Citronellol Aroma Chemical
CAS# 106-22-9

Citronellol, whose chemical name is 3,7-Dimethyl-6-octen-1-ol, is a clear, colorless, oil-based liquid material. It is sometimes referred to as Rhodinol, although commercial Rhodinol is actually a mixture of Citronellol and Geraniol obtained from geranium essential oil. This material exists in two main stereoisomeric forms: (−)-Citronellol, associated with rose and known for a more airy, elegant scent, and (+)-Citronellol, associated with lemongrass and perceived as more intense. Commercial products are typically racemic mixtures or pure (−)-Citronellol. In terms of sourcing, Citronellol can be obtained naturally from rose, geranium, and lemongrass essential oils, or produced synthetically by hydrogenating citronellal (from lemongrass oil) or pinene (from turpentine) to ensure large-scale output and stable pricing. Historically, this material is linked to early essential-oil distillation practices, and its chemical structure was isolated in the late 19th century by terpene pioneers Tiemann and Schmidt. Identifying Citronellol as a key contributor to the smell of rose helped lay the groundwork for the first artificial reconstructions of rose in perfumery.

Description

Olfactorily, this substance belongs to the floral family with a fresh, slightly citrusy nuance. It strongly evokes fresh rose petals-clean, waxy, lightly green, with a gentle lemon-like facet-creating a natural “dewy” impression that contrasts with the warmer sweetness or fruit-leaning profile of Geraniol. Working mainly in the heart (mid) note with medium intensity, Citronellol diffuses softly yet remains clearly recognizable. Its substantivity is medium to moderately high: more tenacious than many citrus materials, but more volatile than woody notes. In formulation, it functions as an odor modifier and an indispensable backbone for virtually any rose accord, and it is also widely used in geranium, lily-of-the-valley, and other white-floral themes. It can freshen heavy florals, soften harshness, and add body to citrus structures. One of the most classic pairings is blending Citronellol + Geraniol + Phenylethyl Alcohol (PEA)-a trio that can shape core rose nuances ranging from powdery pink rose to deep velvety rose to dried rose effects depending on the ratio. In addition, when combined with Citral, it yields a natural, fresh lemon character often used in dishwashing fragrances or lemon flavor-like profiles. Because it is a convenient liquid to handle, perfumers often use Citronellol neat, though it also dissolves very well in alcohol and organic solvents.

Applications

Citronellol has very broad applications, from women’s floral perfumes and men’s fougère styles to personal-care products such as skin creams, shower gels, and shampoos, thanks to its pleasant odor and good stability. In particular, its ability to withstand alkaline conditions and its strong base-odor masking performance make it a common component in bar soaps, detergents, and dishwashing liquids, alongside a certain degree of insect-repellent effect attributed to its structural similarity to lemongrass-type materials. Usage levels are highly flexible, ranging from 1% to 50% in fragrance compounds, and it can be present at very high proportions in rose-centered perfumes. However, use must comply with IFRA limits, and it is included in the list of 26 allergens that must be declared in Europe (and many other countries) if the concentration exceeds 0.001% in leave-on products and 0.01% in rinse-off products. At high concentrations-or on sensitive skin without antioxidants-Citronellol can cause sensitization, so it should be stored in tightly sealed containers in a cool, dry place, away from light and high temperatures to minimize oxidation. On the market, this material appears in many well-known products such as Chloé Eau de Parfum (a modern, clean, bright rose style), the classic Yardley English Rose, and most rose-scented soaps such as Lux and Camay. Finally, in entry 762 of Perfume and Flavor Chemicals, expert Steffen Arctander described Citronellol as having a fresh rose-like odor with variable tenacity, and emphasized that it is among the most useful materials used in most florals and countless other scents-playing an essential role in recreating rose and geranium essential-oil effects.