Application of solid acid catalysts in naphthalene alkylation reaction

Alkyl naphthalene is a synthetic lubricant known for its excellent lubricating properties, including high thermal stability, good viscosity, and oxidation resistance. In this research, the performance of several solid acid catalysts, such as Y zeolite, ZSM-5, MCM-22 and AlMCM-41, was investigated in the alkylation reaction of naphthalene with tetradecene. The catalytic materials were characterized by ICP, BET, N₂ adsorption–desorption isotherms and Py-IR. The experimental findings revealed that Y zeolites showed great potential for the preparation of monoalkyl naphthalene. Notably, Na⁺ ions exhibit a poisoning effect on the acidity of zeolites, particularly in Y zeolites. To investigate this issue, Y zeolites with different Na contents were prepared by an ion exchange method, followed by evaluation and characterization. The results indicated that the catalytic activity of Y zeolites with high Na content was poor. With the decrease of Na content, the catalytic performance of the catalyst was obviously improved, but the selectivity for monoalkyl naphthalene gradually decreased.