My presentation about PROPYNE

1. Propyne
By Lê Hà Minh Châu,Tô Phạm
Quỳnh Mai
I. Introduction
II. Physical properties
III.Chemical properties
IV. Preparation
V. Applications

2. Introduction

3. Introduction
• Chemical formula: C3H4
• Structure:
• Name:
+ IUPAC name: Prop-1-yne
+ Common names: Propyne,
Methylacetylene.

4. Physical
properties

5. Physical properties
Title Properties
Molar mass 40.0639 g/mol
Appearance Colorless gas
Odor Sweet
Density 0.53 g/cm3
Melting point −102.7 °C (170.5 K)
Boiling point −23.2 °C (250.0 K)

6. Chemical
properties

7. 1. Addition reaction
• A triple bond adition reaction can
take place in two stages
• Markovnikov’s law: The rich get
richer.
• Similar to addition reaction of
alkenes
• 1 pi bond becomes 2 sigma bonds.
• Usually exothermic

8. a) Halogenation (X2)
• Cl2 and Br2 add to alkynes to form
vinyl dihalides.
• May add syn or anti, so product is
mixture of cis and trans isomers.
• Difficult to stop the reaction at
dihalide.

9. b) Hydrohalogenation (HX)
•Markovnikov’s law:H atoms of hydrogen
halides into atoms C
double bind more H atoms.
•HCl, HBr, and HI add to alkynes to form
vinyl halides.
•If two moles of HX is added, product is a
geminal dihalide.

10. c) Hydrogenation (H2)

11. d) Hydration (H2O)
• Mercuric sulfate in aqueous sulfuric
acid adds H-OH to one pi bond with a
Markovnikov orientation, forming a
vinyl alcohol (enol) that rearranges to
a ketone.
• Hydroboration-oxidation adds H-OH
with an anti-Markovnikov orientation,
and rearranges to an aldehyde.

12. 3. Substitution reaction
• Substitution on the alkyne reaction involves the
release of H atoms bound to the C C bond at the
end of the chain of alkyne
CH≡C-CH3 + AgNO3/NH3 → Ag-C≡-C-CH3↓ + NH4NO3
silver asetilide

13. 4. Oxidation reaction
a, KMnO4
• Dilute, neutral solution of KMnO4
• Oxidizes alkynes to a diketone.
• Warm, basic KMnO4 cleaves the
triple bond.
• Ozonolysis, followed by hydrolysis
cleaves the triple bond.

14. 4. Oxidation reaction
b, Combustion reaction
• Combustion propyne with a limited amount
of O2, CO or C will result in:
C3H4(g) + 4O2(g) 3CO2(g) + 2H2O(g)

15. Preparation

16. Preparation
• The separation reaction of dihalogen in
the solution of base and alcol
• Two times dehydrogenation of propane

17. Applications

18. Applications
a, Use as a rocket fuel
• Less toxic
• Advantageous for craft intended
for low Earth orbital operations
b, Organic chemistry
• Organic synthesis
• Used to synthesize vitamin E

19. Thank you
for listening!