文摘
Novel Keggin heteropolyacid anion based Br酶nsted acidic ionic salts [SO3H(CH2)4Mim]nH3鈥?i>nPMo12O40 (n = 1, 2, 3) were synthesized and used as catalysts in the nitration of aromatic compound in HNO3 (67%). The catalytic activity was in the order of [(CH2)4SO3HMim]3PMo12O40 > [(CH2)4SO3HMim]2HPMo12O40 > [(CH2)4SO3HMim]H2PMo12O40. The effect of catalyst loading, quantity of nitro acid and temperature on nitration of toluene was discussed, and 87.7% yield and good para selectivity with 1.19 ratio of ortho to para can be obtained with optimized catalyst [(CH2)4SO3HMim]3PMo12O40. The catalyst can be easily separated from the products and recycled for three times without significant loss of activity.