Olefins � together with paraffins - are the major product compounds of Fischer-Tropsch synthesis with cobalt- and iron catalysts as well. In technical FT-operation olefins for use as chemicals may be the desired products, obtained at high selectivity with alkalized iron catalysts at high temperature. At lower temperature and less alkalization iron catalysts may behave rather similar to cobalt catalysts, producing mixtures of paraffins and olefins of various composition, mainly for use as high quality clean fuels.Understanding of the interrelated paraffin- and olefin selectivity is difficult, due to mechanistic complexity, involving also olefin secondary reactions on distinct catalytic sites and lacking of experimental methods. Principle problems being addressed are the differences of iron and cobalt as catalytic materials, both only attaining a steady state of composition and structure after some time of reaction and changes of rate and product composition.A comprehensive view of the principles ruling FT-olefin selectivity is being developed. As a main conclusion it is proposed, that secondary olefin isomerization and hydrogenation proceed on sites of metallic character, whereas pure primary olefin selectivity concerns (reversible) formation of a-olefins, as obtained on carbidic alkalized iron catalysts.Excessive methane selectivity is linked to metallic properties of FT-catalysts

Principles of olefin selectivity in Fischer-Tropsch synthesis on iron- and cobalt catalysts

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.