Hydrocarbons, C4, steam-cracker distillate; Petroleum gas; [A complex combination of hydrocarbons produced by the distillation of the products of a steam cracking process. It consists predominantly of hydrocarbons having a carbon number of C4, predominantly 1-butene and 2-butene, containing also butane and isobutene and boiling in the range of approximately minus 12 °C to 5 °C (10.4 °F to 41 °F).]