METHOD OF SEPARATION OF VANILLIN AND SYRINGALDEHYDE Russian patent published in 1997 - IPC

FIELD: chemical technology, organic synthesis. SUBSTANCE: invention relates to the synthesis of vanillin (4-hydroxy-3-methoxybenzaldehyde) and syringaldehyde (4-hydroxy-3,5-dimethoxybenzaldehyde). Vanillin and syringaldehyde were separated by mixture dissolving in potash solution (100-400 g/l) at 60-100 C and potassium syringate is precipitated at 20-40 C and potassium vanillate - at 0-20 C. The obtained precipitate of syringate and vanillate is dissolved in water and vanillin and syringaldehyde were precipitated by acidification with carbon dioxide gas. Yield of vanillin and syringaldehyde is up to 96% of initial and content of the second component is less 0.5%. Potash and carbon dioxide gas were regenerated from the potassium hydrocarbonate solutions by heating up to 80-100 C. EFFECT: excluding toxic methanol, ammonia, improved separation of products without reagent consumption.