Cobalt catalysts effect

A. Sirijaruphan, A. Horvath, J. G. Goodwin, Jr and R. Oukaci, Cobalt aluminate formation in alumina-supported cobalt catalysts effects of cobalt reduction state and water vapor, Catal. Lett., 2003, 91, 89-94. 

Llorca, J. Ramirez de la Piscina, P Dalmon, J.A., Sales, J. and Homs, N, (2003) CO-free hydrogen from steamreforming of bioethanol over ZnO-supported cobalt catalyst. Effect of the metallic precursor. Appl. Catal. B, 43, 355-369. 

Lewis-acid catalysis is effective in intermolecular as well as intramolecular /zomo-Diels-Alder reactions. Thus, complex polycyclic compounds 93 have been obtained in good yield by the cycloaddition of norbornadiene-derived dienynes 92 by using cobalt catalyst, whereas no reaction occurred under thermal conditions [91] (Scheme 3.18). 

The present study revealed effects of various rutile/anatase ratios in titania on the reduction behaviors of titania-supported cobalt catalysts. It was found that the presence of rutile phase in titania could facilitate the reduction process of the orbalt catalyst. As a matter of fact, the number of reduced cobalt metal surface atoms, which is related to the overall activity during CO hydrogenation increased. 

The polymers were converted to supported catalysts corresponding to homogeneous complexes of cobalt, rhodium and titanium. The cobalt catalyst exhibited no reactivity in a Fischer-Tropsch reaction, but was effective in promoting hydroformylation, as was a rhodium analog. A polymer bound titanocene catalyst maintained as much as a 40-fold activity over homogeneous titanocene in hydrogenations. The enhanced activity indicated better site isolation even without crosslinking. 

Under relatively mild conditions the Ru/C catalyst poisoned with Sn (lines 1 and 2), the Ir/C catalyst (lines 14 and 15), and the Raney-cobalt catalyst modified with CoCl2 (line 19) seem likely systems to try when initiating a search for an effective method for selectively hydrogenating the C=0 bond in an a, 3-unsaturated aldehyde. 

Jacobs G., Das T.K., Zhang Y., Li J., Racoillet G., Davis B.H. 2002. Fischer-Tropsch synthesis Support, loading and promoter effects on the reducibility of cobalt catalysts. Appl. Catal. A Gen. 233 263-81. 

Liu Y., Zhang Y., and Tsubaki N. 2007. The effect of acetic acid pretreatment for cobalt catalysts prepared from cobalt nitrate. Catal. Commun. 8 773-76. 

Bezemer, G. L., Radstake, P. B., Falke, U., Oosterbeek, H., Kuipers, H. P. C. E., van Dillen, A., and de Jong, K. P. 2006. Investigation of promoter effects of manganese oxide on carbon nanofiber-supported cobalt catalysts for Fischer-Tropsch synthesis. Journal of Catalysis 237 152-61. 

Huang, X. W., Elbashir N. O., and Roberts, C. B. 2004. Supercritical solvent effects on hydrocarbon product distributions from Fischer-Tropsch synthesis over an alumina-supported cobalt catalyst. Industrial Engineering Chemistry Research 43 6369-81. 

Effect of a Novel Nitric Oxide Calcination on the Catalytic Behavior of Silica-Supported Cobalt Catalysts during Fischer-Tropsch Synthesis, and Impact on Performance Parameters... 

Schulz, H., Claeys, M., and Harms, S. 1997. Effect of water partial pressure on steady state Fischer-Tropsch activity and selectivity of a promoted cobalt catalyst. Stud. Surf. Sci. Catal. 107 193-200. 

Lee, D.-K., Lee, J.-H., and Ihm, S.-K. 1988. Effect of carbon deposits on carbon monoxide hydrogenation over alumina-supported cobalt catalysts. Appl. Catal. 36 199-207. 

Feller, A., Claeys, M., and van Steen, E. 1999. Cobalt cluster effects in zirconium promoted Co/Si02 Fischer-Tropsch catalysts. J. Catal. 185 120-30. 

Viswanathan, B., and Gopalkrishnan, R. 1986. Effect of support and promoter in Fischer-Tropsch cobalt catalysts. J. Catal. 99 342-48. 

Storsceter, S., Borg, 0., Blekkan, E.A., and Holmen, A. 2005. Study of the effect of water on Fischer-Tropsch synthesis over supported cobalt catalysts. J. Catal. 231 405-19. 

With cobalt catalysts, hydroformylation of ethyl cinnamate gave 91% of the hydrogenation product ethyl hydrocinnamate (15) and only 8% of the expected lactone, 16 (72). However, rhodium catalysis was effective in directing the reaction in favor of hydroformylation (70). The comparative results obtained with cobalt and rhodium are outlined in Table XXV. 

Also, nitrones can be formed by photochemical oxidation (X350 nm) of aldimines in acetonitrile, in the presence of O2 over a TiC>2 suspension (20, 21). Air oxidation of imines into oxaziridines with their subsequent transformation into nitrones, using cobalt catalysts, provides good yields. Utilization of molecular oxygen in the oxidation process seems highly promising due to its cost-effectiveness, availability, and the possibility of industrial application (22). 

Fischer-Tropsch synthesis on cobalt catalysts the effect of water... 

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