Experiments with iron

Two unrelated discoveries of vanadium seem to have occurred. When he was experimenting with iron in 1830, Nils Gabriel Sefstrom (1787—1845), a Swedish chemist and mineralogist, identified a small amount of a new metal. Because vanadium compounds have beautiful colors, he named this new metal after Vanadis, the mythological goddess of youth and beauty in his native country, Scandinavia. 

In the original derivation of (305), it was supposed (40) that the nitrogen adsorption equilibrium on the catalyst follows the logarithmic isotherms (i.e., that the surface is evenly nonuniform). In this case y — 0 and, according to (143) and (164), m — a, n — / . Experiments with iron catalyst promoted with A1203 and K20 gave m = 0.5. This was interpreted as a = 0.5 (93). 

Ibanez, J. G. Miranda, C. Topete, J. Garcia, E. Metal Complexes and the Environment Microscale Experiments with Iron-EDTA Chelates, Chem. Educ. 2000, 5, 226-230. http //joumals.springemy.com/chedr/... 

The catalytic activity of iron was already known well before the advent of industrial ammonia synthesis. Ramsay and Young used metallic iron for decomposing ammonia. Perman [236], as well as Haber and Oordt [237], conducted the first catalytic synthesis experiments with iron at atmospheric pressure. Nernst [12] used elevated pressures of 5-7 MPa. Pure iron showed noticeable initial activity which, however, could be maintained for longer operating periods only with extremely pure synthesis gas. 

Tracer Experiments— Fe, Zn, Cd, Ni, Cu, and Mn. The success of the method for copper and lead suggested an extension to other metals. Preliminary experiments with iron, zinc, and cadmium showed poor reproducibility. In order to establish conditions suitable for the determination of these elements, experiments using radioactive tracers were done inthe laboratory of M. P. Bender at the University of Rhode Island. The method was adapted to these experiments as follows ... 

Fischer s experiments with iron catalysts promoted with alkalies showed that they increased in efficiency with the strength of the base, with the exception of caesium. Working with catalysts prepared by calcining steel turnings with potassium hydroxide, Frolich and Lewis 1J7 showed that with a gas containing 40 per cent carbon monoxide passed into the reactor at a space velocity of 1250 at 200 atmospheres and 325° to 335° C. the best yields were obtained when the base comprised 2.2 per cent of the catalysts (calculated as K20). From this it appears that a strong base present in small amount with iron as the catalyst enables the best yields of liquid products to be obtained. This conclusion has been confirmed by the work of Audibert and Raineau. 

Schwarzheide—Experiments with Iron Catalysts (Comparison of... 

Basic research work. In connection with an exhaustive research program, Fischer, Tropsch, and Ter Nedden (8) also carried out some experiments with iron catalysts at a pressure of 10-15 atm. (250-280°C.). They obtained aqueous reaction products and nonaqueous oil in the ratio 3 1 to 1 1, and paraffins with melting points up to 117°C. However, the catalysts used at that time were not suitable for the production of hydrocarbons at increased pressures. The comparatively low activity of the catalysts declined very rapidly as the result of the adsorption of high melting waxes and possibly also of oxygenated products. Tropsch (9) stated If the process is to be carried out at increased pressures, it is necessary to increase the temperature in order to make it possible that the reaction products leave the catalyst. In this case the reaction products are oxygenated products, probably formed by a secondary reaction. ... 

Meyer and Bahr (21) carried out similar experiments with iron-kiesel-guhr catalysts. The type of catalyst support, which was very important in the case of cobalt and nickel catalysts, showed no pronounced influence in the case of iron catalysts. Iron catalysts produced from ferro salts and kieselguhr were not active, while iron catalysts produced from ferri salts and kieselguhr yielded comparatively good results. 

Schwarzheide—experiments with iron catalysts (comparison of different precipitation catalysts with a Nil 3 type fused iron catalyst). In view of the favorable results obtained by the Coal Research Institute in Miilheim (Fischer Pichler, 1937), industrial companies started experiments on medium-pressure synthesis with iron catalysts. 

An interesting observation made by Kolbel and Ackerman (44) in connection with experiments with iron catalysts suspended in high-boiling synthetic oil fractions was that the oil participates in the synthesis of high molecular hydrocarbons. 

Kolbel and Ackermann report on the basis of synthesis experiments with iron catalysts suspended in hydrogenated synthetic oil, not only a catalytic cracking of the oil, but also participation of the oil in the conversion of carbon monoxide and hydrogen, resulting higher molecular hydrocarbons (44). 

Weller (133) passed carbon monoxide over a cobalt catalyst at synthesis conditions and found high carbon monoxide consumption during the very first moment of the treatment. The carbon monoxide consumption diminished rapidly to a much lower but steady rate. Evidently a flash carbiding of the surface occurred, followed by a slower reaction of the bulk metal. The rate of synthesis is comparable with the initial carbiding rate. Hydrogenation of the cobalt carbide proceeds faster than the carbiding (in contrast to the experiences with iron catalysts). 

In spite of the shortcomings of the simple picture developed through earlier work, the assumption that adsorbed alcohols are intermediates in the Fischer-Tropsch synthesis does explain many of the features of the tracer experiments with iron catalysts. 

This report is remarkable in that only 17% methane plus ethane is specified. Others who have experimented with iron catalysts at 300-320°C., with little or no recycle of end gases, have reported much higher yields of methane ai d ethane. The cost of operation of this process is markedly dependent upon the pressure drop across the catalyst bed. This was reported to be 1 meter water/meter of catalyst depth. Increased gradients would result with increasing carbon deposition, and the operating temperature is dangerously close to that at which a rapid rate of carbon formation occurs. 

Fig. 1.9 The sites of LOHAFEX and former ocean fertilizing experiments with iron salts. (Authors own work and copyright-free Wikipedia picture)...

Although phlogiston for Watt could mean hydrogen, it could also mean any kind of inflammable air, including carbon monoxide, as it did for Priestley, whereas Cavendish had clearly stated that the gas from charcoal is a different kind of inflammable air from that (hydrogen) which he used, and he had also disproved Priestley s conclusion from the experiment with iron filings and red precipitate. If the most favourable interpretation is given to Watt s statements, he believed that ... 

Electrochemical dissolution of sacrificial anodes, for example, iron, aluminum, or magnesium, has been proposed for phosphate removal from urine. Ikematsu et al. [15] used an electrochemical reactor craisisting of two DSA and one iron electrode for combined nitrogen oxidation and phosphate precipitatirai. First, urea was oxidized at the DSA, then the current direction was changed, and phosphate was precipitated by dissolving the iron electrode. Zheng et al. [29, 30] used synthetic and real fresh urine for their experiments with iron and aluminum electrodes. With both types of electrodes, complete phosphate removal was achieved. At 40 mA cm and a gap width of 5 mm, 1.3 mol Fe. mol had to be dosed to remove 98 % of the phosphate (calculated by assuming a current efficiency... 

S. Tauster, Poisoning Experiment with Iron-Type Ammonia Synthesis Catalysts, Doctoral Thesis, Polytechnic Institute of Brooklyn, June 1964 (available university microfilms, 64-10, 728). 

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