Alkynes Reactions and Catalysts

Complete Hydrogenation

• Alkyne → alkane

• Xs H2 with Raney Nickel at 180

Partial Hydrogenation

• Lindlar’s Catalyst which is Poisoned Palladium and Heat

Halogenation

X2 in CCl4

Hydrohalogenation

• HX

Hydrohalogenation

• HgCl2 at 150 +HCl

Hydration

• HgSO4 +H2SO4 + h20

• 60

• FORMS TAUTOMER!!

Acidity of Terminal Alkynes

• AgNo3 or CuCl

• Ag is white

• Cu is red

No3/Cl will react with displaced H

Trimerization of Ethyne

• absence of oxygen, heat and pressure

• forms benzene

Dehydrohalogenation

• heat under reflux, alcoholic KOH

• need a dihalide

• NEVER TAKE HALOGEN AND H FROM SAME CARBON

Converting Carbon to Ethyne

• CaC2 +H20 → ethyne and Ca(OH2)