Hydrocarbon synthesis from co and h.sub.2 using ni supported on a

Abstract

Nickel supported on TiO.sub.2, other titanium-containing oxides or mixtures of various titanium oxides results in a catalyst system which exhibits superior hydrocarbon synthesis characteristics. Such supported nickel catalysts exhibit selectivity to paraffinic hydrocarbon products of from C.sub.2 to C.sub.7 which are free of olefins and oxygenated products. They generate CO conversions of up to 60% at pressures of 3090 kPa without significant change in product distribution. A large fraction of the product obtained contains 2 or more carbon atoms in the chain up to conversions of 60%. The supported nickel catalysts exhibit enhanced activity, improved selectivity to higher molecular weight normal paraffins, improved longevity and tolerance to sulfur and resistance to nickel carbonyl formation as compared to nickel catalysts on other supports such as Al.sub.2 O.sub.3, silica or carbon. A new method for the selective synthesis of higher molecular weight normal paraffins from CO and H.sub.2 over a wide range of CO conversions at pressures of from 103 to 3090 kPa (1 atm=103 kPa) which method comprises the steps of passing a synthesis gas stream of CO and H.sub.2 at a ratio of from 2 moles CO per .2 to 20 moles H.sub.2 at a space velocity of from 100 hr..sup.-.sup.1 to 30,000 hr..sup.-.sup.1 over a catalyst comprising from 0.01 to 75 wt. % nickel on TiO.sub.2, other titanium-containing oxides or mixtures of said titanium-containing oxides for a time sufficient to effect the generation of desired paraffinic products, at a temperature of from 100 to 500.degree. C. and a pressure of from 103 to 1.03 .times. 10.sup.5 kPa. The supported nickel catalyst has a BET surface area of from 10 to 60 m.sup.2 g.sup..sup.-1 of total catalyst with a nickel crystallite size of < 10 nm (100 A).