered form) is more stable because it allows hydrogens to be farther apart and thus the atoms are less crowded.
Insert Fig 11.6
11-48
Two conformations of CyclohexaneChair form Boat form
(more stable)A
E
E
A
AE
E A
E
E
A
A
H HH H
H H
H
H H
H
HH
E=equitorialA=axial
11-49
11.5 Reactions of AlkanesAll alkanes undergo:
Combustion to carbon dioxide and water
Halogenation to haloalkanes
2 C2H6 + 7 O2 4 CO2 + 6 H2O CH3CH3
+Cl2heat orlight CH3CH2Cl +HCl
HH +Br2
heat orlight +HBr
BrH