The olefin-containing fractions obtained in many petroleum refining and petrochemical enterprises consist of more than 50 wt. % low-molecular-weight C-2-C-4 olefins. A propylene-containing fraction produced in production of butadiene at the Tobol'sk Petrochemical Combine is such a fraction. The total concentration of ethylene and propylene in it is 65-90 wt. %. This fraction is a by-product and has no qualified use since separation of olefins from it in pure form requires large outlays, including capital expenditures.