It is an important intermediate in the synthesis of antipyretic and analgesic drugs. It is a white to quasi-white crystalline powder with melting point of 96 ~ 100℃.
Obtained by bromination and hydrolysis of phenol. Heat phthalein to 140-145℃, bromine reaction, control the inlet speed, so that the reaction tail gas basically no bromine vapor discharge. After bromine removal, the residual hydrogen bromide was removed by carbon dioxide and decompression at 120℃ chemical book. The reactants were hydrolyzed with water for 0.5h in boiling water bath. O-carboxyl benzaldehyde was precipitated after cooling. Yield of 60%.