Abstract: A method of cycloalkylating naphthalene with at least one cyclic group, characterized by the following points:a) as catalyst, there is used a zeolite of faujasite structure having pore openings greater than 6.7 .ANG., the silica/alumina ratio of this zeolite being greater than 2.5 and its residual content of alkaline ion(s) being less than 3%;b) the reaction is carried out batchwise in heterogenous liquid/solid phase at a temperature of between 20.degree. C. and 250.degree. C., under a pressure at most equal to 30 bars. Cycloalkylated naphthalenes are obtained by this method, in particular 2,6-dicyclohexyl naphthalene.

Abstract: A method of preparing an alkylated aromatic product (12) by alkylation of an aromatic compound (1), the alkylation producing several alkylated aromatic products, this method being characterized by the following points:(a) the aromatic compound (1) is reacted with an alkylating agent (2) in the presence of an alkylation zeolite (4);(b) the alkylated aromatic product (12) is separated by crystallization from the products of the alkylation;(c) the uncrystallized part (13) of the alkylated aromatic products is subjected to a dealkylation in the presence of a dealkylation zeolite (15);(d) the regenerated aromatic compound (1.sub.b) is recycled in order to react it again with the alkylating agent (2) in the presence of the alkylation zeolite (4). Alkylated aromatic compounds (12) obtained by this method, in particular 2-6 dicyclohexyl naphthalene.