β Scribed by Ahmed M. Gadalla; Ting Chan; Rayford G. Anthony
No coin nor oath required. For personal study only.
Six catalysts consisting of mixtures of catalysts for methanol synthesis and its conversion to hydrocarbons were prepared by mechanical mixing, impregnation, and coprecipitation, followed by extrusion. Phase changes occurring during various stages of preparation and after use were followed by x-ray diffraction. The catalysts were found to be nontrivial bifunctional catalysts which selectively convert synthesis gas directly to low molecular weight hydrocarbons in the range of C1 to Cq. Methanol and dimethylether were detected as intermediates. Olefins were formed, and their further hydrogenation yielded products with high paraffinic content. Carbon dioxide retards the conversion of synthesis gas to hydrocarbons, whereas steam retards the hydrogenation of olefins. On heating the commercial zinc chromite catalyst, dehydration, reduction, and solid-state reactions occur with the formation of ZnO-ZnCrzO4 solid solution. Exchanging cations within the zeolite component did not affect the space lattice, but these ions tend to occupy special sites, and during service more order was detected. Copper ions tend to diffuse in ZnO, forming a solid solution, and during service metallic copper was produced.
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