Hydrochloric Acid → 4-(Hydrazinocarbonyl)benzoic acid

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Reaction Steps

In 1 l of methanol was dissolved 180 g of monomethyl terephthalate, and the solution was slowly added dropwise to 500 ml of hydrazine hydrate (50%) at room temperature while stirring. After the drop-wise addition, the mixture was heat-refluxed for 5 hours while stirring. A hydrochloric acid aqueous solution was slowly added to the reaction mixture to adjust to a pH of about 1 to thereby precipitate white crystals. Two liters of water was added to the system, followed by stirring for a while. The formed crystals were collected by filtration under reduced pressure, washed twice with 200 ml of water, and dried to obtain 160 g of p-carboxybenzhydrazide (melting point: 235-236° C.).

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