Alkylation reactions of benzene with propylene using heterogeneous catalysts H+-beta zeolite, MCM-22, and ZSM-5 were studied for their affinity for cumene production. This work focused on the gas-phase reaction using different crystalline catalysts at several temperatures and amounts of reactants using both batch and continuous fixed-bed reactors. The properties of baseline commercial H+-beta catalysts versus versions modified with Ga, La, and Pt were studied. Quantitative analysis of product mixture was performed by gas chromatography. For the batch reactor, beta-zeolite produced the highest cumene yield and selectivity of 72% and 92%, respectively, at 225 degrees C. At this temperature, a benzene:propylene dilution of 7:1 molar ratio was the optimum. For the continuous system, cumene production is favored at lower space velocities, higher benzene-to-propylene ratio, and temperatures close to 225 degrees C. Ga modification of the H+-beta zeolite significantly enhanced cumene yield in the continuous fixed-bed reactor at 225 degrees C, from 27% of the unmodified beta-zeolite to 36% for the Ga-modified one. The life span of modified beta-catalysts was studied in the fixed-bed reactor for the first eight hours of reaction.