GB454948A - Method of increasing yield in the catalytic synthesis of aliphatic hydrocarbons - Google Patents

Abstract

Aliphatic hydrocarbons containing more than one carbon atom, particularly liquid hydrocarbons, are produced by reacting mixtures of carbon monoxide with at least an equal volume of hydrogen in the presence of catalysts, at ordinary or slightly increased or reduced pressure, and at temperatures of 180--200 DEG C., the reaction being effected in at least two stages with intermediate removal of all or part of the condensible reaction products, and in the early stages conditions being so chosen that the gases are only partly converted, for example by operating at low temperatures within the range, or by using a deficiency of hydrogen or high velocities. The gas mixture may traverse a cycle with one or more contact stages and then, after removal of reaction products, be completely converted in a further stage. In examples: (1) a mixture of 2 parts H2 and 1 part CO is passed over three layers of cobalt in succession, the reaction products, oil, benzine, and water, being removed after passing each layer. The temperature is selected so that no more than one third of the CO is converted in each stage, for example, 182 DEG C. in the first stage, 187 DEG C. in the second, and 193 DEG C. in the third. Alternatively, two layers may be disposed in parallel and, after removal of reaction products, the gases passed over a third layer. Temperatures may be 184 DEG C. in the first stage and 195 DEG C. in the second; (2) two stages at 180 and 200 DEG C. are employed, light benzine and lower boiling hydrocarbons being removed intermediately as by washing with cold oil or the use of active carbon; (3) as in (2) all the reaction products being removed, the oil by washing with an oil at above 100 DEG C., the water with water, unsaturated gaseous hydrocarbons with H2SO4, and saturated gaseous hydrocarbons with active carbon; (4) insufficient hydrogen is used in the first stage and after each stage only so much hydrogen is added as will limit the conversion.