Naphthalene was alkylated with propylene to isopropylnaphthalene (IPN) and diisopropylnaphthalenes (DIPN) and isopropylnaphthalene was converted (disproportionation, isomerization) in the liquid phase over various aluminosilicate catalysts, i.e. H-mordenite, HY zeolite and amorphous aluminosilicate. The reactions were studied in relation to temperature over the range of 150-300 degrees C. The mono-and di-alkylation were less beta-selective over H-mordenite (HM) than over HY zeolite or over amorphous aluminosilicate. Nevertheless, in the alkylation product obtained over HM the 2,6-DIPN/2,7-DIPN ratio was as high as 1.6-1.8, indicating shape-selectivity. In the IPN conversion test the 2,6-DIPN/2,7-DIPN ratio was initially close to 1 but then rose to almost 1.5, indicating that TPN can be disproportionated to yield naphthalene and DIPN over the HM zeolite both on external surface and inside the pores.