Hydrogenation of naphthalene with platinum—aluminium borate catalysts

Naphthalene dissolved in n-hexadecane was used as a model compound to simulate the aromatics in diesel fuels for hydrogenation activity tests. The aluminium borate (ABx) supports were prepared by the coprecipitation method. The aromatic hydrogenation activity of Pt/aluminium borate catalyst (Pt—ABx) is higher than that of Pt—γ-Al₂O₃ catalyst, but its cis-decalin selectivity is lower than that of Pt—γ-Al₂O₃ catalyst owing to the higher acidity of ABx than γ-Al₂O₃ support. When the Al:B atomic ratio decreases, the hydrogenation and hydrogenolysis activities of Pt—ABx catalyst increase but the cis-decalin selectivity decreases.

When boron is added to the Pt—γ-Al₂O₃ catalyst to give Pt—Bx—Al₂O₃ catalyst, it improves the catalyst hydrogenation activity but reduces the cis-decalin selectivity since the acidity of the support increases. However, the hydrogenation activity of Pt—Bx—Al₂O₃ catalyst deceases when the Al:B ratio is smaller than 8. The Pt—Bx—Al₂O₃ is a better aromatic hydrogenation catalyst than Pt—AB_x catalyst since its hydrogenolysis activity is lower.