according to the invention may very suitably be obtained from a heavy carbonaceous material such as coal by gasification or from light hydrocarbons such as natural gas by steam reforming or partial oxidation suitable h 2 and co containing feeds may also be obtained by separating a fraction containing unconverted hydrogen and carbon monoxide and other components if desired from the reaction product obtained by contacting a h 2 co mixture with a catalyst containing one or more metal components having catalytic activity for the conversion of a h 2 co mixture into hydrocarbons and or oxygen containing organic compounds in this partial conversion of the h 2 co mixture depending on the catalyst chosen therefor there will be produced either mainly aromatic hydrocarbons or mainly paraffinic hydrocarbons or mainly oxygen containing organic compounds if in the partial conversion it is the object to produce mainly aromatic hydrocarbons use can very suitably be made of a catalyst mixture containing either a methanol or dimethyl ether synthesis catalyst or a fe mg al 2 o 3 or fe cr sio 2 catalyst prepared by impregnation together with a crystalline metal silicate which is characterized in that after one hour 39 s calcination in air at 500 u00b0 c it has the following properties a an x.