Chemical Name: Propyne
IUPAC NAME: Prop-1-yne
CAS No.: 74-99-7
EINECS: 200-828-4
RTECS: UK4250000
Molecular Formula: C₃H₄
Molecular Weight: 40.06 g/mol
Melting Point: −102.7 °C(lit.)
Density: 0.648 g/cm3
Following is the structure of MEthyl acetylene (74-99-7):

Product Categories about MEthyl acetylene (74-99-7) are Allyl Monomers ; Monomers ; Polymer Science ; Chemical Synthesis ; Compressed and Liquefied Gases ; Synthetic Reagents
The chemical synonymous of MEthyl acetylene (74-99-7) are Methylacetylene ; 1-Propyne ; Allylene ; Propyne ; Acetylene, methyl- ; Ch3cequivch ; Methyl-acetylen ; Propine

Reported in EPA TSCA Inventory.

This compound is a simple anesthetic and in high concentration is an asphyxiant. Mutation data reported. Dangerous fire hazard when exposed to heat or flame; can react vigorously with oxidizing materials. Explosive in the form of vapor when exposed to heat or flame. Localized heating of liquid-containing cylinders to 95°C may cause an explosion. Product of reaction with silver nitrate ignites at 150°C. A commercial mixture containing 30% propyne in MAPP gas is similar to ethylene in potential hazards and handling requirements. To fight fire, stop flow of gas. When heated to decomposition it emits acrid smoke and irritating fumes. See also ACETYLENE COMPOUNDS and ALKYNES.
Hazard Codes:
Xi: Irritant
F: Flammable
Risk Statements about MEthyl acetylene (74-99-7):
R11 Highly flammable.
R37 Irritating to respiratory system.
Safety Statements about MEthyl acetylene (74-99-7):
S16 Keep away from sources of ignition.
S36 Wear suitable protective clothing.
S38 In case of insufficient ventilation, wear suitable respiratory equipment. 
 

OSHA PEL: TWA 1000 ppm
ACGIH TLV: TWA 1000 ppm
DFG MAK: 1000 ppm (1700 mg/m³)

 MEthyl acetylene (74-99-7) is a convenient three-carbon building block for organic synthesis. Deprotonation with n-butyllithium gives propynyllithium. This nucleophilic reagent adds to carbonyl groups, producing alcohols and esters.Whereas purified propyne is expensive, MAPP gas can be used to cheaply generate large amounts of the reagent.It exists in equilibrium with allene, the mixture of methylacetylene and propadiene being called MAPD.Research by European space concerns into using light hydrocarbons with liquid oxygen as a relatively high performing propellant combination which would also be less toxic than the commonly used MMH/NTO (monomethylhydrazine/nitrogen tetroxide) systems, showed that propyne would be highly advantageous as a rocket fuel for craft intended for low Earth orbital operations. This conclusion was reached based upon a specific impulse expected to reach 370 s if oxygen is used as oxidizer, a high density, and energy/volume ratio, and the moderate boiling point, which causes the chemical to present fewer problems in storage than for example a fuel that needs to be kept at extremely low temperatures.