The general procedure for the synthesis of 2-phenylenedi(meth)iminoethane sulfonyl chloride from phthalic anhydride and taurine is as follows:1. A suspension of taurine (8.0 g, 63.9 mmol) and potassium acetate (6.7 g, 68.3 mmol) was refluxed in acetic acid for 15 min. 2. Phthalic anhydride (10.1 g, 68.4 mmol) was added, and the reaction was continued to be refluxed for 3 h. 3. Upon completion of the reaction, the reaction was cooled to room temperature, the solid product was collected by filtration, washed with cold acetic acid and dried under vacuum at 100 °C to give a white solid.4. The above white solid (14.3 g, 54.7 mmol) was suspended in toluene (50 ml), and phosphorus pentachloride (8.12 g, 39.0 mmol) was added under the protection of nitrogen.5. After the reaction mixture was heated and refluxed for 1 hour The reaction mixture was heated and refluxed for 1 hour, then phosphorus pentachloride (8.12 g, 39.0 mmol) was added again and refluxing was continued for another 2.5 hours.6 Upon completion of the reaction, a brownish solution was poured from a small amount of the solid formed, and the solution was subsequently concentrated under vacuum.7 The concentrated residue was poured into a mixture of ice and water (ice:water=50:50, 100 ml), and the solid product was filtered to collect the solid product.8 Finally, the solid was dried under vacuum at 45°C for 16 hours to obtain a light brown color.9 The reaction was carried out under nitrogen protection. Vacuum dried for 16 hours to give a light brown solid product (6.4 g, 34% yield).
