Alkynes are unsaturated hydrocarbons containing a carbon-carbon triple bond. They have the general formula CnH2n-2. The IUPAC system names alkynes by adding the suffix -yne, which indicates the presence of a triple bond. Higher alkynes are named by numbering the longest carbon chain containing the triple bond from the end that gives the lower set of numbers to the triply bonded carbons.

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Alkynes
March 4, 2014

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Objectives:
1. Define alkynes
2. Name alkynes using
the IUPAC system
of nomenclature

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What is an
alkyne?

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Alkyne
An unsaturated
hydrocarbon that
contains a carbon –
carbon triple bond

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Alkyne
General Formula:
CnH2n-2

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Naming Alkynes
The key to the IUPAC name
of an alkyne is the ending
–yne, which shows the
presence of a carbon-carbon
triple bond.

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Examples
HC CH
Ethyne
CH3C CH
Propyne

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Naming Alkynes
1. In higher alkynes, number the
longest carbon chain that contains
the triple bond from the end that
gives the lower set of numbers to
the triply bonded carbons. Indicate
the location of the triple bond by
the number of its first carbon atom.

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Naming Alkynes
2. Naming branched alkynes
is the same with those of
alkenes. The same rules
apply.

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Examples

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Examples

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QUIZ – ¼ sheet
Name the following:
1.

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2.

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3.

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4.

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5.

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Assignment
Give the importance of
alkynes.

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