CHARACTERIZATION OF SOME IRON CATALYSTS FOR THE REDUCTION OF CARBON MONOXIDE AND THE EFFECT OF RESIDENCE TIME AND TEMPERATURE ON THE NATURE OF CARBON MONOXIDE REDUCTION PRODUCTS (FISCHER-TROPSCH, HYDROGENATION, METHANATION)

Methanation studies have been carried out at 290(DEGREES)C in a microreactor with a H(,2)/CO ratio of 9/1. The catalysts studied were iron(III) oxide, iron(II) diiron(III) tetroxide, and metallic iron. These were all prepared reproducibly from iron(III) nitrate. The catalysts were characterized by x-ray diffraction and magnetic analysis both at maximum activity and after deactivation. All catalysts at maximum activity contained (chi)-Fe(,2)C(,2). Deactivation of the catalysts was found to be due to excess graphitic carbon. Sustained catalytic activity was found to require the presence of iron(II) diiron(III) tetroxide, probably to serve as a source for continual renewal of the active catalyst surface.; The reduction of carbon monoxide by hydrogen was carried out at ambient pressure in a microreactor with a H(,2)/CO ratio of 9/1 using bulk iron(III) oxide as the catalyst. A technique was developed to study the effects of residence time and temperature on the carbon monoxide reduction products without changing the composition of the catalyst. The extent of hydrogenation of primary olefin products was found to decrease with increasing space velocity of the synthesis gas. Greater chain growth of hydrocarbon products was observed at lower temperature.