Simultaneous Measurement of Intracrystalline Diffusion in Molecular Sieve Zeolites by NMR and Gravimetric Methods

研究内容：研究了聚乙烯的扩散和吸附性能， 通过以下方法研究了高硅沸石上的碳氢化合物 重量分析和核磁共振方法来解决的差异， 扩散测量，这是在文献中报道， 测量之间的几个数量级 这两种技术，为了获得基本的理解， 沸石中的扩散。 新奇：正在建造并将使用新装置 对相同的沸石进行同时扩散测量， 样品，在完全相同的条件下， 相同的吸附压力，使用NMR和重量分析法。 这种独特的测量方法将使其能够 将微观核磁共振测量的结果与 从宏观重力测量，从而解决 目前存在较大分歧。 技术影响：从拟议的 这项工作不仅将提供基本的了解， 沸石的运输和吸附性能，而且还将是 在改善工程设计的重要性， 操作如气流的纯化，分离过程， 和催化转化单元。 更好地理解 扩散机制和平衡性质可以提供 在理解催化行为的有价值的信息 用于实际工业的择形沸石 例如二甲苯异构化、脱蜡和 甲醇转化为汽油。

Research Summary: The diffusive and adsorptive properties of hydrocarbons on high-silica zeolites are investigated by gravimetric and NMR methods to resolve the differences in diffusion measurements, which are reported in the literature to be of several orders of magnitude between measurements made by these two techniques, in order to gain fundamental understanding of diffusion in zeolites. Novelty: A new apparatus is being constructed and will be used to make simultaneous diffusion measurements of identical zeolite samples, activated under exactly the same conditions, under identical sorbate pressure, using NMR and gravimetric methods. This unique method of measurement will make it possible to compare the results from microscopic NMR measurements to those from macroscopic gravimetric measurements, thus resolving currently existing large differences. Technical Impact: The information obtained from the proposed work will not only provide fundamental understanding of the transport and adsorption properties of zeolites but also will be of importance in improving engineering design in such important operations as purification of gas streams, separation processes, and catalytic conversion units. A better understanding of the diffusion mechanisms and equilibrium properties can provide valuable information in understanding catalytic behavior of shape-selective zeolites used in practical industrial applications such as xylene isomerization, dewaxing and conversion of methanol to gasoline.