Abstract: Improved acid catalyzed alkylation reactions occur for the addition of a hydrocarbyl reactant to an alkene, by the optimized addition of an oxidizing agent, such as a peroxide, molecular oxygen, ozone, peracid, and one or more of the peroxide, molecular oxygen, ozone, or peracid mixed with at least one material selected from the group consisting of the hydrocarbyl reactant, and the alkene. The hydrocarbyl species contains at least one tertiary carbon atom attached to hydrogen, such as isobutane. The alkene is preferably 1- or 2-butene. Suitable peroxides are found in the group consisting of: tert-butyl peroxyneopentanoate ((CH.sub.3).sub.3 C--O--OCO--C(CH.sub.3).sub.3); acetyl peroxide (CH.sub.3 CO--O--O--COCH.sub.3); di-tert-butyl peroxide ((CH.sub.3).sub.3 C--O--O--C(CH.sub.3).sub.3); hydrogen peroxide (H.sub.2 O.sub.2) and peracids of carboxylic acid having up to 10 carbon atoms, and a general chemical formula C.sub.n H.sub.2n O.sub.3, where n has values in the range 2-10.