4Hydroxy3methoxybenzaldehyde

4-hydroxy-3-methoxybenzaldehyde, commonly known as vanillin, is an aromatic aldehyde that provides the characteristic flavor and aroma of vanilla. Its molecular formula is C8H8O3, and its structure features a benzene ring with a hydroxyl group at the 4-position and a methoxy group at the 3-position, in addition to an aldehyde substituent.

Vanillin occurs naturally in the cured seed pods of vanilla orchids, especially Vanilla planifolia. It is the primary flavor component of vanilla bean extract and is present in smaller amounts in other plants and foods. Beyond natural sources, vanillin is widely produced synthetically or semi-synthetically for commercial use.

In terms of properties, vanillin is a white to pale yellow crystalline solid with a sweet, creamy vanilla odor. It is soluble in alcohols and organic solvents and only moderately soluble in water. The molecule contains both a phenolic hydroxy group and an aldehyde function, which influence its reactivity, including potential oxidation to vanillic acid under certain conditions.

Production methods for commercially used vanillin are predominantly synthetic. It is commonly manufactured from guaiacol or lignin-derived precursors, involving catalytic oxidation and formylation steps, or produced via biotechnological routes using engineered microorganisms. A smaller portion is obtained by direct extraction from vanilla pods.

Uses of vanillin span flavoring agents for foods and beverages and fragrance ingredients for cosmetics and perfumes. It is subject to regulatory purity standards in many jurisdictions, often with separate considerations for related compounds like ethyl vanillin that can alter flavor profiles. Overall, vanillin remains one of the most widely used vanilla flavor compounds worldwide.