Patent ID: 7858381
Filing Date: 2010-12-28
Classification: C07C,Y10T

Abstract:
1. A process for preparing high-purity, halogen-free o-phthalaldehyde, which comprises: a) hydrolyzing tetrahalo-o-xylene at a temperature of 155-160° C. and a pressure of from 2 to 5 bar, optionally in the presence of a phase-transfer catalyst, to o-phthalaldehyde, b) converting the o-phthalaldehyde in an acidic alcoholic solution at a temperature of from 0 to the reflux temperature into the corresponding dialkoxyphthalane and, subsequently, c) cleaving acetals by acid hydrolysis at a pH between 1.5 to 7, resulting in high-purity, halogen-free o-phthalaldehyde.