Uranium synthesis catalyst

Studies of the decomposition of methanol over various catalysts show that the same catalysts are active toward the decomposition reaction cat pressures of one atmosphere as are active toward the synthesis at the higher pressures. Indeed, to Patart is attributed the statement that the results from the work of Sabatier on the catalytic decomposition of methanol led directly to the use of certain of the methanol synthesis catalysts.188 144 Smith and Hawk 145 found that zinc oxide made by igniting die carbonate, mixtures of zinc and chromium oxides in the atomic proportions of 4 zinc to 1 chromium, mixtures of zinc and uranium oxides,... 

Ammonia synthesis catalysts of high activity, prepared from alkali metal, e.g., potassium, ferrocyanide with the addition of uranium, aluminum, and/or rare-earth metal. V. S. Badik, V. V. Dovgel, and A. N. Sergeeva. SU 357783 (1979). 

Molybdenum In its pure form, without additions, it is the most efficient catalyst of all the easily obtainable and reducible substances, and it is less easily poisoned than iron. It catalyzes in another way than iron, insofar as it forms analytically easily detectable amounts of metal nitrides (about 9% nitrogen content) during its catalytic action, whereas iron does not form, under synthesis conditions, analytically detectable quantities of a nitride. In this respect, molybdenum resembles tungsten, manganese and uranium which all form nitrides during their operation, as ammonia catalysts. Molybdenum is clearly promoted by nickel, cobalt and iron, but not by oxides such as alumina. Alkali metals can act favorably on molybdenum, but oxides of the alkali metals are harmful. Efficiency, as pure molybdenum, 1.5%, promoted up to 4% ammonia. 

The uranium-antimony oxide system remains as a basis of interest for catalysts. The preparation of a new uranyl antimonate has been described and it was prepared by hydrothermal synthesis from UO3, SbsOs and KCl [46]. A detailed structural analysis was reported, but more importantly the U0sSb204 was selective for the oxidation of propylene to acrolein. 

On 2 July 1909 two representatives of BASF visited Haber s laboratory at Karlsruhe. Their brief was to evaluate Haber s apparatus for the high pressure synthesis of ammonia from its elements. Even under optimum conditions the yield was low, around 5 per cent, but Haber had arranged for unreacted hydrogen and nitrogen to be recirculated. Though exothermic, the reaction was carried out at 600°C in order to increase the rate. The preferred catalyst was osmium or uranium. 

The Haber-Bosch catalytic process for production of ammonia is perhaps an invention that had the most dramatic impact on the human race (Ritter 2008). The inexpensive iron-based catalyst for ammonia synthesis, which replaced the original, more expensive osmium and uranium catalysts, made it possible to produce ammonia in a substantially effective manner. The objective here was not improvement in selectivity but higher reaction rates for rapid approach to the equilibrium conversion at the specified temperatme and pressme. Higher rates meant lower catalyst volume and smaller high-pressme reactors. The iron catalyst was improved by addition of several promoters such as alkali metals. In contrast to this simple single reaction case of ammonia synthesis, most organic reactions are complex with multiple pathways. 

Efficient methods for the synthesis of nitriles by dehydration of aldoximes and primary amides have been developed. " The reactions were performed in the presence of a Lewis acid ionic liquid, a uranium, or a copper catalyst. 

The outstanding physical properties of the lanthanide-derived products as synthetic rubber (24, 27) related to their very high cis content, and some advantages or simplification in the polymer synthesis (25, 28) are the likely reasons for the widespread interest in lanthanide-catalyzed processes. Studies on cis-polydiolefins have been carried out by us over many years. After the early activity on uranium catalysts (29), we devoted our attention to lanthanides since 1974 with the aim of improving the synthesis and of understanding the related chemistry. 

Heat exchange, catalyst cooler Phthalic anhydride synthesis Uranium processing Coal combustion... 

However, osmium is a very rare resource and osmium oxide volatilize easily. Therefore, it was necessary to develop cheaper catalysts with excellent performances for ammonia synthesis. Since then, Haber identified that uranium is active for ammonia synthesis. However, in 1912, he was appointed as the director of Institute of Physical Chemistry and Electrochemistry in the Kaiser Wilhelm Institute, indicating the end of the research activity of Haber in the field of ammonia synthesis. Since then, Bosch and Mittasch became the principal researchers in BASF to continue the industrialization process for the ammonia synthesis. Bosch was the leader of the whole research group, and Mittasch became the main investigator for the exploration of catalysts. 

In the first instance, substantially better catalysts were required for the synthesis stage. As mentioned above, active and stable catalysts allow the synthesis reaction to take place at lower pressures and temperatures. It was, accordingly, of fundamental importance to discover good catalysts which were cheaper and more stable than osmium and uranium, since both were difficult to obtain and presented handling problems. 

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