Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, fl...Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, flow Hammett indicator method and chemical analysis. Their catalytic activities in esterification reaction of acetic acid with n-butanol were studied. The results showed that ZrO2 in the catalysts mainly in tetragonal phase and few in monoclinic phase. The tetragonal phase of ZrO2 and S2O 2-8 are the key factors that guarantee the catalytic activity. Incorporation of appropriate amounts of metallic oxides（Cr2O3,Ce2O3,La2O3） into the catalyst favors the stabilization of sulfur species and surface area, which increase the activity sites on the catalyst. The experimental results showed that three catalysts S2O 2-8/ZrO2-Al2O3（2%）-M2O3（1%）（M=Cr,Ce,La） had higher catalytic activity in mentioned esterification, with the conversion of acetic acid reached 96.8%, 95.7% and 96.1%, respectively. The preparation condition of the catalysts showed great influence on the catalytic activity.展开更多
Sulfated zirconia-lanthana （SO4^2-/ZrO2-La2O3） precursors were prepared by ultrasonic coprecipitation method and followed by aging at different temperature. The precursors were treated by 0.5 mol/L H2SO4. Samples of...Sulfated zirconia-lanthana （SO4^2-/ZrO2-La2O3） precursors were prepared by ultrasonic coprecipitation method and followed by aging at different temperature. The precursors were treated by 0.5 mol/L H2SO4. Samples of SO4^2-/ZrO2-La2O3 nano-crystalline catalysts were obtained by baking the treated precursors at different temperatures. The acidic properties of SO4^2-/ZrO2-La2O3 were tested by the Hammett indicator method. The phase composition, specific area, particle structure, and surface state were characterized by X-ray diffraction, BET, transmission electron microscopy, infrared spectrum, and X-ray photoelectron spec- troscopy. The catalytic activities were estimated by esterification of acetic acid with glycerin. It was shown that the catalyst prepared by ultrasonic stirring and low temperature （-15 ℃） exhibited highly active sites and high catalytic property.展开更多
A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures an...A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.展开更多
文摘Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, flow Hammett indicator method and chemical analysis. Their catalytic activities in esterification reaction of acetic acid with n-butanol were studied. The results showed that ZrO2 in the catalysts mainly in tetragonal phase and few in monoclinic phase. The tetragonal phase of ZrO2 and S2O 2-8 are the key factors that guarantee the catalytic activity. Incorporation of appropriate amounts of metallic oxides（Cr2O3,Ce2O3,La2O3） into the catalyst favors the stabilization of sulfur species and surface area, which increase the activity sites on the catalyst. The experimental results showed that three catalysts S2O 2-8/ZrO2-Al2O3（2%）-M2O3（1%）（M=Cr,Ce,La） had higher catalytic activity in mentioned esterification, with the conversion of acetic acid reached 96.8%, 95.7% and 96.1%, respectively. The preparation condition of the catalysts showed great influence on the catalytic activity.
文摘Sulfated zirconia-lanthana （SO4^2-/ZrO2-La2O3） precursors were prepared by ultrasonic coprecipitation method and followed by aging at different temperature. The precursors were treated by 0.5 mol/L H2SO4. Samples of SO4^2-/ZrO2-La2O3 nano-crystalline catalysts were obtained by baking the treated precursors at different temperatures. The acidic properties of SO4^2-/ZrO2-La2O3 were tested by the Hammett indicator method. The phase composition, specific area, particle structure, and surface state were characterized by X-ray diffraction, BET, transmission electron microscopy, infrared spectrum, and X-ray photoelectron spec- troscopy. The catalytic activities were estimated by esterification of acetic acid with glycerin. It was shown that the catalyst prepared by ultrasonic stirring and low temperature （-15 ℃） exhibited highly active sites and high catalytic property.
文摘A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.
