134-20-3

26638-43-7

2-Methoxycarbonylbenzenesulfonyl chloride was synthesized by a continuous flow reaction system using methyl o-aminobenzoate as starting material. The system configuration consisted of two tubular reactors: the first reactor (20 m long, 15 mm diameter) and the second reactor (40 m long, 10 mm diameter, filled with 3 mm diameter copper spheres). The reaction materials included 1587 g of methyl o-aminobenzoate (35 wt% hydrochloric acid solution containing 1916 g of hydrogen chloride), 6720 g of 30 wt% sodium nitrite solution (containing 2016 g of sodium nitrite), 6825 g of saturated sodium bisulfite solution (containing 2730 g of sodium bisulfite), and 7936 g of methylene chloride. The operating steps are as follows: 1. the first tubular reactor was maintained at 80 °C through a heat exchanger, and 20 wt% hydrochloric acid, 40 wt% sodium nitrite solution, and methyl o-aminobenzoate were continuously transported by three metering pumps at a flow rate ratio of 1:5:3, respectively, to the first mixer, and after mixing, they were fed into the first reactor for diazotization reaction with a residence time of 100 s. The reaction solution was collected in the fourth storage tank. 2. the saturated sodium bisulfite solution and methylene chloride are stored in the fifth storage tank, respectively, and transported to the second mixer through the fourth and fifth metering pumps with the diazotization reaction solution in the ratio of methyl o-aminobenzoate to sodium bisulfite molar ratio of 1:2.5, and the ratio of flow rate of methyl o-aminobenzoate to methylene chloride flow rate of 1:5. 3. the mixed solution was reacted in the second reactor at 100°C for a residence time of 90 seconds. 4. Upon completion of the reaction, the reaction solution was collected for 2 minutes (equivalent to an amount of 624 g of methyl phthalate), transferred to a receiver tank for layering, separation of the organic layer, evaporation of methylene chloride and drying to give 910 g of 2-methoxycarbonylbenzenesulfonyl chloride in 94% yield.