新型重整催化剂的研究——Pt／L中沸石酸碱性的作用

Ｐｔ／ＫＬ、Ｐｔ／ＢａＫＬ及Ｐｔ／ＨＬ上的铂与沸石的酸碱位发生相互作用，导致催化剂上存在不同电子状态和粒度分布的铂位，从而产生有着完全不同催化作用、不同抗硫性能的两类催化剂，即以碱性沸石为载体的“单功能”催化剂和以酸性沸石为载体的“双功能”催化剂。在Ｐｔ／ＫＬ、Ｐｔ／ＢａＫＬ催化剂上，存在着对硫敏感的具有环化脱氢功能和对硫不敏感的仅具有脱氢功能的两类铂活性位。     

Synthesis and Characterization of Nanosized ZSM-5 Zeolite with Mesoporous Carbon Nanotube as Templates

Preparation of nanocrystalline ZSM-5 has been proven possible with carbon matrix by using confined space synthesis. In combination with the hydrothermal method, by the use of a mesoporous carbon nanotube as the inert support material, ZSM-5 with SiO₂/Al₂O₃ ratios of 100 was successfully synthesized with an average crystal size of 27 nm. Their structures were preliminarily characterized by x-ray power diffraction (XRPD) and infrared spectroscopy (IR), and scanning electron microscopy (SEM), respectively. At the same time, we put forward the mechanism about the confined space synthesis in terms of the results.     

Natural zeolite utilisation in pollution control: A review of applications to metals' effluents

This paper assesses the potential of natural zeolite utilization as a low-cost ion-exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost-effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology.     

钛硅选择性氧化催化剂的研究进展

过渡金属钼、钨、钛、钒等的高价态络合物能有效催化有机过氧化物进行烯烃的环氧化反应。以Ｍｏ（Ⅵ）络合物在有机相中催化过氧化烃来氧化丙烯生产环氧丙烷的方法称之为间接氧化法，是生产环氧丙烷的主要方法之一。７０年代初，荷兰Ｓｈｅｌ研究所发现Ｔｉ（Ⅳ）高分散负...     

Methanol adsorption and dehydration on alkali metal exchanged NaY zeolites

FT-IR spectroscopy has been applied in a study of methanol adsorption on M^INaY zeolites (M=Li, K, Rb, Cs). Coordinatively and/or hydrogen bonded methanol was registered in the temperature range 300–473 K. Dehydration of methanol to dimethyl ether occurred at 573 and 623 K. It was found that the activity of the catalyst for methanol dehydration strongly depends on the kind of alkali metal cation, and well correlates the IR data relative to methanol adsorption.     

Pyrene oxidation as a model reaction for characterizing the mechanism of coke oxidation on Y zeolites

The same effect of temperature on the production of CO, CO₂ and H₂O was found during oxidative treatment of HY zeolites either impregnated with pyrene or coked. Therefore, pyrene oxidation can be used to specify the mechanism of coke oxidation. Three types of reactions can be distinguished: (a) condensation of polyaromatic molecules, (b) oxidation of polyaromatics into aldehydes, ketones, acids and anhydrides and (c) decarbonylation or decarboxylation of oxygenated compounds, all these reactions involving protonic sites.     

Change in the decomposition mode of 1-propanamine due to the presence of cations in MFI zeolite

The adsorption and thermal analysis of 1-propanamine has been compared over MFI zeolites which contain H, Ga, and In cations. In the case of H⁺-containing materials, NH₃ and propene are simultaneously desorbed above 600 K. This behavior, is well known and characteristic of the Hofmann elimination reaction. However, a distinctly different mode of reaction is observed in the case of Ga and In containing materials. NH₃ is released below 600 K, propene and other products are released above 600 K, and a stable residue remains above 800 K. It is suggested that such behavior results from Lewis acid interactions of Ga or In cations with propanamine.On leave from the Bulgarian Academy of Sciences, Institute of Organic Chemistry.     

The desorption of O2 during NO and N2O decomposition on Cu- and Fe-zeolites

The decomposition of NO and of N₂O over a CuZSM-5 zeolite and a Fe-mordenite, respectively, has been studied using tracer techniques. The results demonstrate the high mobility of the lattice oxygen ions in self-diffusion. They afford a possible explanation for the problem of how two extralattice oxygens located at positions remote from each other may combine to form the O₂ molecules which are spontaneously desorbed in these redox reactions. They show that a portion of the lattice oxygen mixes into the O₂ released on decomposition. The data also show that N¹⁸O and N₂ ¹⁸O undergo exchange with the catalyst oxygen under reaction conditions.On leave from Central Research Institute for Chemistry, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.     

Heterogeneous Enzyme Mimics Based on Zeolites and Layered Hydroxides

Careful combination of a metal compound,a ligand and an inorganic support material leads to supramolecular catalysts that mimic the structural, organizational and functional aspects of enzyme activity.After discussing essential features of metalloenzyme-catalyzed reactions and coordination chemistry in inorganic hosts, we present examples of supramolecular materials selected from our own work that eventually resulted in useful catalysts for organic transformations in the liquid phase.