Patent ID: 6686482
Filing Date: 2004-02-03
Classification: C07D

Abstract:
A process for producing piperonal which comprises continuous three steps of:(A) an addition reaction step wherein 1,2-methylenedioxy-benzene and glyoxylic acid are reacted to form 3,4-methylenedioxymandelic acid in the presence of a strong acid, (B) an extraction step wherein an organic solvent is then added to a reaction mixture and the mixture is neutralized with a base to extract 3,4-methylenedioxymandelic acid in an organic solvent layer, and separating the organic solvent layer and an aqueous-layer, and (C) an oxidation reaction step wherein the aqueous layer is removed and the organic solvent layer is concentrated, and then, nitric acid is added to a concentrate, and the 3,4-methylenedioxymandelic acid and nitric acid are reacted to form piperonal.