BACKGROUND: The objective of this work was to improve the selective yield of cumene by transalkylating the (diisopropylbenzene) DIPB formed in benzene alkylation with propene and select the optimum process conditions for this transalkylation over SAPO-S catalyst. RESULTS: Higher benzene/DIPB mole ratios and higher space velocities were found to give better cumene selectivity. An apparent activation energy value of 130.2 kJ mol(-1) was obtained for the reaction with SAPO-5 as the catalyst. CONCLUSION: SAPO-5 shows promise when loaded with a small quantity of platinum (0.005% w/w) in the transalkylation of commercial DIPB (cumene column bottoms) with benzene. The kinetic investigations help in selecting optimum process operating conditions for maximizing the cumene yields in transalkylation of commercial DIPB over SAPO-5. (c) 2008 Society of Chemical Industry.