Adya Jain* and Radha Tomar Pages 84 - 115 ( 32 )
Background: The principal goal of this review is to provide a detailed study of various modified zeolites as catalysts for the synthesis of diverse organic biologically active compounds. The use of zeolites in organic synthesis is noteworthy since they are compatible with the reactants, ecofriendly, non-toxic, non-corrosive, insoluble in many solvents, resistive at high temperatures, and reusable with high yield and purity.
Methods: Zeolites are three dimensional structures of crystalline, micro porous, hydrated aluminosilicates of alkali and alkaline earth metals. Primary building blocks of zeolites are the basic tetrahedral anions, i.e. [SiO4]4- and [AlO4]5-. Based on the Si/Al ratios, zeolites are classified into three major divisions and the composition ratios present in them can be altered. Molecules within the diverse zeolites cavities can be trapped because of their electrostatic and Vander walls types of attractive forces. Nanocrystalline zeolites have larger surface areas with internal surface porosity.
Results: As a result, an increase in the surface area of specific zeolites is possible and thus superior adsorption of reactant molecules on its surface may take place. The whole structural orientation results in characteristic catalytic property within the zeolite systems.
Conclusion: Greater catalytic activity is achieved with polyvalent ions rather than monovalent ions. Interestingly, the yield of drug intermediates depends on various parameters of catalysts (i.e. zeolite porosity, surface area, properties of doped metal ions/complexes, Si/Al ratio, number of Lewis and Bronsted acid sites, etc.). Medium and large pore containing zeolite gives a higher yield of products in comparison to zeolite that has a small pore. In addition, a zeolite with a higher surface area and higher Si/Al ratio exhibits higher catalytic efficiency.
Biological activity, catalyst, crystalline, nanocrystalline, pharmacologically active substances, zeolites.
School of Studies in Chemistry, Jiwaji University, Gwalior- 474011, MP, School of Studies in Chemistry, Jiwaji University, Gwalior- 474011, MP