A process for producing an alkylaromatic compound, the process comprising: (a) introducing a first feed comprising an alkylatable aromatic compound and a second feed comprising an alkene into a first alkylation reaction zone comprising a first alkylation catalyst, wherein the first alkylation catalyst has a first amount of acid sites per unit mass of the catalyst; (b) operating said first alkylation reaction zone under conditions effective to cause alkylation of said alkylatable aromatic compound by said alkene to produce said alkylaromatic compound, said conditions being such that said alkylatable aromatic compound is at least partly in the liquid phase; (c) withdrawing from said first alkylation reaction zone a first effluent comprising said alkylaromatic compound and unreacted alkylatable aromatic compound; (d) introducing at least part of said first effluent and a third feed comprising said alkene into a second alkylation reaction zone comprising a second alkylation catalyst, wherein the second alkylation catalyst has a second amount of acid sites per unit mass of the catalyst and wherein the first alkylation catalyst and the second alkylation catalyst comprise different zeolite materials and wherein said second amount is less than said first amount; (e) operating said second alkylation reaction zone under conditions effective to cause alkylation of said unreacted alkylatable aromatic compound by said alkene to produce said alkylaromatic compound, said conditions being such that said alkylatable aromatic compound is at least partly in the liquid phase; and (f) withdrawing from said second alkylation reaction zone a second effluent comprising said alkylaromatic compound. (a) introducing a first feed comprising an alkylatable aromatic compound and a second feed comprising an alkene into a first alkylation reaction zone comprising a first alkylation catalyst, wherein the first alkylation catalyst has a first amount of acid sites per unit mass of the catalyst; (b) operating said first alkylation reaction zone under conditions effective to cause alkylation of said alkylatable aromatic compound by said alkene to produce said alkylaromatic compound, said conditions being such that said alkylatable aromatic compound is at least partly in the liquid phase; (c) withdrawing from said first alkylation reaction zone a first effluent comprising said alkylaromatic compound and unreacted alkylatable aromatic compound; (d) introducing at least part of said first effluent and a third feed comprising said alkene into a second alkylation reaction zone comprising a second alkylation catalyst, wherein the second alkylation catalyst has a second amount of acid sites per unit mass of the catalyst and wherein the first alkylation catalyst and the second alkylation catalyst comprise different zeolite materials and wherein said second amount is less than said first amount; (e) operating said second alkylation reaction zone under conditions effective to cause alkylation of said unreacted alkylatable aromatic compound by said alkene to produce said alkylaromatic compound, said conditions being such that said alkylatable aromatic compound is at least partly in the liquid phase; and (f) withdrawing from said second alkylation reaction zone a second effluent comprising said alkylaromatic compound. <EOS>