Iridium-alumina catalysts reactions over

The dehydrocyclization activity of rhodium-alumina is lower than that of platinum-alumina. Hydrogenolysis predominates over all the other reactions with this catalyst (57). The effect of temperature on the anthracene/phenanthrene ratio in the product from 2- -butylnaphthalene is the same over iridium-alumina catalyst as that observed over platinum-alumina more phenanthrene and less anthracene are formed at high temperatures (58). 

The use of the ethane hydrogenolysis reaction as a chemical probe in the characterization of platinum-iridium on alumina catalysts is illustrated by the data in Figure 4.21. Rates of hydrogenolysis per iridium atom are shown over a range of temperatures for a series of catalysts containing 0.3 wt% iridium... 

Hydrazine has been studied extensively for use in monopropellant thrusters for space flights of long duration. Thrusters are used or altitude control of communication satellites. Here the decomposition of hydrazine over a packed bed of alumina-supported iridium catalyst is of interest. " In a proposed study, a 2% hydrazine in 98% helium mixture is to be passed over a packed bed of cylindrical particles 0.25 cm in diameter and 0.5 cm in length at a gas-phase velocity of 15m/s and a temperature of 750 K. The kinematic viscosity of helium at this temperature is 4.5 X 10 nF/s. The hydrazine decomposition reaction is believed to be externally mass transfer-limited under these conditions. If the packed bed is 0.05 m in length, what conversion can be expected Assume isothermal operation. 

Al-Ammar AS, Webb G (1978) Hydrogenation of acetylene over supported metal catalysts Part 1 - Adsorption of [ C] Acetylene and [ C] ethylene on silica supported rhodium, iridium and palladium and alumina supported palladium. J Chem Soc Earaday Trans 74 195 Al-Ammar AS, Webb G (1979) Hydrogenation of acetylene over supported metal catalysts Part 3 - [ C] tracer studies of the effect of added ethylene and carbon monoxide on the reaction catalyzed by silica-supported palladium, rhodium and iridium. J Chem Soc Faraday Trans 75 1900... 

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