Catalyst components identification

Identification of catalyst components in terms of active phase or active sites and search for correlations between these components and one or more of the catalytic properties. 

Some differences between the features of the almnina supported catalyst and the filter supported catalyst were found comparing the results of X-ray diffraction (XRD) analysis performed on both catalysts. The XRD spectmm of the catalytic filter shows a greater number of signals with respect to the catalyst 137AA. Due to the complexity of the interaction between the catalyst components and the support, the identification of such signals is difficult and is still object of study. Furthermore, it is important to remark the absence in the catalytic filter spectrum of the signals due to KCl that are, instead, characteristic of the catalyst 137AA [19]. 

There will now be presented some examples of the use of these data for the identification of catalyst components. It will be clear that the method is by no means limited to substances of interest in catalysis but could have useful application in mineralogy, ceramics, metallurgy, and related fields. 

One of the most recent design approaches for the identification of effective partial oxidation catalysts has considered the activation of reactant and product molecules with catalytically active metal oxide materials (442,443). It is clear that the most effective selective oxidation catalysts are based on metal oxide systems, and it is by this precedent that the activation of methane, oxygen, and methanol has been examined on single metal oxides. The aim of the approach is to search for reactivity factors for catalyst components that when combined in two-component metal oxide catalysts will lead to catalyst formulations with a high degree of synergy for selective methane oxidation. The approach involves the identification of components that... 

Mossbauer technique is effective for the identification of catalyst components in terms of active phase or active sites and search for correlations between these components and one or more of the catalytic properties [15,17-23]. Here, Fe Mossbauer spectroscopy was employed to characterize the iron state in the as-prepared materials. Fig. 29.1 shows... 

Polyester composition can be determined by hydrolytic depolymerization followed by gas chromatography (28) to analyze for monomers, comonomers, oligomers, and other components including side-reaction products (ie, DEG, vinyl groups, aldehydes), plasticizers, and finishes. Mass spectroscopy and infrared spectroscopy can provide valuable composition information, including end group analysis (47,101,102). X-ray fluorescence is commonly used to determine metals content of polymers, from sources including catalysts, delusterants, or tracer materials added for fiber identification purposes (28,102,103). 

Antimony trichloride is used as a catalyst or as a component of catalysts to effect polymerisation of hydrocarbons and to chlorinate olefins. It is also used in hydrocracking of coal (qv) and heavy hydrocarbons (qv), as an analytic reagent for chloral, aromatic hydrocarbons, and vitamin A, and in the microscopic identification of dmgs. Liquid SbCl is used as a nonaqueous solvent. 

Bosch and co-workers devised laboratory reactors to operate at high pressure and temperature in a recycle mode. These test reactors had the essential characteristics of potential industrial reactors and were used by Mittasch and co-workers to screen some 20,000 samples as candidate catalysts. The results led to the identification of an iron-containing mineral that is similar to today s industrial catalysts. The researchers recognized the need for porous catalytic materials and materials with more than one component, today identified as the support, the catalyticaHy active component, and the promoter. Today s technology for catalyst testing has become more efficient because much of the test equipment is automated, and the analysis of products and catalysts is much faster and more accurate. 

A family of 100 hybridoma antibodies can typically provide 20 tight binders and these need to be assayed for catalysis. At this stage in the production of an abzyme, the benefit of a sensitive, direct screen for product formation comes into its own. Following identification of a successful catalyst, the antibody is usually recloned to ensure purity and stabilization of the clone, then protein is produced in larger amount (—10 mg) and used for determination of the kinetics and mechanism of the catalysed process by classical biochemistry. Digestion of such protein with trypsin or papain provides fragment antibodies, Fabs, that contain only the attenuated upper limbs of the intact IgG (Fig. 1). It is these components that have been crystallized, in some... 

Electron microscopic examination of catalyst materials, particularly those containing natural components, permits the identification of their origin. For example, carbons utilized as supports for precious metals in a wide variety of slurry-phase and fixed-bed reactions can be derived from a large number of naturally occurring sources (Fig. 8). The shape, morphology, and composition are useful properties for determining their origin. 

Some general applications of TG-FTIR are evolved gas analysis, identification of polymeric materials, additive analysis, determination of residual solvents, degradation of polymers, sulphur components from oil shale and rubber, contaminants in catalysts, hydrocarbons in source rock, nitrogen species from waste oil, aldehydes in wood and lignins, nicotine in tobacco and related products, moisture in pharmaceuticals, characterisation of minerals and coal, determination of kinetic parameters and solid fuel analysis. 

The conversion of chloromethane over ZSM-5 to gasoline-range hydrocarbons occurred under conditions comparable to those for the conversion of methanol. The reaction was typically conducted at constant temperature, whereas conversions and product distributions were determined as functions of space velocity or catalyst time-on-stream. The mass-selective detector allowed identification of most of the components in the liquid samples. Generally, the products contain ten carbons or less, and a large fraction of the products are aromatic. The ZSM-5 catalyst was stable under extended exposure to chloromethanes. Figure 2 illustrates the catalyst activity after nearly 700 hours of exposure to chloromethane, during which time the catalyst had been oxidatively regenerated to remove coke that had been deposited on the catalyst. 

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