Method for preparing alpha-(-4-isobutylphenyl) propionic acid or its precursor.

摘要

A method for preparing alpha -(4-isobutylphenyl)propionic acid or its precursor is here disclosed which comprises the following steps (I), (II) and (III): step (I): subjecting isobutylbenzene and a polyalkylbenzene to disproportionation reaction in order to form p-isobutylethylbenzene step (II): dehydrogenating p-isobutylethylbenzene obtained in the step (I) to form p-isobutylstyrene, and step (III): the following step (IIIa) or (IIIb): step (IIIa): reacting p-isobutylstyrene obtained in the step (II) with carbon monoxide and hydrogen to prepare alpha -(4-isobutylphenyl)propionaldehyde, or step (IIIb): reacting p-isobutylstyrene obtained in the preceding step (II) with carbon monoxide and water or a lower alcohol to prepare alpha -(4-isobutylphenyl)propionic acid or its alkyl ester.