Platinum-magnesium catalyst

The parent system 3 was reported fw the first time as a product obtained in low yield originating from the vapor-phase cyclodehydrogenaticMi of /V,/V -diphenyl-m-phenylenediamine (137) over a platinum-on-magnesium catalyst (Scheme 17) (61JOC1509). 

As shown in the following method of preparing platinum hydroxide on magnesium oxide, hydrolysis of platinum(u) chloride by carrier magnesium oxide, may yield a platinum oxide catalyst 145... 

The olefin is added, when possible without a catalyst (BF3), to liquid HF cooled to —40 to —60° the mixture is allowed to warm gradually and finally kept at 75-90° for 1-2 h. The reaction vessel may be made of copper, Monel metal, stainless steel, platinum, magnesium, or nickel. Reactions giving low-boiling fluorides must be carried out in an autoclave. No addition can be achieved when concentrated aqueous HF is used. 

Salts of neodecanoic acid have been used in the preparation of supported catalysts, such as silver neodecanoate for the preparation of ethylene oxide catalysts (119), and the nickel soap in the preparation of a hydrogenation catalyst (120). Metal neodecanoates, such as magnesium, lead, calcium, and zinc, are used to improve the adherence of plasticized poly(vinyl butyral) sheet to safety glass in car windshields (121). Platinum complexes using neodecanoic acid have been studied for antitumor activity (122). Neodecanoic acid and its esters are used in cosmetics as emoUients, emulsifiers, and solubilizers (77,123,124). Zinc or copper salts of neoacids are used as preservatives for wood (125). 

Figure 7 compares in function of time the activities of catalyst B and platinum supported on magnesium oxide MgO, a well-known basic industrial catalyst. 

Schroder-Grillo Also known as Grillo-Schroder. An early version of the contact process for making sulfuric acid. The catalyst was magnesium sulfate impregnated with platinum. The process was invented in 1899 by A. Hecksher at the New Jersey Zinc Company and first used at its plant in Mineral Point, WI, in 1901 this was the first use of the contact process in the United States. In the United Kingdom it was first used in Widnes in 1917. See also Mannheim (2). 

Although the forward reaction is favored by increase in pressure, this is not employed in practice since 97 to 99% conversion of sulfur dioxide to sulfur trioxide can be accomplished at the temperature specified here, provided suitable catalysts are used. The first catalyst used for this reaction consisted of finely divided platinum dispersed in asbestos, anhydrous magnesium sulfate, or silica gel. Other catalysts were later discovered. Mixtures of ferric and cupric oxides are useful, but these are less efficient than platinum. Certain mixtures containing vanadium pentoxide (V205) and other compounds of vanadium appear to be as good as or better than platinum. There has been much controversy over the relative merits of platinum and vanadium catalysts, and only time will provide the answer as to which is best. 

PDH [Propane DeHydrogenation] A catalytic process for converting propane to propylene. The catalyst was originally chromium on alumina, but is now platinum on magnesium aluminate. Developed by a consortium of Linde, BASF, and Statoil. 

In general, the catalysts contain varying quantities of the oxides of aluminum, potassium, calcium, magnesium, and silicon as promoters. Patents recommend adding sodium [243], beryllium [244], vanadium [245], uranium [246], or platinum [247]. Reference [248] describes cesium-containing catalysts. Catalysts patented by Lummus [249] and Ammonia Casale [250] contain cerium as additional promoter. ICI [251] has developed a cobalt-containing catalyst, as has Grande Paroisse [252]. 

---