What Is Hydroxycitronellal Diethylacetal?
Hydroxycitronellal Diethylacetal is a specialty aroma molecule first noted by perfumers in the late 1950s when chemists explored ways to give classic muguet notes greater stability. It is produced by reacting hydroxycitronellal with ethanol in the presence of an acid catalyst, a step that converts the aldehyde into a diethyl acetal. The starting hydroxycitronellal itself can be sourced from naturally occurring citronellal, yet the overall process happens in a laboratory so the final material is classified as synthetic.
At room temperature it appears as a clear slightly syrupy liquid that ranges from colorless to a faint straw tint. The viscosity is low enough to pour easily but high enough to cling to the side of a glass vial. Because it resists oxidation and keeps its quality over time it has become a workhorse in modern fragrance creation.
Hydroxycitronellal Diethylacetal shows up in fine fragrance, shampoo, shower gel, soap, household cleaners and even scented candles. Its production scale is well established which keeps its price reasonable for most fragrance houses. Formulators appreciate that it folds into both alcohol based perfumes and water based cleaners without much fuss, making it a versatile and widely used ingredient.
What Does Hydroxycitronellal Diethylacetal Smell Like?
Perfumers place this material in the floral family. Off a blotter it opens with a gentle lily of the valley effect that feels fresh and slightly watery, backed by a soft green nuance that keeps the floral tone crisp rather than powdery. There is a mild sweetness reminiscent of morning dew on white petals yet it never turns sugary. The overall impression is clean, light and natural.
In the traditional perfume pyramid scents evolve through top, middle and base notes. Hydroxycitronellal Diethylacetal sits firmly in the middle. It rises within a few minutes of application, bridging bright top notes and deeper base notes by extending the floral theme through the heart of the composition.
Projection is subtle to moderate, giving enough presence to be noticed without overwhelming nearby noses. On a blotter the scent remains detectable for roughly four to six hours, which aligns with its role as a reliable heart note that gracefully bows out once heavier base materials take over.
How & Where To Use Hydroxycitronellal Diethylacetal
To put it plainly this is a friendly material to handle. It pours without fuss, blends easily and does not bite the nose during bench work which makes it a welcome addition to any perfumer’s organ.
Formulators reach for it when they want to anchor a lily of the valley or general white floral heart without the sharp edges that can come from pure hydroxycitronellal. Used on its own it adds a dewy green lift that keeps bouquets feeling lively. In a muguet accord it sits beside small doses of cyclamen aldehyde, citronellol or hedione to extend freshness while rounding out the floral curve.
It also softens harsher jasmine or orange blossom notes and can lighten heavy woody bases. Because the molecule is clean and mild it shines in modern transparent styles, feminine fine fragrance, baby care and fabric softener. It can fade in the background of dense oriental or gourmand blends so in those cases other florals may serve better.
Typical dosage runs from a trace up to about 5 percent of the concentrate. At very low levels it reads as a cool watery green nuance. Push it higher and the full lily impression blooms with a gentle sweetness that can drift toward soapy, a quality many formulators exploit for shower gels and detergents.
The material holds up under moderate heat so it is candle safe yet remember that high wick temperatures will speed evaporation and shorten its life in the burn. In surfactant bases it maintains stability and does not discolor which is a plus for clear shampoos and liquid soaps.
Prep work is minimal. Because the liquid is a touch viscous many labs pre-dilute to 10 percent in ethanol or dipropylene glycol to improve weighing accuracy and speed up blending. No special antioxidants or UV filters are required.
Safety Information
Working with any fragrance raw material calls for sensible precautions and Hydroxycitronellal Diethylacetal is no exception.
- Always dilute before evaluation: prepare a 10 percent or weaker solution before smelling to avoid nasal overload and accidental inhalation of concentrated vapor
- Never smell directly from the bottle: use a scent strip or blotter at arm’s length for a first impression
- Ensure good ventilation: open windows or use a fume hood so airborne molecules do not accumulate in the workspace
- Wear protective gear: gloves prevent skin contact and safety glasses shield eyes from splashes during blending
- Monitor health considerations: some aroma chemicals can trigger irritation or allergy in sensitive individuals, consult a doctor before use if pregnant or breastfeeding and remember that prolonged or high-level exposure can be harmful even when low doses are considered safe
Always consult the most recent Safety Data Sheet supplied by your vendor and recheck it regularly as information may change. Follow the current IFRA guidelines for maximum safe use levels to keep both creators and end users protected.
Storage And Disposal
When kept in a tightly closed bottle at normal room temperature Hydroxycitronellal Diethylacetal usually stays in specification for around two years, sometimes longer. Cooler conditions slow down any loss of quality so a shelf in the refrigerator can extend life well past that point, provided the bottle is brought back to room temperature before opening to avoid moisture condensation.
If fridge space is limited a cool dry cupboard away from direct sunlight, radiators or hot equipment is still fine. Light and heat speed up oxidation which dulls the floral tone so darkness and steady temperatures are your best allies.
For both the neat material and any dilutions choose bottles with polycone caps. These flexible liners create a snug seal that keeps oxygen out and fragrance in. Dropper caps let air slip past the threads and should be avoided. Try to decant into the smallest practical bottle so the headspace stays minimal because a half empty bottle exposes a lot of surface area to air.
Label every container clearly with the chemical name date of transfer and any hazard symbols from the Safety Data Sheet. A neat label saves guesswork months later and helps anyone else in the lab stay safe.
Spills are rare thanks to the syrupy texture but wipe any drips with paper towel then wash the area with warm soapy water. Small leftover amounts can usually go down the sink with plenty of running water unless local rules say otherwise. Larger volumes should be collected in a dedicated waste drum and handed to a licensed disposal service. The molecule breaks down in the environment over time yet concentrated discharge is never good practice so err on the side of caution.
Summary
Hydroxycitronellal Diethylacetal is a lab made twist on a classic floral note that swaps the sharper edges of hydroxycitronellal for a smoother lily of the valley effect. It smells fresh green and mildly sweet making it perfect for shampoo, soap, fabric care and light feminine perfumes.
Perfumers like it because it blends easily lifts a bouquet without shouting and costs less than many specialty florals. It is happy in transparent modern styles but can also soften stronger white flower accords or add a clean touch to woody blends.
The molecule is stable, not too pricey and simple to handle so it often finds a permanent slot on the fragrance bench. Keep an eye on air exposure during storage and remember that very heavy oriental or gourmand bases may push it into the background. Other than that it is a fun tool with plenty of creative range.