The invention discloses a clean production method of oxidizing 3-methoxy-4-hydroxy
mandelic acid for joint production of
vanillin and superfine silver
powder under an alkaline condition by adopting
silver nitrate. The clean production method comprises the following steps: adding a
silver nitrate solution, a 3-methoxy-4-hydroxy
mandelic acid solution and a
sodium hydroxide solution in a parallel flow manner into a reactor, reacting to generate a 3-methoxy-4-hydroxy
acetophenone sodium solution and superfine silver
powder, filtering and separating the generated silver
powder, washing with deionized water and ethyl
alcohol sequentially, and
drying to obtain the superfine silver powder, wherein the reduction yield of the silver powder is 99.4 per cent to 100 per cent; acidizing filter liquor after the silver powder is separated, performing
decarboxylation on 3-methoxy-4-hydroxy
benzoylformic acid to generate the
vanillin, using methylbenzene to extract the
vanillin therein, recycling the methylbenzene
solvent, and performing recrystallization on residues in an
ethanol aqueous solution to obtain the vanillin, wherein the oxidation yield of the methoxy-4-hydroxy
mandelic acid is 95.7 per cent to 98.5 per cent. The
silver nitrate is taken as an
oxidizing agent to prepare the vanillin, so that the oxidation yield is improved, and the oxidation reaction time is shortened. Two practical
fine chemical products can be produced simultaneously, the raw materials can be sufficiently utilized, the generation of waste materials is reduced, the production cost is reduced, and the technological process is safe and environment-friendly.