METHOD FOR PRODUCING ALPHA-(P-ISOBUTYL PHENYL) PROPIONIC ACID OR ITS ALKYL ESTERS

摘要

A method for producing alpha -(p-isobutylphenyl)propionic acid or its alkyl esters which is characterized in that starting materials are inexpensive, processes are easy to be done and products are highly pure. The method comprises the steps of (I): catalytically cracking 1,1-bis(p-isobutylphenyl)ethane at temperatures in the range of 200 DEG to 650 DEG C. in the presence of a protonic acid catalyst and/or a solid acid catalyst to produce isobutylbenzene and p-isobutylstyrene; and (II): reacting said p-isobutylstyrene with carbon monoxide and water or alcohol at temperatures in the range of 40 DEG to 150 DEG C. in the presence of a metal complex carbonylation catalyst to produce alpha -(p-isobutylphenyl)propionic acid or its alkyl ester; or (III): reacting said p-isobutylstyrene with carbon monoxide and hydrogen at temperatures in the range of 40 DEG to 150 DEG C. in the presence of a metal complex carbonylation catalyst to produce alpha -(p-isobutylphenyl)propionaldehyde and then oxidizing said alpha -(p-isobutylphenyl)propionaldehyde to produce alpha -(p-isobutylphenyl)propionic acid. The recovered isobutylene is recycled to produce 1,1-bis(p-isobutylphenyl)ethane by reaction with acetaldehyde in the presence of sulfuric acid.