PROCESS FOR THE PREPARATION OF 1-OXO-1,3-DIHYDRO-5-ISOBENZOFURANCARBOXYLIC ACID AND ITS USE FOR THE PRODUCTION OF CITALOPRAM

摘要

In the process of preparing 1-oxo-1,3-dihydro-isobenzofuran-5-carboxylic acid (A), terephthalic acid (I) and formaldehyde (I) are added to the fuming sulfuric acid containing at least 20% by weight of sulfur trioxide. heat and then isolate the final product. HE