Preparation of high-quality alkylated gasoline with low alkane-to-alkene ratio catalyzed by polyether-based Brønsted-Lewis acidic deep eutectic solvent

[Display omitted] •The polyether chains improve the solubility of isobutane.•The bonding between polyether and isobutane is simulated by DFT.•Polyether-based acidic DES can catalyze isobutane/isobutene alkylation.•High-quality alkylated gasoline is afforded under a low alkane-to-alkene ratio.•DES catalyst exhibits good recycling capacity. In this study, the solubility of isobutane in different types of polyethers was evaluated. Macroscopic and microscopic simulations of molecular bonding of isobutane to polyethers such as PEG200 and PPG200 were performed. The solubility of isobutane in different polyethers with different degrees of polymerization was investigated. The solubility of isooctane—the main alkylated gasoline product—in different polyethers was also determined. Based on the solubility ratios of isobutane and isooctane in the same polyether, PEG200 was selected as a component of a deep eutectic solvent (DES), which was then used for catalyzing the alkylation of isobutane and isobutene to prepare alkylated gasoline. Owing to the good solubility of isobutane in polyether, a three-component Brønsted–Lewis acidic DES catalyst, InCl3/PEG200/TfOH, could be used to prepare high-quality alkylated gasoline (conversion rate: 89.12%, C8 selectivity: 82.83%) at a low alkane-to-alkene ratio (5:1). Moreover, owing to its poor solubility to isooctane, the DES catalyst could be easily separated from alkylated gasoline. This DES catalyst retains its high catalytic activity over seven cycles.