... ingredients are n-butane, isobutane, isobutene, 1,3-butadiene, 1-butene, 2-butene so. Mainly from the refining process and the production of ... butadiene and alkynes. Cracking cogeneration C4 paraffin content less, mainly butene and butadiene. Extractive Distillation of C4, also available absorption, zeolite ...