Anisaldehyde

The French name for anisaldehyde 'Aubépine' is revealing the fragrance character of this substance. In French it is called aubépine, also being the French word for hawthorn. Indeed anisaldehyde does smell quite alike the blossom of the hawthorn tree. For that reason is is a must-use material in hawthorn compositions, but it is also very usable in many fresh blossom fragrances like lilac, acacia and in smaller amounts is several other florals, in which it gives some natural freshness.

There are three isomers of anisaldehyde: ortho, meta and para. In fragrance para-anisaldehyde (or p-anisaldehyde) is the most common, or at least a mixture of isomers in which the para isomer dominates. So in fragrances para-anisaldehyde and anisaldehyde are in general the same fragrance material. Other names include 4-anisaldehyde, 4-methoxybenzaldehyde and p-methoxybenzaldehyde.

Drawback is the relatively short shelf life of anisaldehyde, when it gets cloudy quite some anisaldehyde is turned in anisic acid. Anisic acid is not hazardous, but instead of the fresh floral fragrance of anisaldehyde it has an animalic, even fecal scent that renders the anisaldehyde unusable for the most common uses. I recommend not to use it when it turned even slightly cloudy, and use a good antioxidant in compounds that contain anisaldehyde.