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Timberlake LecturePLUS 1999 1
Chapter 11Haloalkanes, Alkenes, and Alkynes
Functional Groups
Haloalkanes
Timberlake LecturePLUS 1999 2
Functional Groups
Part of an organic molecule where chemical reactions take place
Composed of an atom or group of atoms Replace a H in the corresponding alkane Provide a way to classify organic
compounds
Timberlake LecturePLUS 1999 3
Some Types of Functional Groups
Haloalkane -F, -Cl, -Br CH3Cl
Alcohol -OH CH3OH
Ether -O- CH3-O-CH3
Aldehyde
KetoneC
O
CH3CH
O
C H
O
CH3CCH3
O
Timberlake LecturePLUS 1999 4
More Functional Groups
Carboxylic acid -COOH CH3COOH
Ester -COO- CH3COOCH3
Amine -NH2 CH3NH2
Amide -CONH2 CH3CONH2
Timberlake LecturePLUS 1999 5
Haloalkanes
An alkane in which one or more H atoms is replaced with a halogen (F, Cl, Br, or I)
CH3Br 1-bromomethane
Br (methyl bromide)
CH3CH2CHCH3 2-bromobutane
Cl
chlorocyclobutane
Timberlake LecturePLUS 1999 6
Learning Check HA1
Name the following:
Br
Cl
Cl
Timberlake LecturePLUS 1999 7
Solution HA1
Name the following:
bromocyclopentane
1,3-dichlorocyclohexane
Br
Cl
Cl
Timberlake LecturePLUS 1999 8
Substituents
List other attached atoms or group in alphabetical order
Br = bromo, Cl = chloro
Cl Br
CH3CHCH2CHCH2CH2CH3
4-bromo-2-chloroheptane
Timberlake LecturePLUS 1999 9
Learning Check HA2
The name of this compound is:
Cl CH3
CH3CH2CHCH2CHCH3
1) 2,4-dimethylhexane
2) 3-chloro-5-methylhexane
3) 4-chloro-2-methylhexane
Timberlake LecturePLUS 1999 10
Solution HA2
The name of this compound is:
Cl CH3
CH3CH2CHCH2CHCH3
3) 4-chloro-2-methylhexane
Timberlake LecturePLUS 1999 11
Haloalkanes as Anesthetics
Halothane (Fluothane) F Cl
F C C Br
F HFluothane is a haloalkane that is widely used as an anesthetic, which is a compound that decreases the ability of the nerve cells to conduct pain.
Timberlake LecturePLUS 1999 12
Ozone Layer
Ozone layer
Stratosphere
(10-30 miles
Above Earth)
Timberlake LecturePLUS 1999 13
Chlorofuorocarbons (CFCs and the Ozone Layer
ozone O3 layer absorbs most of the sun’s harmful radiation.
CFCs - chlorofluorocarbons - are depleting that ozone layer.
CFCs are used as Freons in refrigeration,
air conditioning, and foam insulation.
Their use in spray cans is no longer allowed.
Timberlake LecturePLUS 1999 14
Chlorofuorocarbons and the Ozone Layer
In the stratosphere, the CFCs react with
the high-energy UV radiation from the sun
UV light
CF2Cl2 CF2Cl + Cl
Freon-12 free radical
Timberlake LecturePLUS 1999 15
Chlorofuorocarbons and the Ozone Layer
To become stable, the Cl acquires an electron from ozone O3 and produces ClO.
Cl + O3 ClO + O2
The presence of ClO in the atmosphere is an indicator of the disappearance of ozone.
Timberlake LecturePLUS 1999 16
Impact of Loss of Ozone Layer
According to the National Academy of
Sciences, each 1% loss of ozone increases
by 2% the amount of UV radiation reaching
the earth. More UV radiation means more
skin cancer and cataracts in humans, more
intense photochemical smog, and lower crop
yields.