Propylene (or propene) is an alkene (a hydrocarbon containing a carbon-carbon double bond) a colorless gas with a faint petroleum like odor. It is shipped as a liquefied gas under its own vapor pressure. For transportation it may be stenched. Contact with the liquid can cause frostbite. It is easily ignited. The vapors are heavier than air. Any leak can either be liquid or vapor. It can asphyxiate by the displacement of air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used to make other chemicals. Can cause explosion.
Uses on Mars
Propylene, like many alkenes, are highly desirable as intermediates for petrochemical production. This is a necessary chemical for chemical production on Mars (In-situ resource utilization). Two important uses are in the production of polypropylene (via polymerization) and butanol (via hydroformylation).