Effect of tin on Nb2O5/α-Al2O3 catalyst for ethylene oxide hydration
Effect of tin on Nb2O5/α-Al2O3 catalyst for ethylene oxide hydration
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DOI：
10.1016/j.jcat.2006.04.030
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发表时间：
2006-07
影响因子：
7.3
通讯作者：
Yingcheng Li;Shirun Yan;Linping Qian;Weimin Yang;Zaiku Xie;Qingling Chen;B. Yue;Heyong He
中科院分区：
文献类型：
--
作者：
Yingcheng Li;Shirun Yan;Linping Qian;Weimin Yang;Zaiku Xie;Qingling Chen;B. Yue;Heyong He
通过X射线衍射、拉曼光谱、NH_3-TPD、吡啶红外光谱、H2O吸附等表征手段，研究了TiN对Nb_2O_5/α-Al_2O_3催化剂的结构、酸性、吸水性能以及对环氧乙烷(EO)水合反应性能的影响。表征结果表明，在所研究的样品中，随着TiN的加入和锡/Nb比的增加，酸性中心密度降低，而在锡/Nb=0.08时酸性强度最小。吸附水的红外光谱表明，TiN的加入显著提高了催化剂的吸水性能。催化试验表明，单甘醇选择性从Nb2O5/α-Al2O3催化剂的89.8%提高到锡助剂催化剂的94.0%，环氧乙烷转化率保持在99.7%，且具有良好的稳定性。结果表明，TiN促进的催化剂的吸水性能增强是显著提高MeG选择性的原因。
The effect of tin on the structure, acidity, and water adsorption property of Nb2O5/α-Al2O3catalyst and on this catalyst's performance for ethylene oxide (EO) hydration were studied by XRD, Raman spectroscopy, NH3-TPD, IR of pyridine and of H2O adsorption, and catalytic tests. Characterization results revealed that the density of acidic sites decreased with the addition of tin and with increasing Sn/Nb ratio in the cases studied, whereas the acidity exhibited minimum strength at Sn/Nb=0.08. The IR of water adsorption indicated that addition of tin significantly enhanced the water adsorption property of the catalyst. The catalytic tests revealed that monoethylene glycol (MEG) selectivity increased from 89.8% of the Nb2O5/α-Al2O3catalyst to 94.0% of the tin-promoted catalyst maintaining the EO conversion at 99.7%, and the catalyst exhibited excellent stability. The enhanced water adsorption property of the tin-promoted catalyst is proposed to be responsible for the significant improvement in MEG selectivity.