Abstract: A process for selectively producing 1-butene comprises contacting at least one antifouling agent with at least one aluminum alkyl compound to form at least one antifouling compound in a first step. The antifouling compound may comprise a structure comprising a central aluminum molecule bound to an R1 group, bound to an R2 group, and bound to an R3 group. The process further comprises feeding the antifouling compound, an additional amount of the aluminum alkyl compound, at least one titanate compound, and ethylene into a reactor to dimerize ethylene in a second step. The titanate compound is fed as a stream separated from the streams of the antifouling compound and the additional amount of the aluminum alkyl compound. The molar ratio of the sum of the aluminum alkyl compound to the titanate compound is equal to or higher than 1.5 and equal to or lower than 3.