(442c) A Comparative Study On Selective Alkylation of Naphthalene Catalyzed by Various Lewis Acidic Ionic Liquids

A series of double long-chain alkylnaphthalene were synthesized from naphthalene and long-chain α-alkenes catalyzed by various Lewis acidic ionic liquids in this paper. The Lewis acidic ionic liquids could be luckily used as catalyst instead of traditional acidic catalysts even zeolites in the process of alkylation with high activity because traditional acidic catalysts have several disadvantages, such as corrosion, low selectivity, and environmental pollution since difficultly recoved. More than that, the alkylated products and unreacted reactants could be isolated easily by decantation from the immiscible ionic liquid phase. In this paper, various Lewis acidic ionic liquids composed of AlCl₃-Et₃NHCl, ZnCl₂-Et₃NHCl or FeCl₃-Et₃NHCl were tested and the influences of type and dosage of catalyst, cationic-anionic proportion of ionic liquids, molar ratio of naphthalene to alkenes, reaction temperature, and reaction time were investigated. Excellent conversion of reactants and different selectivity of the alkylated product were achieved, and finally the catalyst could be recycled for several times without any obvious loss of its catalytic activity.