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Section 11.2—Organic
functional groups
How do other elements change the properties of the molecules?
Functional group
Functional Group – Group of atoms on
the carbon backbone that have
“functions” (they change the properties
of the molecule).
IUPAC
IUPAC – International Union of Pure
and Applied Chemistry. Develops rules
about how to systematically name
organic molecules to indicate all the
functional groups and their positions.
Haloalkanes
Halolkanes – Hydrocarbons with one or
more halogens (F, Cl, Br or I)
Properties of Haloalkanes
Polar molecules (unlike hydrocarbons)
Able to form dipole-dipole intermolecular
forces
Generally are more soluble in water than
hydrocarbon of the same size
Have higher melting and boiling points
than hydrocarbon of the same size
Naming Haloalkanes
Name it the same as alkanes (count
longest chain of carbons and use it to
choose organic prefix).
Count which carbon the halogen is on so
that the number is as low as possible
Put the carbon number and the halogen
prefix (fluoro-, chloro-, bromo- or iodo-)
before the alkane name
Example #1
Example:
Name the following
molecule
Example #1
Example:
Name the following
molecule
Find the longest chain of carbon atoms
A chain of 4 carbons = butAll single bonds = -ane
4
Example #1
Example:
Name the following
molecule
3rd carbon
2nd carbon
Find the longest chain of carbon atoms
4
A chain of 4 carbons = butAll single bonds = -ane
2-bromobutane
“bromo-” is on the 2nd carbon (choose smallest possible number)
Alcohols
Alcohol – Contains a “-OH” group
Properties of Alcohols
Polar molecules that can hydrogen bond
Are more soluble in water than
hydrocarbons of same size
Have higher melting and boiling points
than hydrocarbons of same size
Alcohols are toxic (even beverage alcohol,
ethanol)
Naming Alcohols
Count the longest chain of carbon atoms
and choose the appropriate prefix
Count which carbon the “-OH” is on—
count from the end CLOSEST to the -OH.
Put this number in front of the prefix
Use the suffix “-ol”
Example #2
Example:
Draw the structure
for 1-propanol
Example #2
Example:
Draw the structure
for 1-propanol
“prop-” = 3 carbons
“-ol” = “-OH” group
“1” = “-OH” group is on first carbon atom
Let’s Practice #1
Name the following
molecule
Let’s Practice #1
Name the following
molecule
Find the longest chain of carbon atoms
A chain of 4 carbons = but-
4
Let’s Practice #1
Name the following
molecule
3rd carbon
2nd carbon
Find the longest chain of carbon atoms
A chain of 4 carbons = but“-OH” group = “-ol”
2-butanol
OH is on second carbon
Ethers
Ether – Contain an “O” between two “C”
atoms
Properties of Ethers
It does contain an oxygen, like alcohols
But oxygen is in-between 2 carbon atoms
Therefore they have lower intermolecular forces
than alcohols
Only the two smallest ethers are soluble in
water
They have lower melting and boiling points
than alcohols of the same size
Naming Ethers
Count the carbon atoms on one side of the
oxygen and choose the appropriate prefix
Count the carbon atoms on the other side
and use the appropriate prefix
If they are the same, use “di_____ ether”
with the prefix
If they are different, write the lower
number prefix, then the higher number,
then “ether”
Example #3
Example:
Name the following
molecule
Example #3
“ether”
Example:
Name the following
molecule
Carbons on one side
1 = “methyl”
Carbons on other side
1 = “methyl”
Prefixes are the same
“dimethyl”
Dimethyl ether
Let’s Practice #2
Draw a molecule of
methyl ethyl ether
Let’s Practice #2
Draw a molecule of
methyl ethyl ether
“methyl” = 1 carbon on one side
“ethyl” = 2 carbons on the other side
“Ether” = oxygen in between the two sides
Amines
Amine – A nitrogen with saturated
carbons attached
Properties of Amines
 It can hydrogen bond, but less strongly than
alcohols (and –OH group)
 Generally less soluble in water than alcohols of
the same size
 Generally lower melting and boiling points than
alcohols of the same size
 Some have unpleasant smells (decaying organic
material, etc.)
 They can act as a Lewis base (electron donors)
Naming Ethers
They are named the same way as ethers,
but with “amine” at the end
Count carbons on each side and use the
prefixes
Example #4
Example:
Name the following
molecule
Example #4
Example:
Name the following
molecule
Carbons on one side
1 = “methyl”
Carbons on other side
2 = “ethyl”
Methyl ethyl amine
Carbonyl
Carbonyl – A carbon atom double
bonded to an oxygen atom. It’s a polar
functional group
There are several types of compounds that have carbonyls:
Carboxylic acid
Aldehyde
Ketone
Anhydride
Carboxylic Acid
Carboxylic acid – Contains a carbonyl
with an –OH group
“carbonyl”
“-OH” group
Naming Carboxylic Acids
Count the carbons (including the carbon in
the carbonyl) and choose the prefix
Include “-ic acid”
Example #5
Example:
Name the following
molecule
Example #5
carboxylic
acid
Example:
Name the following
molecule
4 carbons = butCarboxylic acid = -ic acid
Butyric acid
Aldehyde
Aldehyde – Contains a carbonyl with a
hydrogen atom on the carbonyl carbon
“carbonyl”
Hydrogen atom
Naming aldehydes
Count the carbons (including the carbon in
the carbonyl) and choose the prefix
Include “-al”
Example #6
Example:
Draw methanal
Example #6
Example:
Draw methanal
Meth- = 1 carbon
-al = carbonyl with hydrogen
Ketone
Ketone – Contains a carbonyl with 2
carbon atoms bonded to the carbonyl
Naming ketones
Count the carbon atoms on either side of
the carbonyl and choose the two prefixes
Do not count the carbonyl
Include “ketone”
Example #7
Example:
Name the following
molecule
Example #7
“carbonyl”
Example:
Name the following
molecule
1 carbon = methyl
2 carbons = ethyl
Carbonyl between two carbons = ketone
methyl ethyl ketone
Anhydride
Anhydride – Contains a carbonyloxygen-carbonyl group
Naming anhydrides
If they are symmetrical:
Count the carbon atoms (including the carbonyl
carbon) on one side. Choose the prefix.
Use “-ic anhydride”
If it’s not symmetrical:
Count each carbon chain (including the
carbonyl carbon atoms). Choose prefixes
Use both prefixes with “-ic anhydride”
Example #8
Example:
Name the following
molecule
Example #7
anhydride
Example:
Name the following
molecule
Symmetrical with 2 carbon chains = eth-
Ethanoic anhydride
Aromatic Compounds
Aromatic Compounds –
ring of six carbon atoms with
alternating single and double
bonds.
Phenol – aromatic ring with
“–OH” group
Aromatic Compounds
“Aromatic” because most of them have
odors
Carcinogens
Cancer-causing compounds
Aromatic rings can be connected together
or have functional groups