Acidic zeolite catalysts like mordenite have been used in the alkylation of benzene. Alkylation of benzene has been carried out with 1 - dodecene over a range of as - synthesized acidic mordenites having varying particle size distribution in the nanometer range. Selectivity towards the 2 - phenyl dodecane is of prime importance as it leads to the preparation of linear alkyl benzene sulfonates having better biodegradability compared to the other isomers. Metal cation exchanged acidic mordenites showed better selectivity towards the 2 - phenyl isomer under similar reaction conditions. These as - synthesized acidic mordenites were found to be comparable to the performance of commercial mordenite. Unlike conventional methods, where HF, HNO3, or other mineral acids are used for generating acidic properties in mordenites or for their dealumination, no acids have been used in the entire process of either the synthesis of catalyst or for the reaction.