CO hydrogenation over

This review covers the personal view of the authors deduced from the literature starting in the middle of the Nineties with special emphasis on the very last years former examples of structure-sensitive reactions up to this date comprise, for example, the Pd-catalyzed hydrogenation of butyne, butadiene, isoprene [11], aromatic nitro compounds [12], and of acetylene to ethylene [13], In contrast, benzene hydrogenation over Pt catalysts is considered to be structure insensitive [14] the same holds true for acetonitrile hydrogenation over Fe/MgO [15], CO hydrogenation over Pd [16], and benzene hydrogenation over Ni [17]. For earlier reviews on this field we refer to Coq [18], Che and Bennett [9], Bond [7], as well as Ponec and Bond [20]. 

Guczi, L., Stefler, G., Geszti, O., Koppany, Zs., Molnar, E., Urban, M., and Kiricsi, I. 2006. CO hydrogenation over cobalt and iron catalysts supported over multiwall carbon nanotubes Effect of preparation. Journal of Catalysis 244 24—32. 

Mirodatos, C., Brum Pereira, E., Gomez Cobo, A., Dalmon, J. A., and Martin, G. A. 1995. CO hydrogenation over Ni- and Co-based catalysts Influence of alkali addition on morphological and catalytic properties. Top. Catal. 2 183-92. 

The influence of water on the rate of CO hydrogenation over y-Al203-supported cobalt catalysts has been the subject of several studies. Table 2 gives an overview of the reported effects. As can be seen the observed effects range from negative to positive, for a range of catalyst compositions and supports used. There are also examples of this effect in the patent literature, e.g. Eri et al,44 who addressed the effect of water on an a-Al203 supported cobalt catalysts. When the inlet water partial pressure was 4.6 bar, the CO conversion increased from 24 to 30%. Thus, a positive impact of water was recorded. 

Table 2 Experimental results on the influence of added water on the rate of CO hydrogenation over alumina-supported cobalt-catalysts. Reaction conditions 483 K, ratio H2 CO = 2.0-2.1 1, P — 20 bar (unless otherwise indicated)... 

Tlte first reports on heterogeneous CO hydrogenation over nickel catalysis to give methane were made in 1902 by Sabatier and Senderens. The reaction was carried out at normal pressure at 200-300 C [16]. 

The classical experiments of F. Fischer and H. Trupsch date back to 1922, when the CO hydrogenation over alkalized iron catalysis at high pressures (150 bar) and temperatures (400-4S0 C) was found to yield oxygen-containing products ( Synihol ) I8]. 

Feeds wttn >5% (Carbon Atom) CO Feed Show No Label In Product CO) Hydrogenation Over Iron Carbon Catalysts Provids an Efflcisnt... 

Carbon Deposition Effects on CO Hydrogenation over Alumina-and Y Zeolite-supported Cobalt Catalysts S.-K. IhJn, D.-K. Lee... 

CARBON DEPOSITION EFFECTS IN CO HYDROGENATION OVER ALUMINA- AND Y ZEOLITE-SUPPORTED COBALT CATALYSTS... 

Table III. Kinetic Results of CO Hydrogenation over Nickel Catalysts...

King (52) performed in situ IR spectroscopy of CO hydrogenation over SiO2- and AI2O, -supported ruthenium and over SiO2-supported iron. Compared to the two previous studies (57, 57) this author applied considerably higher pressures up to 3 bars. With all the catalysts a substantial amount of C-H derived bands in the 3000 cm region developed. No evidence such as deuterium substitution has been presented to prove or disprove that these species are reactive intermediates. 

TABLE 1 Activity and Product Distribution of CO Hydrogenation over Molybdenum Zeolite Catalysts... 

Vannice, M.A. Lam, Y.L. and Garten, R.L. "CO hydrogenation over well-characterized Ru-Fe alloys." Preprints, American Chemical Society Division of Petroleum Chemistry. 23 495-501 1978. 

The synthesis of hydrocarbons from CO hydrogenation over transition metals is a major source of organic synthetic chemicals and fuels. The Fischer-Ttopsch (FT) reaction, which is directed to the production of hydrocarbons from syngas, implies the polymerisation of-CHx entities and carbon-carbon bond formation is required. The historical achievements have been revised on several occasions see for instance, the reviews by Vannice,2 Schulz3 and the special issue of Catalysis TodayA devoted to FT. Also, a synopsis of the main recent industrial developments has been presented by Adesina.5 Furthermore, the recent edition of Topics in Catalysis6 should be mentioned, where different aspects of the reaction mechanism, surface reconstruction of active surfaces, improved reactors and optimisation of catalyst preparations have been treated by various specialists, scientists and engineers. 

Methanol and dimethyl ether have been coproduced by CO hydrogenation over Pd/NaY catalysts prepared by ion exchange. By controlling the calcination program, Pd/NaY catalysts can be tuned to selectively produce either branched... 

Fig. 10. A comparison of the product distributions (weight percent) over a Ni(IOO) catalyst observed during CO hydrogenation over clean (solid bars) and K-doped (cross-hatched bars) catalysts at T = 500 K, H2 CO = 4 1, and a total pressure of 120 torr. Potassium coverage = 0.10 monolayers (ML). From Ref. 127.

Fig. 18. Turnover frequencies for CO hydrogenation over a series of Rh/Ti02 catalysts as a function of the pH of the solution used in the impregnation step in the preparation following reduction at 473 K (solid points) following reduction at 773 K (open points). (Data taken from Ref. 46.)...

Figure 7.32. Effect of support on CO hydrogenation over Ni catalysts [193].

All of the species are reacting in their adsorbed states. If enol species form as reaction intermediates as suggested for CO hydrogenation over molybdenum, the elementary surface reaction sequence may be expressed as follows ... 

D.J. Dwyer and G.A. Somoijai. The Role of Readsorption in Determining the Product Distribution During CO Hydrogenation over Fe Single Crystals. J. Catal. 56 249 (1979). 

Table 1. Effect of content of second metal on yield of ceresins in CO hydrogenation over Co-M/AljOjcatalyst (H2/CO=2.2 P=0.95 MPa, T=177°C, S.V.= 100 hr )...

Two sets of gas phase on-line data for the catalytic reaction of CO hydrogenation over ZnO and Au supported on ZnO is shown in Figure 4(a) and (b) respectively. An average conversion of ca. 20% was achieved with only ZnO powder as the catalyst in Figure 4(a), which is much higher than the ca. 6% conversion observed with 5%Au/ZnO as the catalyst. Meanwhile, the percentage of hydrocarbons decreased from ca. 0.36% to ca. 0.26% for methane and from a maximum of ca. 0.17% to a maximum of ca. 0.07% for other hydrocarbons. The decreased conversion could be partially attributed to the decreased production of hydrocarbons. 

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