The present invention provides an improved process for the catalytic conversion of a feedstock comprising an alkylatable aromatic compound and an alkylating agent to form a conversion product comprising the desired alkylaromatic compound by contacting said feedstock in at least partial liquid phase under catalytic conversion conditions with a catalyst composition comprising a porous crystalline material having a structure type of FAU, BEA* or MWW, or a mixture thereof, wherein the porous crystalline material has a Relative Activity measured at 220° C. as an RA220 of at least 7.5 or measured at 180° C. as RA180 of at least 2.5, allowing operation at lower reaction pressures, e.g., a reaction pressure of about 450 psig (3102 kPa) or less, and lower alkylating agent feed supply pressure of 450 psig (3102 kPa) or less.