PrAlPO-5 with (Al+P)/Pr ratios of 25, 50, 75 and 100 molecular sieves were successfully synthesized by hydrothermal method. These molecular sieves were characterised using XPS, TPD-NH3, ex-situ pyridine adsorbed IR, TPR, TGA, 27Al and 31P MAS-NMR and ESR studies. The incorporation of praseodymium in the framework of AlPO-5 was confirmed by XRD, DRS UV-vis and 27Al and 31P MAS-NMR analysis. ESR spectrum showed the presence of adsorbed oxygen. The nature and strength of acid sites were identified by ex-situ pyridine adsorbed IR and TPD-NH3. The BET surface area was found to be in the range of 238−272 m2 g−1. The catalytic activity of the molecular sieves was tested for the liquid phase aerobic oxidation of ethylbenzene. Acetophenone was found to be the major product with more than 90% ethylbenzene conversion. ICP-OES analysis revealed the presence of praseodymium intact in the framework of AlPO-5 up to five cycles.
通过
水热法成功合成了具有不同(Al+P)/Pr比的PrAlPO-5
分子筛(25、50、75和100)。这些
分子筛通过XPS、
TPD-NH3、原位
吡啶吸附红外、TPR、TGA、27Al和31P MAS-NMR以及ESR等方法进行了表征。XRD、DRS UV-vis和27Al及31P MAS-NMR分析证实了
镨在AlPO-5骨架中的掺入。ESR光谱显示存在吸附氧。通过原位
吡啶吸附红外和
TPD-NH3鉴定了酸位的性质和强度。BET比表面积在238−272 m² g⁻¹范围内。这些
分子筛的催化活性在乙苯液相空气氧化反应中进行了测试。发现
苯乙酮为主要产物,乙苯转化率超过90%。ICP-OES分析显示,在AlPO-5骨架中
镨的存在保持完整,经过五个循环周期。