3,4-dihydroxybenzoic acid is a medicinal ingredient, mostly white crystalline powder, some also brown crystals, 3,4-dihydroxybenzoic acid is apt to change color in the air, It has a melting point of about 200 degrees and is soluble in water, ethanol, and ether. It is naturally found in the leaves of the ferns, witchweed, or Holly, and can be obtained after purification.
3,4-dihydroxybenzoic acid is widely used as an important pharmaceutical intermediate and chemical raw material in the pharmaceutical and chemical industries. At present, the international market for protocatechuic acid is in great demand.
As pharmaceutical intermediates, 3,4-dihydroxybenzoic acid is known to have a variety of biological activities, including neuroprotective, analgesic, anti-inflammatory, antibacterial, antioxidant, and anti-tumor properties. To obtain a high yield and purity of 3,4-dihydroxybenzoic acid, 4-hydroxy-3-methoxy benzoic acid can be obtained from vanillin in the presence of organic solvents and oxidation catalysts. Then 4-hydroxy3-methoxy benzoic acid is removed by demethylation reagent to obtain 3,4-dihydroxybenzoic acid. This is a low-cost process to produce 3,4-dihydroxybenzoic acid, which can also be used in industrial production.