High Catalytic Performance of Mesoporous Dual Brønsted Acidic Ternary Poly (Ionic Liquids) for Friedel-Crafts Alkylation

A newfangled cross-linked dual Brønsted acidic ternary mesoporous poly (ionic liquids)(MPILs) with mesoporous structure was successfully synthesized with divinylbenzene as cross linker, 1-vinyl-3-butyl imidazole bromide and sodium p-styrene sulfonate as functional group through an ordinary post-modification method and anion exchange process. A sponge-like mesoporous tunnel structure was observed and the obtained P (BVS-SO 3 H)-SO 3 CF 3 sample appeared a relatively high thermal stability, a large surface area (up to 286.8 m 2 /g) and great pore volume (0.73 cm 3 /g). The abundant dual acidic group of sulfonic acid and trifluoromethanesulfonic acid of the composite in the polymer framework impart Brønsted acidity. For the sake of demonstrating our claims, the sample has been used as a novel solid acid catalyst for the reaction of alkylation of o-xylene with styrene to 1-diphenylethane (PXE). Under optimal reaction conditions (reaction under 120 °C for 3 hr, catalyst amount was 0.5 wt% of the reaction system, and the mass ratio of o-xylene/styrene was 7.5:1, a 100% conversion of styrene and 93.7% PXE yield was acquired. After four times recycle, the yield remains 53.3%. Comparing with the commercial liquid acid catalyst, it processing a higher catalytic property and recyclability. Moreover, this fresh dual acidic heterogeneous catalyst owning a promising future applied in other acidic catalytic reactions and provide a new method to modify catalyst.