Abstract: A new synthetic technique for preparing long-chain alkylated naphthalenes was developed using naphthalene and long-chain linear alpha-olefins as raw materials and heteropoly acid (silica-supported 12-phosphotungstic acid) as catalyst. The influences of various olefins and reaction conditions on the product yield and properties were studied. It was found that under the optimum reaction conditions of using cetene as alkylation agent, a catalyst dosage of 4%, a cetene to naphthalene molar ratio of 1.35, a reaction temperature of 130 ℃ and a reaction time of 50 min, the product yield was 88.2%. The obtained product had a viscosity index of 104, a pour point of -27℃ and with good oxidation stability, its oxidation decomposition temperature by DSC（O2）test was 225.3℃.

Key words: Naphthalene, Olefins, Alkylation, Reaction conditions, viscosity index