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用离子交换法制备了不同稀土含量的Y型分子筛(REY)。X射线衍射分析表明稀土离子已进入分子筛的晶格位置,衍射谱上未出现稀土氧化物的特征衍射峰。用NH3程序升温热脱附法和吡啶红外光谱法研究了分子筛的酸性。结果表明,与稀土含量较低的Y型分子筛相比,高稀土含量的分子筛拥有较少的Lewis酸中心(151μmol.g-1)和较多的强酸中心。由稀土Y型分子筛制备的模型催化剂的反应性能进一步反映了分子筛酸性随稀土含量的变化规律,随着稀土含量的增加,催化剂的重油产率由5.93%降低到5.15%。此外,吡啶环变形模ν19b红外光谱间接证明了稀土离子有抑制骨架Al原子脱出的作用。
Y-type molecular sieves (REYs) with different RE contents were prepared by ion exchange method. X-ray diffraction analysis showed that the rare earth ions have entered the lattice position of the molecular sieve, the diffraction spectrum does not appear characteristic diffraction peaks of rare earth oxides. The acidity of the molecular sieve was studied by NH3 temperature-programmed thermal desorption and pyridine-IR spectroscopy. The results show that zeolite with high RE content possesses less Lewis acid center (151μmol.g-1) and more strong acid sites than Y zeolite with lower RE content. The reactivity of the model catalyst prepared from the rare earth Y zeolite further reflects the change of acidity of the molecular sieve with the content of rare earth. With the increase of rare earth content, the yield of heavy oil of the catalyst decreased from 5.93% to 5.15%. In addition, the pyridine ring deformation mode ν19b infrared spectroscopy indirect proof rare earth ions inhibit the skeleton Al atoms prolapse role.