New methods of zeolite synthesis

03-K-01 - Application of combinatorial tools to the discovery and commercialization of microporous solids facts and Action 

Holmgren, D. Bern, M. Bricker, R. Gillespie, G. Lewis, D. Akporiaye, I. Dahl, A. Karlsson, M. Plassen and R.Wendelbo  

During the past three years, combinatorial tools and methods have received increasing amounts of attention as potentially enabling methodologies for the chemical industry. We have developed an integrated End-to-End combinatorial catalyst discovery system, which allows us to perform all the critical catalyst processing operations combinatorially. A critical component of this system is a combinatorial multiautoclave assembly, which can be used to explore hydrothermal space efficiently and effectively. Our recent results illustrate the applicability of this capability to both the discovery and scale-up of microporous solids. The expected impact of these combinatorial tools in new product commercialization and the chemical industry will be discussed. 

03-0-03 - Synthesis of novel zeolites SSZ-53 and SSZ-55 using organic templating agents derived from nitriles 

Chevron Research Tech. Co., elom chevron.com, Richmond94802 CA. USA 

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A. P. Rauter, F. Ramoa-Ribeiro, A. C. Fernandes, and J. A. Figueiredo, A new method of acetonation with the zeolite HY as catalyst. Synthesis of O-isopro-pylidene sugar derivatives, Tetrahedron, 51 (1995) 6529-6540. 

Post-synthesis methods (pore-size engineering) allow an existing shape-selectivity effect to be intensified, and also a new one to be established. However, normally not only the pore size will be influenced by most of these methods, but also the catalytic activity. Vansant [104] gives a classification of post-synthesis modification methods which covers the entire range of zeolite applications (gas separation, gas purification, encapsulation of gases and catalysis). 

Ion exchange methods and direct synthesis techniques can be used to incorporate Co ions into ZSM5 zeolites at well defined positions. The solid state ion exchange led to the formation of two new (Lewis acid) sites. One was affiliated with the presence of Co cations equimolar exchanged with the protons of SiOHAl groups. The other site, which revealed a very strong Lewis acid character, was associated with the presence of (CoCl) and (CoOH) species. 

F was used for the first time as mineralizer in the synthesis of zeolites under neutral or acidic conditions by Flanigen and Patton1941 Subsequently, Guth and Kessler further studied this new synthetic method.[95] Many high- or all-silica zeolites such as ZSM-5, ZSM-23, Theta-1, ferrierite, / , MTN, AST, UTD-1, ITQ-3, ITQ-4, and heteroatom (B, Al, Fe, Ga, and Ti)-substituted high-silica zeolites could be synthesized from an F synthetic system. In addition, most of the open-framework gallophosphates could be hydrothermally synthesized under the influence of F. ... 

The modification of zeolites mainly relies on secondary synthesis methods. The aim of modification is to reprocess the zeolites using suitable techniques to improve the properties and functions such as (1) acidity, (2) thermal and hydrothermal stability, (3) catalytic performance such as redox catalytic and coordination catalytic properties, etc., (4) channel structures, (5) surface properties and microporous frameworks and charge-balancing ions. Modification is also called secondary synthesis and can lead to new properties that cannot be achieved through direct synthesis. Let us consider the case of faujasite (FAU), the main component of the cracking catalyst, and its catalytic performance (represented by the catalytic activity K/K Std for n-hexane cracking). From Table 6.1 it is seen that the secondary synthesis affects the catalytic performance to a considerable degree. 

Combinatorial chemistry is the production of libraries of compounds that represent permutations of a set of chemical or physical variables. In recent years, combinatorial chemistry has attracted considerable attention in materials science.11131 Originating from the discovery of new chugs by pharmaceutical companies, combinatorial methods have been employed in the areas of organic, biochemical, and inorganic chemistry, etc. In recent years, the combinatorial approach has been successfully applied to the hydro-thermal synthesis of zeolites and related materials.11141... 

New methods are focused on the preparation of solid catalysts without release of gaseous or liquid waste streams. In zeolite synthesis, the chemical compounds generated during combustion of templates (structure-directing agent) are often hazardous and harmful to the environment. A new method teaches disassembling the template within zeolite pore space into small fragments without combustion. ... 

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