Download Chemistry 101 H Introduction to Organic Chemistry Chapter 6

Chemistry 101 H
Introduction to Organic
Chemistry
Chapter 6 - Introduction to
Organic Chemistry
This presentation was created by
Professor Carl H. Snyder
Chemistry Department
University of Miami
Coral Gables, FL 33124
[email protected]
Copyright 2004 by Carl H. Snyder,
University of Miami. All rights
reserved.
“Organic” in Everyday Life
What do we mean by
organic foods?
organic gardening?
organic pesticides?
“Organic” in Chemistry
“Organic” and “Vital Force”
Before 19th Century, belief was:
Compounds present in plants
and animals required a “vital (life)
force” for their creation.
1828, Friedrich Wohler carried out a
laboratory synthesis of urea, a
biological product formerly believed
to be a product of the “vital force”.
Wohler’s laboratory synthesis of
urea signalled the beginning of the
end of the “vital force” theory.
The Hydrocarbon Family
All organic compounds contain carbon.
If a compound contains carbon, it’s an
organic compound.
Inorganic compounds do not contain carbon.
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Our Most Common Hydrocarbons
Gasoline is our
most common
consumer product
consisting
principally of
hydrocarbons.
Others include:
mineral oil
lubricating oil
petroleum jelly
Methane and The Tetrahedral
Carbon
Methane
Methane, CH4, is the simplest member of
the hydrocarbon family
Four hydrogen atoms form four covalent bonds
with one carbon atom
The Methyl Free Radical
The stereochemistry of methane is tetrahedral.
Four hydrogens lie at the apexes of a tetrahedron.
The carbon lies at the center of the tetrahedron.
The distinguishing characteristic of a free radical is
that it contains an unpaired electron.
Ethane
The 3-Dimensional Structure
of Ethane
The combination of 2 methyl free radicals forms
ethane.
Ethane can be formed in a variety of other ways
as well.
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Three Ways to Draw the
Structure of Ethane
The first shows explicitly the C-C and all
the C-H bonds.
The second shows explicitly only the C-C
bond..
The third is the most common way of
drawing ethane’s structure.
Space-filling Models of
Methane and Ethane
Propane and The Alkanes
methane, CH4
ethane, C2H6
propane, C3H8
are the first 3 members of the alkane family.
All alkanes have the general formula CnH2n+2
From One Methane to One
Ethane
All 4 hydrogens of
methane are mutually
equivalent.
Replacing any one of
methane’s hydrogens
with a methyl group
gives rise to the same
ethane molecule.
From One Ethane to One Propane
Propane - Two Different Kinds
of Hydrogens
The propane molecule
contains two different
kinds of hydrogens:
The methyl group's 6
primary (1o) hydrogens
The methylene group’s 2
secondary (2o) hydrogens
All six of ethane’s hydrogens are mutually equivalent.
Replacing any one of ethane’s hydrogens with a methyl
group gives rise to the same propane molecule.
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From One Propane to Two
Different Butanes
Replacing a 1o
H with a methyl
group gives
butane
Replacing a 2o
H with a methyl
group gives
isobutane.
Isomers
Butane, C4H10 , and isobutane,
C4H10 , are isomers.
The First Five Alkanes - A
Summary
The First 10 Straight-Chain
Alkanes
The C5H12 Alkanes - Structures
Isomeric Alkanes
Left: pentane, the only straight-chain pentane
Center: isopentane, a pentane with one branch
Right: neopentane, a pentane with two branches
By one estimate, there are as many possible
isomers of C100H202 as there are atoms in the
universe.
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IUPAC - #1
IUPAC - #2
IUPAC - #3
IUPAC - #4
IUPAC - #5
Alkenes
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Ethene, or Ethylene
The C-C Single
Bond and The C=C
Double Bond
Covalent bonding in
ethane and in ethene
(ethylene).
Removal of a molecule of hydrogen from
ethane produces ethene (IUPAC), or
ethylene (common).
Where Is The Double Bond?
Give the C=C double
bond the number held by
the lower numbered
carbon.
If the C=C bond lies
between C#1 and C#2,
we have 1-butene.
If between C#2 and
C#3, we have 2-butene.
Alkanes, Alkenes, and Alkynes
A Summary
Alkynes - Ethyne, or
Acetylene
An alkyne contains a
triple bond.
Saturation and Unsaturation
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Saturation and Unsaturation in
Ethane and Ethylene
Addition of H2O to C=C
H2 can be added to C=C double (and triple) bonds.
Water can be added to C=C
The product is an alcohol.
Cycloalkanes
Benzene, An Aromatic
Hydrocarbon
Left: All bonds and all atoms are shown
Center: Only C-C and C=C bonds are shown
Right: The 6 electrons of the C=C system
appear as a circle.
Aromatic Compounds
Some Important Aromatic
Compounds
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The Hydrocarbon Family
A Burning Candle
The Chemistry of a Charcoal
Grill
Balanced Equations
As the carbon of the charcoal briquettes in a
backyard grill burns:
One atom of carbon and one diatomic
molecule of oxygen combine to form one
molecule of carbon dioxide:
1C + 1O2 ---> 1CO2
or more simply
C + O2 ---> CO2
The reaction releases heat.
Carbon dioxide formation:
C + O2 ---> CO2
C + O=O ---> O=C=O
Carbon monoxide formation:
2 C + O2 ---> 2 CO
C, C, O=O ---> CO, CO
End - Chapter 6
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