A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts c...A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts calcined at different temperatures were characterized using NH3-TPD, pyridine-FTIR, X-ray diffraction, and Raman techniques. It was found that the calcination process could not only change the structure of these catalysts but also modify the amount of surface acidity on the catalysts. The catalyst calcined at 400 ℃ exhibited the highest conversion of acetylene （94.6%） and highest selectivity to vinyl fluoride （83.4%） and lower coke deposition selectivity （0.72%）. The highest activity was related to the largest amount of surface acidity on the catalyst, and the coke deposition was also related to the total amount of surface acidic sites.展开更多
To address the limitations of the separate fluoride removal or detection in the existing materials,herein,amino-decorated metal organic frameworks NH_(2)-MIL-53(Al)have been succinctly fabricated by a sol-hydrothermal...To address the limitations of the separate fluoride removal or detection in the existing materials,herein,amino-decorated metal organic frameworks NH_(2)-MIL-53(Al)have been succinctly fabricated by a sol-hydrothermal method for simultaneous removal and determination of fluoride.As a consequence,the proposed NH_(2)-MIL-53(Al)features high uptake capacity(202.5 mg/g)as well as fast adsorption rate,being capable of treating 5 ppm of fluoride solution to below the permitted threshold in drinking water within 15 min.Specifically,the specific binding between fluoride and NH_(2)-MIL-53(Al)results in the release of fluorescent ligand NH2-BDC,conducive to the determination of fluoride via a concentration-dependent fluorescence enhancement effect.As expected,the resulting NH_(2)-MIL-53(Al)sensor exhibits selective and sensitive detection(with the detection limit of 0.31μmol/L)toward fluoride accompanied with a wide response interval(0.5-100μmol/L).More importantly,the developed sensor can be utilized for fluoride detection in practical water systems with satisfying recoveries from 89.6% to 116.1%,confirming its feasibility in monitoring the practical fluoride-contaminated waters.展开更多
A new azopyrrole compound, 1, has been synthesized and characterized. The crystal of 1 is of monoclinic system, space group P21/c with a = 8.7167（9）, b = 17.5929（19）, c = 12.8096（15） ？, β = 97.565（2）o, V = 1...A new azopyrrole compound, 1, has been synthesized and characterized. The crystal of 1 is of monoclinic system, space group P21/c with a = 8.7167（9）, b = 17.5929（19）, c = 12.8096（15） ？, β = 97.565（2）o, V = 1947.3（4） ^3, Z = 4, C（20）H（26）N4O2, Mr = 354.45, Dc = 1.209 g/cm^3, F（000） = 760 and μ（Mo Kα） = 0.080 mm^-1. In the crystal, 1 binds one methanol molecule through N–H…O, O–H…O and O–H…π interactions. UV-Vis titration and 1H NMR titration studies reveal that compound 1 can selectively detect fluoride ion in the DMSO solution.展开更多
Calcium fluoride nanoparticles were synthesized by water/cetyltrimethylammonium bromide (CTAB)/2-octanol microemulsion systems. X-ray powder diffraction analysis showed that the products were a single phase. The resul...Calcium fluoride nanoparticles were synthesized by water/cetyltrimethylammonium bromide (CTAB)/2-octanol microemulsion systems. X-ray powder diffraction analysis showed that the products were a single phase. The result of scanning electron microscopy confirmed that the average sizes of the calcium fluoride particles were below 100 nm in diameter. With decreasing water content and reaction time, the particle sizes decreased.展开更多
基金ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China （No.20873125）,
文摘A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts calcined at different temperatures were characterized using NH3-TPD, pyridine-FTIR, X-ray diffraction, and Raman techniques. It was found that the calcination process could not only change the structure of these catalysts but also modify the amount of surface acidity on the catalysts. The catalyst calcined at 400 ℃ exhibited the highest conversion of acetylene （94.6%） and highest selectivity to vinyl fluoride （83.4%） and lower coke deposition selectivity （0.72%）. The highest activity was related to the largest amount of surface acidity on the catalyst, and the coke deposition was also related to the total amount of surface acidic sites.
基金supported by the National Key R&D Program of China(No.2017YFA0207202)the National Natural Science Foundation of China(No.51572263,No.51772299,No.41701259).
文摘To address the limitations of the separate fluoride removal or detection in the existing materials,herein,amino-decorated metal organic frameworks NH_(2)-MIL-53(Al)have been succinctly fabricated by a sol-hydrothermal method for simultaneous removal and determination of fluoride.As a consequence,the proposed NH_(2)-MIL-53(Al)features high uptake capacity(202.5 mg/g)as well as fast adsorption rate,being capable of treating 5 ppm of fluoride solution to below the permitted threshold in drinking water within 15 min.Specifically,the specific binding between fluoride and NH_(2)-MIL-53(Al)results in the release of fluorescent ligand NH2-BDC,conducive to the determination of fluoride via a concentration-dependent fluorescence enhancement effect.As expected,the resulting NH_(2)-MIL-53(Al)sensor exhibits selective and sensitive detection(with the detection limit of 0.31μmol/L)toward fluoride accompanied with a wide response interval(0.5-100μmol/L).More importantly,the developed sensor can be utilized for fluoride detection in practical water systems with satisfying recoveries from 89.6% to 116.1%,confirming its feasibility in monitoring the practical fluoride-contaminated waters.
基金supported by the National Natural Science Foundation of China(No.21172174)
文摘A new azopyrrole compound, 1, has been synthesized and characterized. The crystal of 1 is of monoclinic system, space group P21/c with a = 8.7167（9）, b = 17.5929（19）, c = 12.8096（15） ？, β = 97.565（2）o, V = 1947.3（4） ^3, Z = 4, C（20）H（26）N4O2, Mr = 354.45, Dc = 1.209 g/cm^3, F（000） = 760 and μ（Mo Kα） = 0.080 mm^-1. In the crystal, 1 binds one methanol molecule through N–H…O, O–H…O and O–H…π interactions. UV-Vis titration and 1H NMR titration studies reveal that compound 1 can selectively detect fluoride ion in the DMSO solution.
文摘Calcium fluoride nanoparticles were synthesized by water/cetyltrimethylammonium bromide (CTAB)/2-octanol microemulsion systems. X-ray powder diffraction analysis showed that the products were a single phase. The result of scanning electron microscopy confirmed that the average sizes of the calcium fluoride particles were below 100 nm in diameter. With decreasing water content and reaction time, the particle sizes decreased.
