• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1154-1158
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• 2012

A room-temperature ionic liquid (RTIL) derived from 1,4-diazabicyclo[2.2.2]octane (DABCO) consisting of tetrafluoroborate anion, 1-butyl-4-(4-sulfonylbutyl)-1,4-diazoniabicyclo[2.2.2]octane hydrogen sulfate tetrafluoroborate ($[C_4DABCOC_4SO_3H][BF_4][HSO_4]$) was synthesized and catalytically evaluated in the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by cyclocondensation reaction of ${\beta}$-naphthol and aryl aldehydes. This novel RTIL with an acidic $SO_3H$ group showed high catalytic activity with good to excellent yields of the desired products in short reaction times. Moreover, the catalyst could be recovered and reused at least three times with only slight reduction in its catalytic activity.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2311-2315
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• 2011

Alumina supported polyphosphoric acid (PPA/$Al_2O_3$) was successfully prepared by impregnation of alumina support by polyphosphoric acid and characterized using FT-IR spectroscopy, the $N_2$ adsorption/desorption analysis (BET), thermal analysis (TG/DTG), and X-ray diffraction (XRD) techniques. The catalytic behavior of this new solid acid supported heterogeneous catalyst was checked in the synthesis of 14-aryl-14H-dibenzo[a, j]xanthenes by cyclocondensation reaction of ${\beta}$-naphthol and aryl aldehydes under solvent-free conditions. The results showed that the novel catalyst has high activity and the desired products were obtained in very short reaction times with high yields. Moreover, the catalyst can be easily recovered by filtration and reused at least three times with only slight reduction in its catalytic activity.