Oligomerize for better gasoline

This paper reports on normal butene containing isobutene-depleted C{sub 4} hydrocarbons like raffinate II which are oligomerized using the Octol process in the liquid phase on a heterogeneous catalyst system to yield mainly C{sub 8} and C{sub 12} olefins. Raffinate II, the spent C{sub 4} fraction of an MTBE unit, is an ideal feedstock for further n-butene processing because of its high olefin concentration ranging between 70% and 80%. By modifications of MTBE technology, implementation of selective hydrogenation for removal of residual butadiene and superfractionating raffinate II, polymer grade 1-butene can be produced. Until the mid-70s raffinate I, the team cracker C{sub 4} cut after butadiene extraction, was mainly burned or blended into gasoline. Now nearly all raffinate I is or will be consumed for the purpose of converting isobutylene to MTBE.