Fischer spectroscopic studies

There exists also a discrepancy in the data obtained for the sensitized photolysis of azo benzene. The different results of Jones and Hammond 28> for direct and sensitized photolysis most probably imply a %E7z -state in the sensitized and a singlet state in the direct photolysis. However the findings of Fischer 24,47) as well as theoretical calculations 114 and spectroscopic studies 51>, again suggest a triplet state. 

Fischer et al. [101] investigated the simultaneous quantification of the content of several additives in PVC with an in-line diffuse reflectance probe. The signal from diffuse reflectance can be affected by a number of physical properties of the sample, rather than just its chemical make up. This makes obtaining quantitative data very difficult. Chemometric analysis showed the possibility of detecting even small amounts of additives (3%) with an absolute prediction error of 0.3%. Step-scan PA-FTIR spectroscopic studies were used to study surfactant exudation and film formation in PS-nBA latex films [102]. 

Li, S., Ding, W., Meitzner, G.D., and Iglesia, E. 2002. Spectroscopic and transient kinetic studies of site requirements in iron-catalyzed Fischer-Tropsch synthesis. J. Phys. Chem. B 106 85-91. 

Cobalt-based Fischer-Tropsch catalysts are the subject of continuing interest as large-scale Gas-to-Liquids plants come on line. Fernando Morales and Bert Weckhuysen (Utrecht University, the Netherlands) look specifically at the effects of various promoters for these catalysts, particularly Mn. The effect of these promoters in controlling the activity and selectivity of the overall reaction can be critical in the overall process economics. This chapter also looks at new spectroscopic techniques that have recently been used to study the effects of these promoters. 

Another technologically important reaction is the Fischer-Tropsch synthesis, with iron oxide being one of the components of some catalysts. A detailed understanding of the complex mechanism of this reaction can be obtained by studying the chemisorption of simple molecules on well-characterized surfaces by means of advanced surface-sensitive spectroscopic techniques. A few investigations of the interaction of small molecules (such as CO, CO2, H2O, O2, H2, and NO) (520-522) and organic molecules on iron oxide surfaces (523-527) have been carried out. 

The electron microscope offers a unique approach for measuring individual nano-sized volumes which may be catalytically active as opposed to the averaging method employed by spectroscopic techniques. It is just this ability of being able to observe and measure directly small crystallites or nano-volumes of a catalyst support that sets the microscope apart from other analyses. There have been many studies reported in the literature over the past fifteen years which emphasize the use of analytical and transmission electron microscopy in the characterization of catalysts. Reviews (1-5) of these studies emphasize the relationship between the structure of the site and catalytic activity and selectivity. Most commercial catalysts do not readily permit such clear distinction of physical properties with performance. The importance of establishing the proximity of elements, elemental distribution and component particle size is often overlooked as vital information in the design and evaluation of catalysts. For example, this interactive approach was successfully used in the development of a Fischer-Tropsch catalyst (6). Although some measurements on commercial catalysts can be made routinely with a STEM, there are complex catalysts which require... 

Menzel, H., Hallensleben, M. L., Schmidt, A., Knoll, W., Fischer T., and Stumpe, J. Langmuir-Blodgett-Films of Photochromic Polyglutamates IV. Spectroscopic and Structural Studies on LB-Films of Copolyglutamates Bearing Azobenzene Moieties and Long Alkyl Chains. Macromolecules 26, 3644 (1993). 

For use as solvent in a kinetic study (Olah ), Eastman spectroscopic grade nitromethane was washed three times with a solution containing 25 g. of NaHCOa and 25 g. of NaHSOs per liter, then with water, 5% sulfuric acid, water, aqueous NaHCOs, dried overnight with Drierite, then passed through a 2-ft. column of A in. type 4A Linde molecular sieves, and distilled at 58°/160 mm. from a small amount of sieve powder to yield solvent neutral to bromphenol blue in ethanol and dry to Karl Fischer reagent ( D 1.3790). 

Holmes, E. Bonner, F.W. Nicholson, J.K. H NMR Spectroscopic and Histopathological Studies on Propyleneimine-induced Renal Papillary Necrosis in the Fischer 344 rat and the Multimammate Desert Mouse (Mastomys natalen-sis). Compar. Biochem. Pharmacol. (C) 116(2), 125-134 (1997). 

With Thompson and Irsa the study of the Fischer Tropsch synthesis using deuterium gas,(89,90) with Lewis Friedman on reduction of acetone,(91,92) with G. C. Bond, the reaction of propylene(93) and cyclopropane(94) with deuterium. Using the ethylene-deuterium reaction as an example,(98) the mass spectroscopic approach permitted analysis of each of the five ethylenes and seven ethanes at the same time and showed, among other interesting data, that the first product of the reaction between deuterium and ethylene was an ethane containing no deuterium. 

Cobalt-containing alumina supported catalysts modified by a second metal have been parallel tested in the Fischer-Tropsch synthesis under pilot conditions. It has been observed that promotion of alumina supported Cocontaining catalysts by certain amounts of Pt leads to an increase in the formation of high molecular-weight hard hydrocarbons, so-called ceresins (77%). Also, it has been found that ceresin formation is strongly dependent on process conditions (pressure, temperature and space velocity). By parallel testing, the catalyst composition and process conditions for the selective production of ceresins from synthesis-gas have been determined and optimised. The physico-chemical properties have been studied by X-Ray, TEM, IR-spectroscopic, TPR and other methods. The synthesised catalysts are highly effective and stable. 

Arenes form ir-complexes with all the transition metals. Many ir-arene complexes have been isolated, structurally characterized, and studied by a plethora of spectroscopic techniques. The first T -arene complexes were prepared by Hein in 1919, but the structures of these compoimds were not fully recognized until 1954. The prototype "sandwich" complex, bis(benzene)chromium, Cr(CjH )2, was prepared by E. 0. Fischer in 1955. ... 

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