Complex sentence: Diethyl dithiophosphoric acid is chlorinated to generate diethylthiophosphoryl chloride, which is then treated with sodium 4-nitrophenolate (the sodium salt of 4-nitrophenol).
Split into simpler sentences: Diethyl dithiophosphoric acid is chlorinated to generate diethylthiophosphoryl chloride. The diethyl dithiophosphoric acid is then treated with sodium 4-nitrophenolate (the sodium salt of 4-nitrophenol).