Carbon platinum catalysts

The temperature dependence of the selectivity for isomerization versus hydrogenolysis depends on the type of catalyst. Thus, over thick platinum film catalysts this selectivity was temperature independent for the reaction of the butanes and neopentane (24). However, in Boudart and Ptak s (122) reaction of neopentane over platinum/carbon the selectivity to isomerization decreased slightly with increasing temperature while Kikuchi et al. (128) found an increased trend for isomerization in the reaction of n-pentane over platinum/silica and platinum/carbon catalysts. 

The activity of the platinum-carbon catalyst is of prime concern in obtaining maximum yields of product in a minimum of time. It was found by Mehltretter and his associates14 that a modification of Trenner s procedure02 consistently produced an effective catalyst. In the modified method, platinum from an aqueous solution of chloroplatinic acid was deposited on acid-washed Darco G-60 brand of activated carbon by means of formaldehyde and sodium carbonate. To maintain high activ-... 

The effect of hydrogen on naphthenic hydrocarbons is mainly that of ring scission followed by immediate saturation of each end of the fragment produced. The ring is preferentially broken at favored positions, although generally all the carbon-carbon bond positions are attacked to some extent. For example, methyl-cyclopentane is converted (over a platinum-carbon catalyst) to 2-methylpentane, 3-methylpentane, and n-hexane. 

Asymmetric hydrogenations have been reported with palladium on silk 123>, palladium on modified cellulose 124> and on modified ion exchange resins 125 >. Also with Raney Nickel modified with amino adds 126> and peptides, 27>. Platinum-carbon catalysts exhibiting shape selectivity have been made by coating them with a thermosetting resin, which is carbonized. In such a way an organic molecular sieve skin is formed over the original catalyst 128>. 

Cooper, B. J. Platinum-Carbon Catalysts with Molecular Sieve Properties. Shape Selectivity in Hydrogenation Catalysis. Platinum Metals Rev, 14, 133 (1970). 

Catalytic hydrogenation has been applied to materials of widely varying molecular weights and structures. Thus, materials such as wood, rubber, vitamins, proteins, steroids, elastomers, cotton linters, and nylon are typical of the variety of compounds subjected to the reaction. Further, nitric oxide on hydrogenation over a platinum-carbon catalyst yields hydrox-ylamine—such a process has commercial possibilities. 

Orito, Y., Imai, S., Niwa, S., Nguyen, G.H. (1979) Asymmetric hydrogenation of methyl benzoylformate using platinum-carbon catalysts modified with cinchonidine, J. Synth. Org. Chem. Jpn. Yuki Gosei Kagaku Kiokaishi) 31, 173-174. 

Niwa, S., Imai, S., Orito, Y. (1982) Asymmetric hydrogenation of ethyl benzoylformate using the platinum-carbon catalyst modified with cin-chonidine-influence of preparation of the catalyst on the asymmetric selectivity, J. Chem. Soc. Jpn. Nippon Kagaku Kaishi) Nl, 137-138. 

Reiner A, Hajbolouri F, Dbbeli M, Wokaun A and Scherer G G (2005) Co-Sputtering A Novel Platinum-Carbon Catalyst Preparation Method, 3rd European PEFC Forum, Lucerne, Poster 109. 

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