Nickel/titania catalysts hydrogen

Takenaka ct al. studied the activity of various catalysts for carbon monoxide methanation in the absence of carbon dioxide [342]. From the different active species on a silica carrier, 5 wt.% ruthenium, 10wt% nickel and 10 wt.% cobalt were significantly more active than iron, palladium or platinum, each prepared with an active species content of 10 wt.%. Then Takenaka tested nickel, ruthenium and cobalt catalysts on different carrier materials, namely, alumina, silica, titania and zirconia. The formulations most active were nickel/zirconia and mthenium/ titania catalysts. The best performing catalyst was the 5 wt.% mthenium/titania, which converted the carbon monoxide apart from less than 20 ppm from a feed mixture containing 60 vol.% hydrogen, 15 vol.% carbon dioxide, 0.9 vol.% steam, 0.5 vol.% carbon monoxide, with a balance of helium at 220 °C. The space velocity was rather high at 300 L (hgcat) -... 

F-T Catalysts The patent literature is replete with recipes for the production of F-T catalysts, with most formulations being based on iron, cobalt, or ruthenium, typically with the addition of some pro-moter(s). Nickel is sometimes listed as a F-T catalyst, but nickel has too much hydrogenation activity and produces mainly methane. In practice, because of the cost of ruthenium, commercial plants use either cobalt-based or iron-based catalysts. Cobalt is usually deposited on a refractory oxide support, such as alumina, silica, titania, or zirconia. Iron is typically not supported and may be prepared by precipitation. 

Originally Bergius felt that coal hydrogenation could not be catalyzed because the large quantities of sulfur present would poison the catalysts. He added luxmasse simply to absorb sulfur from the products although, coincidentally, the combination of iron oxide with titania and alumina was an excellent choice of catalyst. Since his first tests, however, the industrial use of the process has depended on catalysts that were developed more or less empirically. It was soon realized that the processes involved in hydrogenating coal were more complex than the simple reactions described by Sabatier and Ipatieff. Different catalysts such as iron oxide or iron snlfide, probably with traces of other metal oxides, were reqnired. These catalysts could be used in the presence of snUhr and were, in fact, even more active when sulfided. Several studies reported that iron, nickel, cobalt, tin, zinc, and copper chlorides were effective catalysts and claimed that aimnoninm molybdate was particularly active. 

Adiponitrile can be hydrogenated in the liquid phase, at about 99% selectivity, to produce hexamethylene diamine at pressures as low as 30 atm using nickel catalysts containing iron or cobalt at about 75°C. New routes to HMD are being developed by major producers. Adiponitrile was easily hydrogenated to HMD, at pressures up to 600 atm, with a cobalt oxide catalyst containing small amoimts of silica and titania. Hydrogenation at 300-350 atm was also possible with iron catalysts. 

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