Organic Chemistry

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Organic Chemistry
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Alkynes
-Contain carbon-carbon triple bonds -sp-Hybridizat
ion -Unsaturated hydrocarbons -CnH2n-2
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IUPAC names
-Alkynes name are similar to that for alkanes.
..ane ..yne
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Physical Properties of Alkynes

• C2-C4 GAS
• C5-C17 LIQUID
• ? C18 SOLID

mp. bp. 2. Ethyne C2H2 80.8 -84.0
Propyne C3H4 101.5 -23.2 Butyne
C4H6 125.7 8.1
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Why ???
Why ???
bp Cis-isomer ? trans-isomer
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Isomers

• Same formula
• Different structure
• Different molecule with different properties
  must have a different name!

Isomers of C4H6
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Isomers of C5H8
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Reaction of Alkyne
1. Combustion reaction
2. Addition reaction -Hydrogenation reaction
(H2) Ni, Pd, Pt cat. -Halogenation reaction
(X2 / CCl4 )
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-Hydrohalogenation reaction (HBr)
-Hydration reaction (H2O)
Condition.
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3. Oxidation reaction
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Aromatic Compound

• The structure must be cyclic, containing some
  number of conjugated pi bond.
• HUCKEL s rule (4n2 n0,1, 2,3,4)
• aromatic system 2, 6, 10, 14)