In the intricate world of fragrance composition, hydroxycitronellal stands as a quiet yet indispensable player. This synthetic aromatic compound, while perhaps unfamiliar by name, likely resides in many beloved perfumes, contributing its distinctive fresh, slightly waxy floral character.
From Citronella Oil to Laboratory Creation
Hydroxycitronellal (CAS 107-75-5) owes its origins to citronellal, a naturally occurring compound in citronella oil. However, modern perfumery typically uses synthetically produced hydroxycitronellal rather than natural extraction for several practical reasons:
- Higher purity and consistency in production
- Greater cost-effectiveness
- Reduced environmental impact compared to large-scale plant extraction
The synthesis process involves chemically modifying citronellal to introduce a hydroxyl group (-OH), creating the final compound with its characteristic properties.
A Compound by Many Names
This versatile fragrance ingredient appears under various aliases in different contexts:
- 3,7-Dimethyl-7-hydroxyoctanal
- 7-Hydroxy-3,7-dimethyloctanal
- Citronellal hydrate
- Laurinal
The CAS registry number (107-75-5) serves as the definitive identifier for this compound across all industries and regulatory frameworks.
Sensory Profile and Applications
Hydroxycitronellal delivers a fresh, sweet floral aroma with subtle waxy undertones, making it particularly valuable in:
- Fine fragrances: Often used in floral compositions, particularly lily-of-the-valley accords
- Personal care products: Found in soaps, lotions, and other scented cosmetics
- Household products: Used in detergents and air fresheners for its clean floral character
In fragrance formulations, it typically functions as a middle note, helping bridge brighter top notes with deeper base notes while adding dimensionality to floral bouquets.
Safety Considerations
The Research Institute for Fragrance Materials (RIFM) classifies hydroxycitronellal as a weak skin sensitizer. Key safety findings include:
- A large-scale patch test showed 98.3% of participants experienced no adverse reaction
- The International Fragrance Association (IFRA) has established safe usage levels across product categories
- Individuals with sensitive skin or fragrance allergies may wish to exercise caution
Current industry standards support clear labeling of known sensitizers like hydroxycitronellal to help consumers make informed choices.
Chemical Characteristics
As an aldehyde compound (C 10 H 20 O 2 ), hydroxycitronellal features both an aldehyde group (-CHO) and a hydroxyl group (-OH) in its molecular structure. These functional groups contribute to both its aromatic properties and chemical reactivity.
Responsible Use Recommendations
For those concerned about potential sensitivities:
- Review product ingredient lists carefully
- Conduct patch tests before full application
- Consult dermatologists regarding specific concerns
- Consider products with lower concentrations of floral components if sensitive
When used appropriately within established safety guidelines, hydroxycitronellal continues to serve as a valuable tool for perfumers crafting sophisticated floral fragrances.
