Requlation and Cotolysis of Strong Solid Acid Generated on Extra-Framework Aluminum

用高铝含量的Y型和丝光沸石型样品精确测定了沸石的酸性与组成之间的关系。在实验范围内，表示酸量的解吸氨的数量与[Al]-[Na]原子的数量大致相同。这与常规观察到的形成二次相邻铝物质的关系完全不同。指出即使铝原子位于次邻位，沸石中的同晶取代铝也会按化学计量比产生酸中心，在氨的程序升温脱附实验中，在ZSM-5沸石上观察到很强的酸中心。该位点可归因于非骨架铝，其与通常的骨架酸位点相互作用。通过铝离子的浸渍，以牺牲分子筛骨架上的酸性中心为代价，形成了强酸性中心，模板剂分子脱除步骤的条件对HZSM-5中强酸性中心的浓度有很大影响。在约373 K的氨与水的处理也进行了研究，作为一个程序，影响固体酸度，并确定了由这两种方法创建的酸位点的相似性。从酸中心的定量测量，它被发现，非常强的酸中心由两个铝阳离子。超强酸中心的存在提高了催化剂的辛烷裂解活性，超稳Y型分子筛经Na_2H_2-乙二胺四乙酸处理后，形成了对烷烃裂解具有活性的强B酸中心，其酸强度分布窄，数量多。

The relationship between the acidic property and the composition of a zeolite was precisely measured using Y-and mordenite-type samples with high aluminum contents. The number of the desorbed ammonia, showing the acid amount, was approximately same to the number of [Al]-[Na] atoms over the experimental range. This is quite different from the conventionally observed relationship where the secondary-neighboring aluminum species is formed. It is pointed out that the isomorphously substituted aluminum in zeolite generates the acid site according to the stoichiometry even when the aluminum atoms locate the secondary-neighboring sites.Very strong acid site was observed on the zeolite ZSM-5 in measurements of temperature programmed desorption of ammonia. The site was ascribable to the non-framework aluminum, which interacted with the usual framework acid site. By impregnation of aluminum cation, the strong acid site was created at the expense of the acid site in a zeolite framework.Conditions of a step for template molecule removal affected strongly the concentration of very strong acid site in HZSM-5. Treatment with ammonia with water at ca 373 K was also studied as a procedure to affect the solid acidity, and a similarity of acid sites created by both methods was identified. From the quantitative measurements of acid sites, it was found that the very strong acid site consisted of two Al cations. Catalytic activity for octane cracking was enhanced by the presence of very strong acid site.Strong Bronsted acid site with a narrow distribution of acid strength and large amount, which was active for alkane cracking, was formed by Na_2H_2-ethylenediaminetetraacetic acid treatment of ultra stable Y zeolite.