4-Amino-2-methylbenzoic acid

1975-51-5

2486-75-1

GENERAL STEPS: Prior to each experiment, the tubular reaction apparatus was equilibrated by pumping solvent for 30 min at 16 bar hydrogen pressure (see Fig. 4). An Omnifit reaction cartridge (20.0 mm outer diameter, 15.0 mm inner diameter) containing 1 g Pd/C catalyst was used. To prevent overpressurization of the system in case of blockage, the upper pressure of the Knauer pump was set to 25 bar. with the injection ring disconnected from the flow line, the injection ring was opened and manually injected with 3.6 mL of a 0.076 M ethanol solution of 2-methyl-4-nitrobenzoic acid (excess feedstock solution in the ring was recovered for reuse). The injection ring was then closed and plugged into the flow stream. Collect the product at the outlet of the system downstream of the backpressure regulator for 120 min. The solvent is removed by reduced pressure distillation (first using a rotary evaporator and then a secondary rotary vane pump) to give 4-amino-2-methylbenzoic acid.