Method for the preparation of ibuprofen

The present invention relates to a method for preparing ibuprofen, characterized in that comprises carbonylating 1- (4'-isobutylphenyl) ethanol (IBPE) with carbon monoxide in an acidic aqueous medium at a temperature of at least 10C and a pressure of carbon monoxide of at least 35 kg / cm to gauge square, and in the presence of (1) a catalyst consisting essentially of a palladium compound in which the palladium has a valence of 0 to 2 and forms a complex when least one ligand or coordinator molecule monodentate phosphine stable Miscible acid with the organic phase of the reaction medium, the molar ratio fosfaro / palladium in said compueto palladium and the coordinator molecule is at least about 2: 1 when the molar ratio of palladium to IBPE is such that the palladium 1 and IBPE 10,000 or greater; (2) hydrogen ions dissociated from an acid which is ionizable in a substantially completely in a dilute aqueous solution such that the molar relaion of hydrogen ions to IBPE added to the reaction zone is cuandomenos 0.15; and (3) dissociated halide ions, such that the molar ratio of halide ions to IBPE of added to the reaction zone is at least about 0.15.