Distillates (petroleum), C 3-5 , 2- methyl-2-butene-rich; Low boiling point naphtha — unspecified (A complex combination of hydrocarbons from the distillation of hydrocarbons usually ranging in carbon numbers from C 3 through C 5 , predominantly isopentane and 3-methyl-1-butene. It consists of saturated and unsaturated hydrocarbons having carbon numbers in the range of C 3 through C 5 , predominantly 2-methyl-2-butene.)