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A Method To Produce A Mixture Of Acetic Acid, Acetaldehyde, Ethanol And C2-C4 Olefins

Abstract

This invention relates to the production from synthesis gas of oxygenated C₂-hydrocarbons and lower olefins, in particular, a mixture of acetic acid, acetaldehyde, ethanol, ethylene and propylene. Molar ratio of oxygenated hydrocarbons to lower olefins ranges within (1-2.5):1. The process is carried out in the gas phase at 150-350°C and 1-300 atmospheres in the presence of rhodium catalyst. To increase the olefins yield, the catalyst is applied containing 0.1-15 wt.% Rh and 0.1-5.0 wt.% of an alkali metal compound selected from a group of sodium acetate, lithium acetate, potassium acetate, sodium chloride, cesium chloride, sodium nitrite, rubidium nitrite, supported on silicic acid. The presence of small amounts of alkali metal ions in the catalyst facilitates the olefin formation, diminishes the conversion of synthesis gas to methane and considerably increases the catalyst activity.

Process for the manufacture of mixtures of acetic acid, acetaldehyde, ethanol and olefins having two to four carbon atoms in a 1:1-2.5:1 molar ratio of the said oxygen-containing compounds to the olefins, by reacting carbon monoxide and hydrogen in the presence of catalysts containing rhodium and, if appropriate, promoters, in the gas phase at temperatures between 150 and 350^oC and under pressures between 1 and 300 bars, characterized in that the catalysts contain 0.1 to 5.0 % by weight of sodium or potassium which are applied by impregnation with corresponding oxides, hydroxides, salts or complex compounds with the exception of double salts or rhodium or magnesium with sodium or potassium halides and of potassium rhodium cluster complexes.