Multifunctional catalytic

The future will undoubtedly show considerable activity in the field of (metal-lo)dendrimers, not only because of the beauty of the structures and the synthetic challenge their preparation involves, but also because of their usefulness in fundamental applications and applied science. Finally, while we are learning to design, synthesize and apply these multimetallic catalytic objects (either soluble or insoluble), other challenges may include preparation of multifunctional catalytic prototypes by including, e.g. a substrate recognition function next to the catalytically active site. 

A. first-of-a-kind multifunctional catalytic system is being developed to convert synthesis gas into synthetic crude via the Fischer-Tropsch reaction. This is achieved through intensification of chemical reaction and heat and mass transport processes within the catalyst system. Tbe synergistic integration of intensified unit operations with chemical reaction leads to enhanced catalyst performance and significant economic advantages. 

Despite widespread commercial use and considerable research efforts, the vanadium-phosphorus oxide multifunctional catalytic system remains poorly understood It is generally accepted that (V0)2P2O7 bulk phase is the most selective one to produce maleic anhydride (MA) from n-butane [1], However, in spite of the large number of studies on the VPO catalysts there are stiU many unclear things and disagreements in scientific hterature. The catalyst surface composition and structure under reaction conditions are difficult to stu and stiU remains unresolved... 

In the following, such a desired new and innovative multifunctional catalytic system is reviewed The chiral heterobimetallic lanthanoid complexes, developed by Shibasaki et ah, have recently been shown to catalyze a broad spectra of organic reactions including many classical carbon-carbon bond formations... 

Geilen FMA, Engendahl B, Harwardt A, Marquardt W, Klankermayer J, Leitner W (2010) Selective and flexible transformation of biomass-derived platform chemicals by a multifunctional catalytic system. Angew Chem Int Ed 49 5510-5514... 

Kingsbury, B.F.K. (2010) A morphological study of ceramic hollow fibre membranes a perspective on multifunctional catalytic membrane reactors, Imperial College London PhD thesis. 

Often multicomponent catalyst systems are utilized to carry out reactions consisting of two or more active metal components or both oxide and metal constituents. For example, a Pt-Rh catalyst facilitates the removal of pollutants from car exhausts. Platinum is very effective for oxidizing unburned hydrocarbons and CO to H2O and CO2, and rhodium is very efficient in reducing NO to N2, even in the same oxidizing environment. Dual functional or multifunctional catalysts are frequently used to carry out complex chemical reactions. In this circumstance the various catalyst components should not be thought of as additives, since they are independently responsible for different catalytic activity. Often there are synergistic effects, however, whereby the various components beneficially influence each other s catalytic activity to provide a combined additive and multifunctional catalytic effects. 

Halloin VL, Wajc SJ. A multifunctional catalytic reactor suitable for the exothermal synthesis of condensable products. Chemical Engineering Science 1994 49 4691-4698. 

After a thorough revision of the examples found in the literature, the benefits of encapsulation of active species in MOFs mainly consist in (1) inaeased stability and prevention of self-deactivation/aggregation of the encapsulated species, (2) development of shape-selective properties upon encapsulation, and (3) possibility of designing multifunctional catalytic systems. 

A promising alternative to reduce soot emission is the development of a multifunctional catalytic filter that combines filtration and oxidation of the emitted particulate matter. Consequently, several authors have carried out studies of catalysts such as perovskite (La-Li-Cr or lanthanum cobaltite)-t)q)e oxides in a temperature-programmed combustion microreactor (>600 °C) offering the best compromise between satisfactory catalytic activity and stability [17,18]. 

A variety of catalytic routes have been described in recent years for the chemical transformation of carbohydrates into hydrocarbon liquid fuels and oxygenated biofuels which wiU be discussed in this chapter. Special focus will be brought to the recent progress of integrated processes based on the use of multifunctional catalytic systems without isolation of the platform intermediates. Fig. 13.1 summarizes the main chemical routes for the conversion of cellulosic platform molecules into high-energy-density biofuels. 

Salen Manganese Complexes Multifunctional Catalytic Antioxidants Protective in Models for NeurodegeneratiVe Diseases of Aging... 

FIG U RE 11.1 Progression of ceramic membrane technology from its inception in the 1940s to the present day. (Data from B.RK. Kingsbury, A morphological study of ceramic hollow fibre membranes A perspective on multifunctional catalytic membrane reactors, PhD Thesis, Imperial College London, London, 2010.)... 

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