Vanillin

Chemical Properties

Colorless to pale yellow liquid with lemon, citronella, and rose aroma. Exists in three optical isomers: d-, l-, and dl-. D-Citronellal is abundant in essential oils and is a major component of citronella oil and eucalyptus oil, with a boiling point of 203–204°C, relative density (d₄²⁰) 0.8510, optical rotation [α]D¹⁸ +10°18′, and refractive index (D²⁰) 1.4467. L-Citronellal is found in lemongrass oil, with a boiling point of 206°C, relative density (d₂₅²⁵) 0.8567, refractive index (nD²⁰) 1.4491, and optical rotation [α]D -3°. It readily cyclizes to form menthol in acidic media. Flash point 77°C. Soluble in ethanol and most non-volatile oils, slightly soluble in volatile oils and propylene glycol, and insoluble in glycerol.

Uses

GB2760—96 stipulates it as an approved edible flavoring agent. Primarily used in formulating citrus and cherry-type flavors.

Uses

Mainly used as a raw material for synthesizing citronellol, hydroxycitronellal, menthol, etc. It can be used in small quantities in low-grade lemon, cologne, magnolia, lily-of-the-valley, honey, and fern-type fragrances, primarily for its prominent grassy-green note effect.