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
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
A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of app...A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows： calcination temperature of the catalyst 600 ℃, n（lactic acid）：n（n-butyl alcohol）=1.0：3.0, w（S2O8^2-/ZrO2- CeO2）=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.展开更多
The system of the catalyst S2O82-/ZrO2-SiO2-Sm2O3 were studied by IR,and the effect on the catalyst characters by different Si/Zr atom ratio,immersing solution and rare earth were studied.The result showed that the ca...The system of the catalyst S2O82-/ZrO2-SiO2-Sm2O3 were studied by IR,and the effect on the catalyst characters by different Si/Zr atom ratio,immersing solution and rare earth were studied.The result showed that the catalyst has the best activity when the Si/Zr atom ratio is 15%,3.0% Sm2O3 and immersing solution was S2O82- instead of SO42-.The deduction of S2O82- maybe formed a bridge structure with Zr not with Si were explained well here.展开更多
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.
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.
基金supported by the Science and Technique Foundation of Shaaxi Province of China (2008K07-32)the Foundation of Shaanxi Educa- tional Committee of China (08JK228)the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows： calcination temperature of the catalyst 600 ℃, n（lactic acid）：n（n-butyl alcohol）=1.0：3.0, w（S2O8^2-/ZrO2- CeO2）=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.
文摘The system of the catalyst S2O82-/ZrO2-SiO2-Sm2O3 were studied by IR,and the effect on the catalyst characters by different Si/Zr atom ratio,immersing solution and rare earth were studied.The result showed that the catalyst has the best activity when the Si/Zr atom ratio is 15%,3.0% Sm2O3 and immersing solution was S2O82- instead of SO42-.The deduction of S2O82- maybe formed a bridge structure with Zr not with Si were explained well here.
