PURPOSE: A carbon monoxide and hydrogen mixed gas is subjected to catalytic reaction on a catalyst of Pt and Ru supported on a carrier such as zeolite to produce gasoline-fraction-rich and high octane value hydrocarbons, because of its high isoparaffin content.
CONSTITUTION: The catalytic reaction of a synthesis gas is carried out on the catalyst of Pt and Ru supported on a carrier to give the titled hydrocarbons. As the carrier, is preferably used an HY-type zeolite of 10-13 Angstrom pore diameter and preferably an aqueous solution of Pt(NH3)4Cl2 and Ru(NH3)6Cl3 is added thereto to effect ion exchange between Na or H ions and Pt or Ru ions, thus producing a catalyst in which the catalyst metals are homogeneously dispersed on the carrier. The amount of Pt and Ru is, preferably 0.5-5 wt% and the ratio of Ru/Pt is 0.5-2.
EFFECT: The reactions proceed smoothly and the carbon formation and change of the catalyst with time are also improved.