Reactions of Organic
Compounds
Reactions of Organic Compounds
Chemical reactions of
organic compounds have
provided an abundance of
products we rely on.
However, the properties
that make them so useful
can also cause
environmental problems.
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The Plastika sailboat was built from
plastic bottles to raise awareness of
plastic pollution in ocean ecosystems.
Reactions of Organic Compounds
Types of Organic Reactions
Organic reactions can convert simple organic molecules
into large, complex ones.
TAXOL is an anti-cancer
drug that chemists can
synthesize.
Important types of organic reactions:
• addition
• elimination
• substitution
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• condensation
• esterification
• hydrolysis
• oxidation
• reduction
• combustion
Reactions Involving
Alkanes
Three types of chemical reactions
involving alkanes:
1. Halogenation (catalyzed by light)
i) CH4
+
Cl2
alkane
+
halogen
hv
ii) CH3CH3 + Br2
CH3Cl + HCl
halogenated alkane + acid
hv
A: Major and B: minor
product
Reactions of Organic Compounds
2. Substitution Reactions
•
•
•
Reaction in which a hydrogen or functional group has
been replaced by another functional group
Two compounds react to form two different compounds
The same number of atoms are bonded to the carbon
atoms of the reactants and products
Two compounds are
converted to two new
compounds.
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• -OH + CH3CH2Br
CH3CH2OH + Br -
Attacking
nucleophile
(hydroxide ion)
Examples of nucleophiles (shown in increasing reactivity):
CN- , I- , Br- , F- , Cl- , RO- , OH-
• CH3O- +
CH3CH2Br
Methoxide ion 1-bromoethane
• CH3O- + CH3CH2Br
Methoxide ion 1-bromoethane
CH3CH2OCH3 + Br ethyl methyl ether
• NaOH(aq) + CH3CH2Br
• Acetate ion + 1- bromo-1-cyclohexylmethane
3. Dehydrogenation (removal of H2)
-Formation of alkene from alkane
-Requires a platinum catalyst (Pt catalyst) and heat
(Δ)
Reactions of Organic Compounds
LEARNING CHECK
Draw and name the products of the
following substitution reaction.
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Answer on
the next slide
Reactions of Organic Compounds
LEARNING CHECK
The products formed are:
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REACTIONS INVOLVING
ALKENES AND ALKYNES
There are three main types of
reactions:
1. Addition Reactions
2. Hydrogenation Reactions
3. Polymerization Reactions
Reactions of Organic Compounds
1. Addition Reactions
• Reactions between an alkene or alkyne and a
small molecule (HOH, H2, HX, X2)
• Atoms of a small molecule are added to carbons
of a double or triple bond
• Reactions of alkynes can produce alkenes or
alkanes
• Constitutional isomers may form
Carbon atoms of the multiple
bond have more atoms bonded
to them in the product.
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UNIT 1 Chapter 2: Reactions of Organic Compounds
Section 2.1
Addition Reactions (cont’d)
One constitutional isomer will predominate.
To predict the major product:
Markovnikov’s rule:
The hydrogen atom of the small molecule will attach to
the carbon atom of the double bond that is bonded to
the most hydrogens.
The 2-chloropropane
isomer will be the
major product.
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Three types of Addition Reactions for
Alkenes and Alkynes
i) Hydration Reaction
H2SO4
CH3CH2CH=CH2 + HOH
catalyst
CH3CH2-CH-CH2
OH H
MAJOR PRODUCT:
THE RICH GET RICHER
Major :“Rich get
richer”
OH
CH3CH2C
CH
HgSO4, H2SO4
H 2O
CH3CH2C=CH2
an enol
Oxidation
rxn
O
CH3CH2CCH3
a k etone
Addition Reactions
ii) Hydrohalogenation Reaction
H
CH3CH=CHCH2CH3 + HCl
CH3CH-CHCH2CH3
Cl
-two carbon atoms left of
anion….two carbons right of
anion……symmetrical molecule is
more stable (major product)
Addition of hydrogen halides:
H
H X
|
|
|
— C  C— + HX → — C = C — + HX → — C — C —
|
|
|
X
H
X
a) HX = HI, HBr, HCl
b) Markovnikov orientation (second hydrogen adds to the
carbon with the most hydrogens)
Cl
CH3CCH + HCl → CH3C=CH2 + HCl → CH3CCH3
Cl
Cl
Br
CH3CH2C
CH
HBr
CH3CH2C
HBr
CH2
Br
CH3CH2CCH3
Br
General:
X = halogen
Addition Reactions
iii) Halogenation Reaction
Addition of X2
X
X X
|
|
|
— C  C— + X2 → — C = C — + X2 → — C — C —
|
|
|
X
X X
CH3CCH + Br2
Br
Br Br
→ CH3C=CH + Br2 → CH3-C-CH
Br
Br Br
Br
C CH
Br 2
H
C
C
Br
Br 2
Br Br
C
C H
Br Br
UNIT 1 Chapter 2: Reactions of Organic Compounds
Section 2.1
LEARNING CHECK
Show major and minor products that
can form from the following reaction.
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Answer on
the next slide
UNIT 1 Chapter 2: Reactions of Organic Compounds
LE A R N I N G
CH E C K
The chlorine atoms can be added to
either carbon 2 or 3 in this addition
reaction.
MAJOR
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Section 2.1
Reactions of Alkenes and Alkynes
2) Hydrogenation Reaction
- also known as reduction reaction
- opposite of dehydrogenation
- H2 is added along the double bond
- requires platinum catalyst (Pt) and heat (Δ)
Addition of H2
— C  C — + 2 H2, Ni →
(excess)
H H
|
|
—C—C—
|
|
H H
alkane
requires catalyst (Ni, Pt or Pd) and heat
Under normal
conditions, the
trans isomer
would be the
major
Excess
3) Polymerization
- a large polymer with repeating
structural units (monomers)
- more in chapter 2…..
Homework
page 27# 1-3
page 31#2(a-d), 3(a-c)