Carbonylation of aryl halide catalyzed by active-carbon supported ionic liquid-phase palladium catalyst

Highly dispersed supported ionic liquid-phase palladium catalyst was prepared and its catalytic performances for carbonylation of aryl halide were investigated. Active-carbon supported ionic liquid-phase palladium catalyst was characterized by XRD, high-resolution TEM(HRTEM), and XPS. The results showed that the active-carbon supported ionic liquid-phase palladium catalyst was reduced to zero valence and that the average particle diameter of the Pd crystallites was less than 5 nm. A thin ionic liquid film was observed on the surface of the catalyst. The results indicated that the supported ionic liquid-phase palladium catalyst exhibited higher activity in the carbonylation of aryl halides compared with the correspording organic-ionic liquid biphasic system. Under the optimum reaction conditions: 140 degrees C, p(co)=4.0 MPa, n(PhI):n(Pd)=10528:1, the turnover frequency(TOF) of 4926 h(-1) was achieved for ethyl benzoate, with the conversion of 99.3%, and the selectivity for forming ethyl benzoate was more than 99%.