Abstract: Catalyst particles are contacted with a liquid and a gas in a vertically extending cylindrical vessel. The particles and liquid are placed in the vessel into which the gas and liquid are continuously fed from the bottom thereof so that an upwardly flowing mixture comprising the particles, liquid and gas is formed. The mixture is introduced into a gas separating zone disposed adjacent to an upper portion of the vessel to separate the mixture by gravity into a gas phase, a supernatant liquid phase and a phase rich in the catalyst particles. The gas and supernatant phases are continuously withdrawn from the separating zone while the catalyst particles-rich phase is continuously recycled to the bottom of the vessel by gravity.

Abstract: Catalyst particles are contacted with a liquid and a gas in a vertically extending cylindrical vessel. The particles and liquid are placed in the vessel into which the gas and liquid are continuously fed from the bottom thereof so that an upwardly flowing mixture comprising the particles, liquid and gas is formed. The mixture is introduced into a gas separating zone disposed adjacent to an upper portion of the vessel to separate the mixture by gravity into a gas phase, a supernatant liquid phase and a phase rich in the catalyst particles. The gas and supernatant phases are continuously withdrawn from the separating zone while the catalyst particles-rich phase is continuously recycled to the bottom of the vessel by gravity.

Abstract: In the production step, alcohol is reacted with carbon monoxide in a reaction solvent in the presence of a rhodium-containing solid catalyst obtained by immobilizing rhodium in an insoluble carrier (I) containing a pyridine ring in its resin structure and an alkyl iodide containing an alkyl group of 1 to 5 carbon atoms, to produce a reaction product having a water content of 0.5 to 10% by weight; and in the subsequent removing step, an organic carboxylic acid is separated and recovered from the reaction product, and the recovered organic carboxylic acid is contacted with an insoluble carrier (II) containing a pyridine ring in its resin structure, to remove an iodide contained in the organic carboxylic acid.

Abstract: A methanol carbonylation catalyst includes a rhodium complex supported on a porous, cross-linked vinylpyridine resin, wherein the vinylpyridine resin has a cross-linking degree of 30-60%, a pore volume of 0.1-0.4 ml/g and an average pore diameter of 20-100 nm. The catalyst may be prepared by contacting the pyridine ring-containing resin with an aqueous solution containing rhodium ion and then contacting the resulting rhodium ion-carrying resin with carbon monoxide and an alkyl iodide in an organic solvent to convert the rhodium ion to a rhodium complex bound to the resin. Acetic acid is produced by reacting carbon monoxide with methanol at a temperature of 140.degree.-250.degree. C. and a partial pressure of carbon monoxide of 7-30 kg/cm.sup.2 in the presence of an alkyl iodide and the above catalyst.

Abstract: A liquid feed containing methanol, carbon monoxide, an alkyl iodide and a solvent is contacted with a supported rhodium catalyst to produce acetic acid at a temperature of 140.degree.-250.degree. C. and a pressure of 15-60 kg/cm.sup.2 G with a partial pressure of carbon monoxide of 7-30 kg/cm.sup.2 while maintaining (a) the water concentration of the product solution in the range of 0.5-10% by weight and (b) the carbonylation degree C.sub.r, defined in the specification, of the solution within the reactor at 0.15 or more. The solvent may be a carboxylic acid or a carboxylic acid ester.