ABSTRACT The heterogeneously catalyzed co‐oligomerization of ethylene, propylene, and iso‐butylene was studied focusing on the production of gasoline and kerosene. Silica‐alumina catalysts were employed with and without nickel loading. Initially, the homo‐oligomerization of iso‐butylene was studied employing a series of catalysts and varying reaction conditions. Due to the high reactivity of iso‐butylene, conversion was almost quantitative and selectivities to kerosene reached 96% while selectivities to gasoline reached 83%. Subsequently, co‐oligomerization of iso‐butylene with ethylene and propylene was investigated. Employing nickel‐loaded silica‐alumina catalysts, all olefin species can be converted, despite the very different reactivity. Selectivities to kerosene and gasoline were up to 92% and 83%, respectively. It is shown that iso‐butylene can be easily separated from such olefin mixtures by oligomerization, due to its much higher reactivity compared to propylene and ethylene. A long‐term run lasting for 196 h showed continuous deactivation of the catalyst regarding the conversion of ethylene and propylene, whereas conversion of iso‐butylene remained close to 100%. As a result, conversion of iso‐butylene dominates and molecular branching increases, as indicated by the isoindex. It is shown that the catalyst can be easily reactivated by heating and catalytic performance can be fully restored.
Fuchs et al. (Thu,) studied this question.