Cumene is produced by alkylation of benzene with propylene in the presence of a
solid phosphoric acid (SPA) catalyst that is a composite of phosphoric acid and a
binder such as kieselguhr or diatomaceous earth (Prinsloo, 2007). The following
reactions occur in a fixed bed of catalyst pellets at the temperature of 350C and
pressures ranging from 25 to 32 bar in the vapor phase.