Method of preparing terephthalic aldehyde and isophthalic aldehyde

摘要

A method of preparing terephthalic aldehyde or isophthalic aldehyde from p-xylene or m-xylene, which comprises chlorinating the side chain or p or m xylene to a chlorination degree of 2.5 to 3.5, and thereafter contacting the so-chlorinated product with hexamethylenetetramine in aqueous solution at elevated temperature whereby the corresponding aldehyde is obtained.