Hoechst Celanese Corporation

Joel D Hendricks

G Paull Torrence

Graham N Mott

Adolfo Aguilo

Dennis D Dickinson

A method is provided for the preparation of ibuprofen by carbonylating 1-(4'-isobutylphenyl)ethanol (IBPE) with carbon monoxide comprising initially a reaction mixture comprising IBPE, ibuprofen and a catalyst for the carbonylation with carbon monoxide under conditions to initiate the reaction, and continuing to feed carbon monoxide to the composition to produce the desired yield of ibuprofen. Preferably the catalyst comprises palladium and a monodentate phosphine ligand. The presence of ibuprofen in the feed composition when the reaction is initiated with CO makes it possible to obtain high selectivities to ibuprofen with substantially complete conversion of IBPE at much shorter reaction times than if no ibuprofen is present initially.

Method for producing ibuprofen

The carbonylation of an alcohol to produce a carboxylic acid, especially methanol to produce acetic acid, in a low water reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions is improved by the addition of hydrogen in the feed gas to the low water reaction medium to obtain a reactor hydrogen partial pressure of at least about 4 psi. The presence of hydrogen in the reaction medium increases significantly the carbonylation reaction rate and reduces formation of byproduct carbon dioxide. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e., it is resistant to catalyst precipitation out of the reaction medium.

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Pineville, NC, United States of America

Joel D Hendricks