Patent GB-777825-A (GB)
Title: Process for the hydrogenation of carbon monoxide
IPC: B01J23/78
Filed: 1953-11-03
Abstract: Oxygen-containing organic compounds, predominantly esters and alcohols, and hydrocarbons are produced by passing a mixture of carbon monoxide and hydrogen in the ratio of from 1 : 0.5 to 1 : 10 at 150-300 DEG  C. and at a pressure of not less than 10 atmospheres, preferably 30-50 atmospheres, over a reduced catalyst containing iron, copper and barium co-precipitated from a common solution of salts, and an alkali metal compound, the barium oxide content being from 10-50 parts, the copper content being more than 25 parts and the alkali metal content (calculated as K2O) being more than 2 parts, per 100 parts of iron, and more than 50 per cent of the iron being in the metallic state. The CO : H2 ratio in the synthesis gas is preferably from 1 : 1 to 1 : 2 and the preferred temperature is 180-250 DEG  C. The use of a CO : H2 ratio within the range 1 : 0.5 to 1 : 1 gives an increased yield of high molecular weight oxygen-containing compounds, predominantly esters, whilst an increase in the hydrogen content to a CO : H2 ratio less than 1 : 2 gives an increased yield of alcohols. Aldehydes, ketones, acids and olefines are also produced.  The use of gas recycling with a ratio of recycled gas: fresh gas of 1 : 1 to 3 : 1 is preferred, but the synthesis may be operated with once-through operation.  The synthesis may be operated with single, two, or multi-stage operation with CO2 scrubbing units between stages.  A space velocity of 200-500 volumes of gas per volume of catalyst per hour is preferable, to give an increased yield of alcohols boiling between 200-300 DEG  C. as compared with a gas load of 100 v./v./hr. The catalyst preferably contains 10-30 parts of barium oxide, 50-200 parts of copper, and more than 5 parts of alkali (calculated as K2O) per 100 parts by weight of iron, more than 75 per cent of the iron being in the metallic state.  (For preparation see Group III.)  The catalyst preferably contains no supporting material or not more than 10 per cent of supporting material based on the total weight of iron. An inner surface area of catalyst of 10-110 square metres per gram of iron is advantageous, the optimum being 30-80 square metres. Examples using water gas at 30 atmospheres as the synthesis gas in double-tube reactors show the effect of variation in temperature from 195-260 DEG  C., space velocity from 100-500 v./v./hr. and catalyst composition.ALSO:An iron catalyst containing copper, barium and an alkali-metal compound with no support or with a support material which constitutes not more than 10 per cent by weight of the iron, the barium oxide content of the catalyst being from 10-50 parts, preferably 10-30 parts, the copper content being more than 25 parts, preferably 50-200 parts, and the alkali-metal content (calculated as K2O) being more than 2 parts, preferably more than 5 parts, per 100 parts by weight of the total iron in the catalyst.  More than 50 per cent, preferably more than 75 per cent, of the iron in the catalyst is advantageously in the metallic state.  The catalyst may be produced by precipitating the iron, copper and barium from an aqueous solution of their salts with alkali at the boil, the pH of the suspension after precipitation being above 7 and preferably above 8.2 but less than 10.  The catalyst mass is then filtered hot and washed to obtain the desired alkali metal content.  Alternatively a total wash may be effected, the desired alkali metal being subsequently incorporated by impregnation.  Suitable alkali-metal compounds are the hydroxides, carbonates, bicarbonates, formates, oxalates, phosphates, silicates or borates.  The catalyst is then moulded, for example in an extrusion press, if necessary after reducing the water content to 50-70 per cent, and finally dried at 100 DEG C., crushed and sieved.  The catalyst may also be brushed on to metal plates, dried at 100 DEG C. and then crushed and sieved. Particle size from 0.5 mm. to between 1.5-3 mm. are suitable. The catalyst may be reduced at normal, subatmospheric or superatmospheric pressure.  At normal pressure a gas flow velocity of 50-200 cm./second is suitable, while at superatmospheric pressure a gas flow velocity of 5-30 cm./sec. is preferred.  The reduction may be effected with gases containing hydrogen and/or carbon monoxide at 150-300 DEG C. preferably 250-300 DEG C.  The reducing gases should preferably have a water content below 1 gram per cubic metre, more preferably below 0.1 gram per cubic metre.  In an example, a catalyst is precipitated from a boiling solution of iron, copper and barium in the form of nitrates by adding the solution to a boiling solution of sodium carbonate.  The precipitate is washed, impregnated with potassium carbonate, brushed on to metal plates, dried and crushed to a size of 2-4 mm. Other catalysts containing calcium and strontium instead of barium are prepared for comparison.  The catalysts are reduced with a hydrogen-nitrogen mixture at 320 DEG C. and normal pressure. The catalysts are used for the hydrogenation of carbon monoxide (see Group IV(b)).