Download Unit C Lesson 9 Elimination Substitution And Esterification Reactions

Elimination Reactions

In an elimination reaction, atoms are removed from an organic molecule and a
double bond is formed. This reaction is the reverse of an addition reaction.

A general elimination reaction:
Y
Z
C
C
C
C
+
Y
Z

Alcohols can be converted into alkenes when they are heated up in the presence of a
strong acid (H2SO4(aq)) catalyst.

EX. Propan-2-ol can be converted into propene. A water molecule is also produced.

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
H2SO4
butan-1-ol

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
H2SO4
butan-2-ol

Alkyl halides can be converted into alkenes when they are heated up in the presence
of a strong base, such as sodium ethoxide (NaOCH2CH3).

EX. Bromoethane can be converted into ethene by reacting with sodium ethoxide.
Ethanol and sodium bromide are also produced.

Isomers can also be produced by elimination reactions, if the double bond can form at
alternate locations.

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
2-bromobutane + sodium ethoxide

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
chlorocyclopentane + potassium hydroxide
Substitution Reactions

In a substitution reaction, a saturated hydrocarbon reacts with a halogen (X2). One
of the halogen atoms is substituted into the structure by taking the place of one of the
hydrogen atoms.

Isomers are often produced because there are different sites on the parent chain where
the halogen atom can be substituted in.

Substitution reactions have very slow reaction rates. They require the energy from
UV radiation to take place more quickly.

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
UV
propane + bromine

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
UV
benzene + iodine

EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
UV
iodobenzene + iodine
Esterification Reactions

An ester is produced by the reaction between an alcohol and a carboxylic acid. Water
is also produced.

These reactions require a strong acid (H2SO4) catalyst.

General esterification reaction:
O
O
H2SO4
R
C
OH
carboxylic acid

+
HO
R’
R
alcohol
C
ester
O
R’
+
HO
H
water
EX. Draw a structural diagram equation for the following reaction. Name all
possible products.
H2SO4
benzoic acid + ethanol

EX. What reaction forms pentyl propanoate, a fruity-smelling compound found in
apricots? Write out a word equation and a structural diagram equation.
Chem 30
Organic Reactions
For each of these organic reactions, complete the following:
 Draw a structural diagram equation
 Name all of the products following the first reaction step
 Identify the reaction type
1. propane + fluorine
UV
H2SO4
2. 2,2-dimethylpropanoic acid + methanol
3. 1,3,5-triethylbenzene + oxygen
4. 2-chloro-3-methylpentane + sodium ethoxide
5. 1-phenylcyclohexene + hydrogen chloride
6. cyclobutane + chlorine
UV
H2SO4
7. 2-methylpropan-1-ol + butanoic acid
8. 4-bromooct-1-yne + hydrogen
H2SO4
9. 3-methylcyclopentanol
10. 1,2-dichlorobenzene + bromine
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