Understanding the catalytic behavior of ionic liquids in tetralin alkylation with α-olefins through experiment and COSMO-RS model

[Display omitted] •A series of alkyltetralin similar to naphthenic base oils obtained by alkylation of tetralin and various α-olefins accessible from coal chemical industry.•Ionic liquids can be selected as excellent catalyst for tetralin alkylation with α-olefins.•COSMO-RS model to predict the mutual solubility and interaction of tetralin, olefins and alkyltetralins in ILs catalytic systems.•Understanding the alkylation process by combining experiment and COSMO-RS model. Using coal-based feedstocks to produce chemicals is of importance for the high value-added utilization of coal and the reduction of petroleum consumption. Alkyltetralins similar to naphthenic oil were successfully obtained through tetralin alkylation with various olefins. Various ionic liquids (ILs) were applied to catalyze alkylations, and Et3NHCl-AlCl3 IL exhibited high catalytic activity under mild reaction temperature (80 °C), the selectivity of multi-alkyltetralins higher than 70% could be achieved at >99% tetralin conversion. Such catalyst was shown to be robust in the presence of trace water and oxygenated chemicals. COSMO-RS model was applied to predict the mutual solubility and interaction of tetralin, olefins and alkyltetralins in ILs. The experimental and calculated results demonstrated that the favorable interactions of shorter-chain olefins and ILs benefited to produce multi-alkyltetralins, and the low mutual solubility of reactants and products in ILs was helpful to the rapid separation of products in the system.