| Abstrakt: |
Day by day more restrictive regulations concerning environment protection induce progress in the technology of chemical processes. This is why there is a growing interest in the field of catalysis, which is probably one of the greatest contributions of chemistry or chemical technology to both economic growth and environmental protection. The area of molecular sieves has been developed in the last decades into an impressive group of inorganic-hybrid materials with a vast number of industrial applications, particularly in the field of catalysis. They include zeolites, mesoporous materials and metal-organic frameworks (MOFs). In particular, zeolites are crystalline aluminosilicates formed by nanocavities and channels of strictly regular dimensions. They are of different sizes and shapes. Especially the three-dimensional large internal pore (∼13 Å) zeolite-Y, which has been studied here as host lattices. Entrapment of transition metal complexes in the supercages of zeolite-Y seems to be a good method to satisfy environmental demands and to obtain catalysts which preserve the properties of homogeneous systems. The as-prepared inorganic-hybrid material not only has heterogeneous catalysis characteristics, but also retains high catalytic efficiency originating in homogeneous catalysis due to the "site isolated effect." For a better tomorrow, the development of environmentally benign catalysts is a challenge in front of scientists. The catalyst should be easily separable, inexpensive, noncorrosive, recyclable, and also the metal ion leaching from the catalyst should be nil. To achieve the above-mentioned goal, in this chapter we report on zeolite-Y enslaved nanohybrid materials as eco-friendly catalysts over liquid-phase hydroxylation of phenol and oxidation of cyclohexane using 30% H2O2 as an oxidant. The effi ciency of these catalysts has been studied using optimized reaction conditions such as the effect of reaction time, effect of solvent, effect of amount of catalyst and effect of temperature to get utmost yield. No considerable decreases in the effi ciency of the catalysts were observed after two cycles of operation. [ABSTRACT FROM AUTHOR] |
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