| 许章林,张盈珍,郑禄彬.杂原子沸石的二次合成及其表征——Ⅰ.含稼Y沸石[J].分子催化,1992,(4): |
| 杂原子沸石的二次合成及其表征——Ⅰ.含稼Y沸石 |
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| DOI： |
| 中文关键词: 类质同晶取代,Y佛石,空穴羟基 |
| 英文关键词:Isomorphous substitution, Zeolite Y, Defect hydroxyl., |
| 基金项目: |
| 许章林 张盈珍 郑禄彬 |
| 中国科学院大连化学物理研究所，中国科学院大连化学物理研究所，中国科学院大连化学物理研究所 大连 116023，大连 116023，大连 116023 |
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| 中文摘要: |
| 以Y型沸石为原料,(NH_4)_3GaF_6为取代剂,进行液一固类质同晶取代反应,成功地制备出骨架含Ga的[Ga]Y系列沸石,并用化学分析、IR、XRD、DTA等多种方法进行了表征。与(NH_4)_2SiF_6对Y沸石的脱Al补Si不同,脱Al补Ga反应可以在取代剂Ga/沸石中Al(原子比)大于1.0条件下进行,沸石达到高度脱Al补Ga,但仍维持良好的结晶度,[Ga]Y的空穴浓度几无增加,部分Ga处于骨架外,不为NH_4Cl所交换,Ga进入Y沸石后,其晶胞参数增大,热稳定性下降,红外骨架振动频率向低频位移,B酸酸量减少,L酸酸量增加,且变化程度与Ga对Al的取代程度有对应关系。 |
| 英文摘要: |
| In this paper a new method of producing [Ga]Y by isomorphous substitution between zeolite Y and (NH4)GaF6 solution is reported. Varying the ratio of Ga mol/Al mol in the reaction, zeolites [Ga]Y with different Ga contents have been produced. In order to verify the incorporation of Ga into the framework, measurements including chemical analysis, IR, XRD and DTA have been taken. Highly crystalline and substitutional zeolite [Ga]Y is produced under the substitution condition of Ga mol/Al mol>l. 0, and this is different from the reaction between zeolite Y and (NH4)2SiF6 solution. Except for [Ga]Y4 which contains 26. 93 wt% Ga, all samples show a high X-ray crystallinity. The reduced intensity of [Ga]Y is probably due to the absorption of X-ray by the heavier and much larger Ga atoms. In the XRD spectra of samples, no new reflections due to other crystalline phase are observed. The DTA results show that the crystal collapse temperatures of all samples decline after the substitution reaction, and the higher Ga content in zeolite, the lower DTA temperature it shows. In addition, the IR spectra of [Ga]Y show only a slight increase in the defect hydroxyl region. Part of the gallium cations are located in the extraframework of the samples and they can not be removed by ammonium ion exchange. It is also found that the incorporation of Ga into zeolite Y leads to an increase in the unit cell parameter and red shifts of the symmetric and asymmetric stretching vibration frequencies , as well as a decrease of B acidity and an increase of L acidity. The variations of these characteristics are corresponding to the degree of substitution of Ga for Al. |
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