Complex sentence: Sulfonation by chlorosulfonic acid gives the "ortho" and "para" substituted chlorosulfonic acids, which are converted to the sulfonamide with ammonia.
Split into simpler sentences: Sulfonation by chlorosulfonic acid gives the "ortho" and "para" substituted chlorosulfonic acids. The "ortho" isomer is separated and converted to the sulfonamide with ammonia.