Rhodium alloys cyanide

A platinum-rhodium alloy is used as a catalyst at 1100°C. Approximately equal amounts of ammonia and methane with 75 vol% air are introduced to the preheated reactor. The catalyst has several layers of wire gauze with a special mesh size (approximately 100 mesh). The Degussa process, on the other hand, reacts ammonia with methane in the absence of air using a platinum aluminum-ruthenium alloy as a catalyst at approximately 1200°C. The reaction produces hydrogen cyanide and hydrogen, and the yield is over 90%. The reaction is endothermic and requires 251 kJ/mol. 

Platinum/rhodium alloy gauze is used as a catalyst in the selective oxidation of ammonia during nitric acid production and in the production of hydrogen cyanide. The wire in the gauze is only a few thousandths of an inch in diameter woven at 80 wires per inch. Several layers of gauze, up to about 8 ft in diameter, are used. 

Metal wires and screens are used as fixed-bed catalysts in which reactants are passed through the openings in the gauze, the size of which is defined by the mesh and wire diameter (see Fig. 10A). Gauzes composed of an alloy of platinum and rhodium catalyze the air oxidation of ammonia to nitric oxide, which is subsequently converted to nitric acid, and the production of hydrogen cyanide from ammonia, air, and methane. Formaldehyde production by... 

Nickel and iron salts. Attacks by aqua regia, fused nitrates, cyanides, chlorides at >1000°C. Alloys with gold, silver, and other metals Fused samples contaminated with the metal rhodium to increase hardness. Platinum cmcibles for fusions and treatment with HF Ni and Fe crucibles used for peroxide fusions... 

Tips are normally made of thin metal wires (ca. 0.25 mm), such as tungsten, platinum, or alloys (such as platinum-iridium and platinum-rhodium). Gold and silver tips can also be useful in some systems. To obtain the desired high resolution of the STM. it is necessary to have a very sharp tip with which to acquire the images. Tips can be prepared electrocheinically by etching the metal in a convenient solution, such as potassium hydroxide for W or basic aqueous cyanide solution for Pt-Ir tips. They can also be... 

Common palladium alloys include Pd-Ag with 1-60% Pd this material is tarnish resistant at greater than 50% Pd. The alloys are attacked by HNO3 and cyanide but are resistant to HCl except in the presence of oxidizing agents Pd-Ag-Cu, Pd-Ag-Au, and Pd-Au alloys also show good corrosion resistance and Pd-Cu, Pd-Ni, and Pd-Ru alloys are harder than palladium. Rhodium and ruthenium are often used together with palladium as with... 

---