3,4-dihydroxybenzoic acid is not only organic acid, but also organic compounds that naturally exist in flue-cured tobacco, burley tobacco, and Oriental flue-cured tobacco. Its molecular formula is C7H6O4, molecular weight is 154.12, CAS number is 99-50-3, and its appearance is white to light brown needle-like crystals. Soluble in hot water, ethanol, and ether, but slightly soluble in cold water, insoluble in benzene, not only can occur in boiling water decomposition but also can release carbon dioxide.
Vanillin and piperaldehyde can be used as raw materials to prepare 3,4-dihydroxybenzoic acid. Using vanillin as raw material, 3,4-dihydroxybenzoic acid was obtained by alkali melt oxidation and acidification after demethylation. Using piperaldehyde as raw material, piperic acid was obtained by oxidation with potassium permanganate, and 3,4-dihydroxybenzoic acid was obtained by hydrolysis with aluminum trichloride.
It is understood that at present 3,4-dihydroxybenzoic acid is mainly used as dye intermediates, pharmaceutical intermediates, and analytical reagents in the coating, medicine, the chemical industry, biology, and other fields. We in the storage of 3,4-dihydroxybenzoic acid should avoid contact with strong oxidants, and alkalis, shall not be mixed with oxidants, acid storage, transportation, need to be stored in a cool, dry, ventilated special warehouse room, away from fire, and heat sources, should also be equipped with the corresponding leak container, explosion-proof light and ventilation facilities.
