a colorless, flammable gas, C4H6, soluble in alcohol but not in water, usually derived from butane or butene: used chiefly in the manufacture of rubber and paint, and in organic synthesis.
butadiene (by'tə-dī'ēn') Pronunciation Key
A colorless, highly flammable hydrocarbon obtained from petroleum and used to make synthetic rubber. Chemical formula:C4H6.
[vahyn-l-eth-uh-leen] 
'tə-dī'ēn') Pronunciation Key
lˈɛθ