Download Organic Chemistry

Organic Chemistry 101
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Carbon Bonding
• Organic Chemistry – Branch of chemistry
dealing with hydrocarbons and their
derivatives.
• Carbon Chain – Carbon atoms chemically
linked to one another, forming a string-like
molecular sequence.
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Hydrocarbons
• The carbon chain forms a “backbone” to
which many other atoms and/or functional
groups can be added.
• Carbon’s ability to form multiple bonds is
responsible for the tremendous number of
organic compounds.
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Terms to Know
• Alkanes – hydrocarbons containing only
single covalent bonds.
• Saturated Hydrocarbons – Hydrocarbons
consisting of molecules in which each carbon
atom is bonded to four other atoms.
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More Alkane Terms
• Straight-chain alkane – Alkane consisting of
molecules in which each carbon atom is
linked to no more than two other C atoms.
• Branched-chain alkane – Alkane in which at
least one carbon atom is bonded to three or
four other carbon atoms.
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• Isomers – Compounds with the same
molecular formula, but different structural
formulas.
• Not to be confused with isotopes.
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Guidelines for naming branched
chained alkanes
• 1. Locate the longest continuous carbon chain.
This designates the parent chain and the root word
of the molecule.
• 2. Number the parent chain such that the branch
(substituent) falls on the lowest carbon number.
• 3. Count the number of carbons in the branched
chain. Use the same set of root words EXCEPT add
the suffix –yl.
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• 4. Designate the location of the branched group by
placing the number followed by a hyphen before
the name of the branched group. The name of the
branched chain serves as the prefix of the parent
chain.
• 5. If there are more than one substituent,
designate the position of every group and
alphabetize the substituents.
• 6. If there is more than one of the same branch on
a chain, designate the positions of the substituent
and name the branch with the additional prefix
indicating how many times it occurs.
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Beyond Alkanes
• Saturated hydrocarbon – hydrocarbon
consisting of molecules in which each carbon
is bonded to four other atoms.
• Unsaturated compound – organic compound
containing one or more double or triple
bonds per molecule.
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Alkenes
• Alkene – hydrocarbon containing a double
covalent bond.
–Ethene, propene, butene, pentene, etc.
–Because of their double bonds, alkenes are
much more reactive than alkanes.
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Naming of Alkenes & Alkynes
• 1. Identify the longest carbon chain that contains
the multiple bond.
• 2. Number the carbons such that the double or
triple bond falls on the lowest carbon number.
• 3. The first carbon atom involved in the bond is
followed by a hyphen and placed in front of the
parent name.
• 4. Name the branches as described in alkanes.
Branches are prefixes in the name.
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Alkynes
• Alkyne – hydrocarbon containing a triple
covalent bond.
–Ethyne, propyne, butyne, pentyne, etc.
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More Organic Molecules
• In addition to straight-chain and branchedchain alkanes and alkenes, there are also ring
structures.
–Imagine taking a hydrogen off of each end
of a hexane molecule and a new bond
forming between the end carbons.
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H H H H H H
H C C C C
Cyclohexane
C C H
H H H H H H
H HH H
H C C H
C H
H C
H C
H
C H
H
H
H
H
H
H
H
H
H
H
H H
H
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Cycloalkanes
• Cyclohexane is one member of a much larger
group of saturated hydrocarbons with ring
structures called cycloalkanes.
• This group includes cyclopropane (C3H6) all
the way up to an infinite number of carbons
in theory.
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Cycloalkenes
• If a double bond is present in a hydrocarbon
ring it is considered to be a cycloalkene.
• The naming process is simple for alkane and
alkene rings: just add a cyclo- prefix to their
name(s).
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Aromatic Compounds
• Aromatic compound – ringlike compounds
such as benzene that can be represented as
having alternating double and single bonds
between carbon atoms.
• These compounds were named so because
the first of their kind discovered had
pleasant odors.
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Aromatic Compounds
• These compounds are considered to be
unsaturated.
• The simplest aromatic compound is benzene
(C6H6).
• While the original structure proposed for
benzene showed alternating double bonds,
most now think all bonds are equal – 1.5
bonds?
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Benzene
• Most people now draw benzene with a circle
in the center to illustrate a “delocalized”
electron system with all six carbons sharing
the extra electrons.
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Organic Molecules With Oxygen
• Functional Group(s) – atom or group of
atoms that impart(s) characteristic
properties to an organic compound.
• In this section we will focus on functional
groups that contain oxygen.
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Organic Compounds
• When discussing organic compounds, the
functional group is usually the focus and we
don’t really care much about the rest of the
molecule.
• We use the letter “R” the stand for the REST
of the molecule.
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Alcohols (& Phenols)
• Alcohols and phenols are organic molecules
that contain a hydroxyl group.
• Hydroxyl Group – A hydrogen bonded to an
oxygen that is covalently bonded to the rest
of the molecule.
• We abbreviate: R-OH
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Alcohols (& Phenols)
• Just as with naming other alkanes and
alkenes, the location of the hydroxyl group is
determined by numbering the molecule such
that the hydroxyl group has the lowest
number possible.
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Alcohols (& Phenols)
H
H C O H
OH
H
methanol
(methyl alcohol)
phenol
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Ethers
• Ethers are very similar to alcohols except,
instead of an oxygen being bonded to a
carbon on one side and a hydrogen on the
other, an ether’s oxygen is single-bonded to a
carbon on each side.
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Ethers
• Ethers are named by saying the name of the
carbon group on each side followed by the
word “ether”.
• No numbering is necessary.
• We abbreviate: R-O-R’
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Ethers
H
H H
H C O C
H
C
H
H H
methyl ethyl ether
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Aldehydes
• Aldehydes contain a carbonyl functional
group whose carbon is attached to a
hydrogen on one side and a carbon on the
other side.
• Carbonyl group – A carbon double-bonded
to an oxygen is a carbonyl group.
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Aldehydes
• Aldehydes are named with an
“-al” ending.
• Numbering (for location) of the carbonyl
group is not necessary in the name because
it is always located at the end.
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Aldehydes
H O
H C
C
H
H
ethanal
(acetaldehyde)
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Ketones
• Ketones are compounds in which the carbon
in the carbonyl group is bonded to two
carbons.
• Ketones are named with an
“-one” ending.
• The location of the carbonyl group in the
molecule is identified with the lowest
number possible.
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Ketones
H O H
H C
H
C
C H
H
2-propanone
(acetone or dimethyl ketone)
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Carboxylic Acid
• Carboxylic Acids are compounds in which the
carbonyl group is bonded to a carbon on one
side and a hydroxyl group on the other side.
• Named with an “-oic acid” ending.
• Carbonyl does not need to be numbered
since it is at the end.
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Carboxylic Acid
H O
H C
C O H
H
ethanoic acid
(acetic acid)
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Esters
• Esters contain a carbonyl group where the
carbonyl carbon is attached to a carbon on
one side an oxygen on the other; the oxygen
is then connected to another carbon.
• Similar to an ether, but has a carbonyl group
between the oxygen and a carbon.
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Esters
• Esters are named with an “-oate” ending.
• Again, the carbonyl group does not need to
be numbered since we name the group
found on each side of it.
• Many esters have pleasant odors.
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Esters
H O
H
H C
C O C
H
H
methyl ethanoate
(methyl acetate)
H
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Condensation Polymers
• Condensation Polymers – Polymers formed
by repeated condensation reactions of one
or more monomers.
• Condensation Reaction – Chemical
combination of two organic molecules,
accompanied by the loss of water or other
small molecule.
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Condensation Polymers
• One very common condensation polymer is
polyethylene terephthalate (PET). It has
many uses:
–Thin film for videotape
–The textile Dacron®
–More than 2 million kg are produced each
year in the U.S.
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