Method for preparing formylaryl phosphonate by dehydrogenation coupling of aromatic aldehyde and H-phosphonate

The invention discloses a method for preparing formylaryl phosphonate by dehydrogenation coupling of aromatic aldehyde and H-phosphonate. The method comprises the following steps: dissolving Ag2O and K2S2O8 in a mixed solution of CH3CN/H2O, adding to a mixed solution of dialkyl phosphonate and aromatic aldehyde, and reacting under stirring for 1.5 hours at 95-105 DEG C to obtain a reactant, wherein the molar ratio of dialkyl phosphonate to aromatic aldehyde is (1.8-2.2): 1, the molar ratio of Ag2O to aromatic aldehyde is 4.5%-5.5% and the molar ratio of K2S2O8 to aromatic aldehyde is (1.8-2.2): 1; filtering the reactant to obtain a filtrate and filter residue; washing the filter residue with ethyl acetate to obtain a washing liquid; mixing the filtrate and the washing liquid, concentrating to obtain a concentrate and separating the concentrate by column chromatography to obtain formylaryl phosphonate.