Abstract: A method for filtering a three phase reaction mixture comprising a liquid phase, an undissolved solid catalytic phase and a gas phase includes tangentially filtering through a membrane filter at least part of the three phased reaction mixture, and recycling the catalyst while recuperating at least part of the filtrate comprising the reaction products.

Abstract: The invention concerns a method for treating an aqueous solution derived from sluicing of crude mononitrated or dinitrated aromatic compounds obtained by nitration of the corresponding aromatic compounds, consisting in: (a) contacting said aqueous solution with said aromatic compound thereby obtaining an aqueous phase and an organic phase; (b) recycling said organic phase in the nitration process; (c) distilling said aqueous phase; (d) recycling the resulting concentrated acid solution in the nitration process; (e) recycling or eliminating the recuperated water after distillation.

Abstract: A method for purifying lactams by liquid-liquid extraction and/or processing with an ion exchange resin is disclosed. The method is useful for purifying lactams produced by the cyclising vapour-phase hydrolysis of an aliphatic aminonitrile, and comprises removing the major part of the ammonia before subjecting the lactam to liquid-liquid extraction by means of a solvent including an acidic solvent and/or contacting said lactam with a cation exchange resin. In most applications of the lactam, it is preferable to carry out a hydrogenation step on the compounds of the lactam solution comprising unsaturations, prior to or in addition to the liquid-liquid extraction step and/or the acidic resin contact step. The purification method may also include an oxidation step in addition to or instead of the hydrogenation step. Said method is preferably combined with a distillation step in the presence of a base.

Abstract: Preparation of carboxylic acids or corresponding esters by reacting an alcohol with carbon monoxide in the presence of an iridium catalyst and a halogen promoter. The reaction involves a reaction mixture composed of more than 0% to 10% water, more than 0% to 10% halogen promoter, 2% to 40% of an ester corresponding to the reaction of alcohol with the acid, soluble iodides in an amount such that the atomic ratio of iodides to iridium varies between more than 0 and 10, the carboxylic acid being used as the reaction solvent.