【摘要】 在铵交换度为27～98%、超稳化处理温度为550～800℃、有或无后铵交换条件下,用NaY分子筛制备了样品。从分子筛骨架振动及羟基伸缩振动的红外光谱特征谱带、吡啶为探针分子的不同脱附温度下1550和1450cm^-1附近红外光谱谱带、X射线衍射法测得的晶胞常数α₀、DTA分析法测得的沸石结构破坏放热峰温度,对样品进行了表征,研究了USY制备中脱铝、稳定化和酸性变化的规律,对稳定化过程的有关问题进行了讨论。更多还原

【Abstract】 For a series of NH₄⁺ ion exchanged NaY （0～98%）, hydrothermal treatment at different temperatures （550-800%]） have been conducted. The hydrothermally treated samples （USY） and their further NH₄⁺ （or NH₄⁺ and H⁺） ion exchanged forms （USHY） have been characterized by IR, X-Ray and DTA methods.As the extent of NH₄⁺ exchange of the sample increased and the treatment severity increased, the skeletal vibration bands shifted to higher frequencies, and unit cell parameters a0 decreased monotonously. Simultaneously, the crystal collapse temperatures raised. Some dealumination of these samples took place, which was correlated with their stability. The acidity and acid strength of both Bronsted and Lewis acids measured by IR decreased as the treatment temperature raised. However, as the extent of NH₄⁺ exchange of the sample increased, the acidity of both acids increased. For the USHY samples, their acidity can be regulated to a large extent, depending upon the nature of the starting materials and the conditions used. The dehydroxylation of the NH₄NaY samples under hydrothermal treatment have been observed by IR. From the observation of the hydroxyl bands and their changes on pyridine adsorption, the possible origins of the protonic acidity on the USY were deduced. The regularities which appeared have been discussed.更多还原