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The general steps for the synthesis of 2,3-difluorobenzaldehyde from 2,3-difluorotoluene are as follows: (1) Preparation of the device: connect the tubular reactor as shown in Fig. 2, and choose a combination of pipes with (3a + 3c) DC channels and inclined square pancake-type variable diameter flat pipes. Determine the pipe diameter and volume according to the experimental needs. (2) Solution preparation: 6.06 g of cobalt acetate and 6.06 g of sodium molybdate were dissolved in 200 mL of acetic acid containing 200 mg of 2,3-difluorotoluene to form a mixed solution, ensuring that n (cobalt acetate): n (2,3-difluorotoluene) = 0.015:1. Meanwhile, 6.06 g of sodium bromide was dissolved in 35% H2O2 to prepare a H2O2-acetic acid solution, adjusting n (sodium bromide): n(2,3-difluorotoluene) = 0.015: 1. (3) Reaction process: 2,3-difluorotoluene-acetic acid solution and H2O2-acetic acid solution were injected into a continuous heat exchanger tubular reactor through a constant-flow pump at a flow rate of 5.56 ml/min and 11.11 ml/min, respectively, to ensure that n(H2O2): n(2,3-difluorotoluene) = 2:1. The reaction was carried out in a microchannel reactor with a set reaction temperature of 120 °C and a residence time of 1500 s. (4) Post-treatment: after completion of the reaction, the outlet material was cooled and the reaction was quenched with dichloromethane. The conversion of 2,3-difluorotoluene was determined to be 65.1% and the yield of 2,3-difluorobenzaldehyde was 48.2% by GC analysis.