A process for treating an alkylation feedstock comprising olefins, n-alkanes, iso-alkanes, and impurities including one or more of butadiene, oxygenates, nitrogen-containing compounds, and sulfur-containing compounds, the process including: contacting an alkylation feedstock containing at least one of oxygenates and nitrogen-containing compounds with water to produce a hydrocarbon fraction having a reduced concentration of the at least one of oxygenates and nitrogen-containing compounds and an aqueous fraction comprising at least a portion of the at least one of oxygenates and nitrogen-containing compounds; separating water from the hydrocarbon fraction having a reduced concentration to produce a hydrocarbon fraction having a reduced water content; contacting the hydrocarbon fraction having a reduced water content with an oligomerization catalyst in a first oligomerization reaction zone under oligomerization conditions to react at least a portion of the olefins to form a reactor effluent comprising olefin oligomers; and feeding at least a portion of the reactor effluent to an alkylation unit.