ISSN:
0930-7516
Schlagwort(e):
Chemistry
;
Industrial Chemistry and Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
Notizen:
The hydrogenation of CO over supported cobalt catalysts has been studied using in situ FTIR spectroscopy and gravimetry at P = 6 bar, T = 473-723 K and H2/CO = 2-3. On both silica- and alumina-supported catalysts IR absorption bands corresponding to linearly adsorbed CO on metallic cobalt were observed. On alumina an additional pair of bands at lower frequencies was attributed to bridge-bonded CO. Absorption bands corresponding to adsorbed hydrocarbons (3050-2700 cm-1) and to oxygen containing species (1800-1200 cm-1) were found to correspond to adsorbed products or unreactive species. The gravimetric studies showed a significant difference between the supports. On the silica-supported catalyst the weight uptake decreased with increasing temperature (473-573 K). The weight increase during reaction was attributed to adsorbed hydrocarbon reaction products. On the alumina-supported catalyst the weight uptake increased with increasing temperature, and there was also a significant weight increase with the support alone. Most of the weight uptake can be attributed to the formation of stable formate and carbonate species on the alumina support. At 723 K the deposits formed were stable in H2, and the shape of the curves indicated different mechanisms for deposition of material. In particular the Co/Al2O3 sample showed a very high and linear rate of weight gain, which was an order of magnitude higher than for the other samples.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/ceat.270180207
