
180 HIGH PERFORMANCE POLYMERS
chloride, are no longer present in the reaction mixture,
since the free sulfonic acid causes deactivation of the
catalyst, and thionyl chloride and sulfur chlorides like-
wise lead to undesirable byproducts. A further diffi-
culty is that N,N-dimethylformamide is required for
complete conversion of chlorobenzenesulfonic acid
with thionyl chloride into the corresponding sulfonyl
chloride, carcinogenic N,N-dimethylcarbamoyl chlo-
ride being formed as a byproduct [19].
Another synthesis route for bis-(4-chlorophenyl)-
sulfone is the reaction of chlorobenzene and
chlorobenzenesulfonic acid. At 220–260
◦
Catan
elevated pressure of