3-Methyl-4-nitrobenzoic Acid Preparation Process

In a 200 mL 40% (wt%) H2SO4 solution, add 20 g of Cr2(SO4)3 solid, stir to dissolve, and use as the anode solution; use 80 mL of 10% (wt%) H2SO4 solution as the cathode solution. The electrolytic cell is divided into an anode chamber and a cathode chamber by a ceramic separator. Pour the anode solution into the anode chamber and the cathode solution into the cathode chamber. The anode is a lead dioxide plate, and the cathode is a lead rod. During electrolysis, control the temperature of the electrolyte in the cell at 35°C, cell voltage at 4V, and current density at 500 A/m2. Stop electrolysis when the anode solution changes from dark green to reddish-brown. Then, evaporate the anode solution to obtain 9 g of chromium trioxide red solid, with a yield of 90%. The filtrate (labeled A) is concentrated sulfuric acid containing small amounts of trivalent and hexavalent chromium, which can be recycled for the preparation of the anode solution in the next cycle.

3-Methyl-4-nitrobenzoic Acid Introduction

3-Methyl-4-nitrobenzoic acid is a high-value-added fine chemical product. It can be further synthesized into many important organic products, such as ethyl 4-chloroquinazoline-6-carboxylate, 2-propyl-4-methyl-6-carboxybenzimidazole, methyl 4-methyl-2-ethyl-1H-benzimidazole-6-carboxylate, 3,4-dihydro-4-quinazolinone-6-carboxylic acid, 4-aminophenyl-1,3-dicarboxylic acid, methyl 4-amino-3-methylbenzoate, 4-nitrophenyl-1,3-dicarboxylic acid, etc. Additionally, 3-methyl-4-nitrobenzoic acid is used in pharmaceuticals and is an important intermediate in the synthesis of antihypertensive drugs like Telmisartan and AIDS medications.