Both iron oxide (Fe2O3) and iron carbide catalysts are active for the dehydration of tertiary alcohols; the oxide catalyst is not reduced nor is the bulk carbide oxidized by the steam generated during the dehydration reaction. Secondary alcohols are selectively converted to ketones plus hydrogen by both the iron oxide and carbide catalyst. Fe2O3 is reduced to Fe3O4 during the conversion of secondary alcohols. Both iron carbide and oxide catalysts dehydrogenate a primary alcohol (C-n) to an aldehyde which undergoes a secondary ketonization reaction to;produce a symmetrical ketone with 2n-1 carbons. These results plus those of our earlier C-14-tracer studies suggest that dehydration of alcohols to produce olefins makes a minor, if any, contribution during Fischer-Tropsch synthesis with an iron catalyst at low and intermediate pressure conditions.