4-Cyanobenzoic acid (30.00 g, 203.90 mmol) was added to thionyl chloride (29.11 g, 244.68 mmol) in batches under magnetic stirring. Subsequently, three drops of N,N-dimethylformamide (DMF) were added to the reaction system as a catalyst. The reaction mixture was heated to reflux with continuous stirring for 1.5 h. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the solution was distilled at 235 °C to afford the white solid product p-cyanobenzoyl chloride in 98% yield (5.50 g) with a melting point of 67.2-68.2 °C. The structure of the product was confirmed by the following characterization data: 1H NMR (600 MHz, DMSO-d6) δ 8.06 (d, J = 7.8 Hz, 2H), 7.96 (d, J = 7.8 Hz, 2H); 13C NMR (151 MHz, DMSO-d6) δ 165.9, 134.7, 132.6, 129.9, 118.1, 115.1; IR (KBr, νmax/cm-1)3101, 3051, 2229, 1772, 1739, 1597, 1401, 1287, 1211, 1167, 896, 851, 634; high-resolution mass spectrometry (HR-MS, ESI) m/z: [M + H]+ calculated value C8H4ClNO + H+ 166.0053, measured value 166.0054.
