Hoechst Celanese Corporation

Other

Gary L Moss

Edward G Zey

Kenneth G Davenport

Siegbert Rittner

Brad L Smith

Graham N Mott

Varadaraj Elango

Mark A Murphy

Debra A Ryan

Thomas H Shockley

Adolf Schmidt

Larry O Wheeler

2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.

Process for purifying 2-(4-isobutylphenyl)-propionic acid by vacuum

This invention pertains to a method of purifying ibuprofen-comprising reaction product mixtures. The method of purification is based on crystallization of ibuprofen from a hydrocarbon solvent and the discovery that there are impurity complexes in the ibuprofen-comprising reaction product mixtures which cannot be removed by crystallization from a hydrocarbon solvent. The method of the invention includes at least one step in which the impurity complex in a first ibuprofen-comprising mixture is destabilized or broken up, followed by crystallization of the ibuprofen from a second solution or mixture comprising the first ibuprofen-comprising mixture, whereby the impurities which were previously complexed can then be removed from the ibuprofen by the crystallization of ibuprofen from a solvent.

Method for purification of ibuprofen comprising mixtures

A method is provided for the preparation of ibuprofen by carbonylating 1-(4'-isobutylphenyl)ethanol (IBPE) with carbon monoxide in an acidic aqueous medium, e.g. containing at least 10% of water based on the weight of IBPE initially added, at a temperature of at least about 10.degree. C. and a carbon monoxide pressure of at least about 500 psig, and in the presence of (1) a catalyst complex consisting essentially of a palladium compound in which the palladium has a valence of zero to 2 and is complexed with at least one monodentate phosphine ligand miscible with the organic phase of the reaction medium, the phosphorus/palladium mole ratio in said palladium compound and ligand being at least about 2:1 when the palladium/IBPE mole ratio is such that palladium=1 and IBPE=10,000 or more; (2) dissociated hydrogen ions from an acid which is substantially completely ionizable in dilute aqueous solution such that the mole ratio of hydrogen ions to IBPE added to the reaction zone is at least about 0.15; and, (3) dissociated halide ions such that the mole ratio of halide ions to IBPE added to the reaction zone is at least about 0.15. Advantageously, a hydrogen halide is the source of hydrogen ions and halide ions. The carbonylation is preferably integrated with a method of producing IBPE from isobutylbenzene wherein the latter compound is subjected to Friedel-Crafts reaction with an acetylating agent to produce 4-isobutylacetophenone, which is then reduced with hydrogen in the presence of a hydrogenation catalyst, or with a reducing agent containing available hydrogen, to obtain IBPE. The palladium catalyst complex can be precipitated from an organic phase of the carbonylation reaction which typically includes the ibuprofen product. The precipitated catalyst complex can be recycled without further treatment.

Method for producing ibuprofen

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Corpus Christi, TX, United States of America

Gary L Moss