At first glance, it might seem possible to prepare sulfanilamide from sulfanilic acid by the set of the reactions below: 4-aminobenzenesulfonic acid to (Step 1: using PCl5) 4-aminobenzene-1-sulfonyl chloride to (Step 2: using NH3)4-aminobenzenesulfonamide.
When the reaction is conducted in this way, however, a polymeric product is produced after step 1.
What is the structure of the polymer? Why does p-acetamidobenzenesulfonyl chloride not produce a polymer?