| Ω型分子筛中两种结晶学不等价四面体位上的铝分布 |
| Al-DISTRI BUTIONS ON TWO CRYSTALLOGRAPHICALLY NONEQU IVALENT TETRAHEDRAL SITES IN ZEOLITE OMEGA |
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| 摘要: 本文用Monte Carlo模拟实现Ω型分子筛中硅铝分布的物理模型,把由此计算获得的{Sik(nAl)}结构单元相对数量与29Si MAS NMR实验及Klinowski等的统计计算结果相比较,无论是B位{SiB(nAl)},还是A位{SiA(nAl)}分布,从总体上全面的逼近NMR实验分析值.对铝浓度不很高时29SiMAS NMR实验分析呈现出的IsiB(2Al)>IsiB(1Al)的令人费解的情况,也得到了初步阐明.这说明,本文提出的TB位硅有同时桥联两个骨架铝原子的倾向假设是合理和自洽的,也是影响Ω型分子筛中硅、铝分布的一个因素. |
| 关键词: Ω型分子筛 硅、铝分布 Monte Carlo 方法 |
| 基金项目: |
| Abstract: In the present work,several models of the Si, Al distribution on the framework of Zeolite Omega are studied. The relative populations of {Sik(nAl)}(k=A,B;n=0-4) building units are calculated in terms of the Monte Carlo simulation for each distribution model. The calculated results are compared with both the experimental analytical data of 29Si MAS NMR and the statistical calculations by Klinowski et al.In model-3 of us, besides the "Loewenstein rule" and a consideration of the tendency of "the next-nearest-neighbor avoidance" among Al atoms, we assumed further that the SiB tends to connect, via oxygen bridges, two Al atoms as its nearest-neighbors. The calculated results of model-3 gained a great deal of improvements namely not only the distribution of {SiB(nAl)},but also the distribution of {SiA(nAl)} closed ovcrally to the experimental data.As the Al concentrations are not very high the experimental data of Si MAS NMR showed that IsiB(2Al)> IsiB(lAl) which had been a puzzlement were explained perliminarily. |
| Keywords: zeolite omega Si Al distribution Monte Carlo method |
| 投稿时间：1991-08-09 |
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| 孙平川,李子元,金庆华,王敬中,丁大同,胡澄.Ω型分子筛中两种结晶学不等价四面体位上的铝分布[J].无机化学学报,1993,9(1):53-58. |
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