What Is Citronellyl Butyrate?
Citronellyl butyrate is an ester that pairs the alcohol citronellol with butyric acid, giving perfumers a stable and versatile building block. First noted in fragrance literature during the late 1930s, it quickly found its way into commercial formulas thanks to its friendly performance in soaps and detergents.
Most of the material on the market is produced through a straightforward acid-catalyzed reaction that combines purified citronellol with food-grade butyric acid. Both starting materials can be sourced from natural feedstocks such as citronella oil or synthesized at scale, so the finished ester is classed as nature-identical even though it is usually made in a factory setting for consistency and cost control.
At room temperature the ingredient appears as a clear colorless liquid with a light viscosity similar to vegetable oil. It pours easily and shows no visible crystallization, which makes handling simple during compounding. Because the production route is well established and relies on abundant raw materials, citronellyl butyrate sits in the lower price bracket of aroma chemicals, allowing generous inclusion levels without inflating a formula’s budget.
You will encounter it frequently in personal care bases where fragrance longevity can be challenged by surfactants. Its good stability toward alkaline media and moderate flashpoint make it a reliable choice for soaps, shampoos and household cleaners, while candle makers appreciate its clean burn behavior. Overall, this is a workhorse material that sees widespread use across both fine fragrance and functional products.
What Does Citronellyl Butyrate Smell Like?
Perfumers slot citronellyl butyrate into the fruity family. Off a blotter it opens with a smooth pear note drizzled in light syrup, quickly joined by a gentle rosy nuance that keeps the fruit from feeling candy-like. The impression is round, fresh and slightly waxy, reminiscent of biting into a ripe yellow pear near a bouquet of garden roses.
The molecule behaves mainly as a middle note. You will notice a brief sparkling lift in the first few minutes, yet its true character settles in the heart where it bridges bright top accords and richer base materials. Expect four to six hours of detectable presence on a blotter under ambient conditions, with projection that is moderate rather than loud. It radiates enough to lend fullness to a composition without overpowering more delicate facets, then fades smoothly into the background instead of clinging tenaciously.
How & Where To Use Citronellyl Butyrate
This is a friendly material to have on the bench, easy to pour and quick to blend without throwing off pH or color. It plays well with most solvents and rarely causes the headaches that stickier esters can bring.
Perfumers reach for it when they need a soft ripe pear or mellow rose tone that stays polite. In a pear accord it can replace part of hexyl acetate to give more body and a slightly floral lift. Layer it with phenethyl alcohol, geraniol or rose oxide and you get a fuller modern rose heart that avoids a vintage feel. It also rounds out apple, melon and tropical fruit mixes by adding a gentle syrupy sheen.
The ingredient shines in functional bases where top notes are stripped out by surfactants. Its fruity warmth survives alkaline soap cure and holds up in detergent wash cycles, so it is a staple for bar soap, liquid hand wash and fabric softener cores. In fine fragrance it sits nicely at 0.2-1 % of the total concentrate as a heart modifier. Functional formulas tolerate higher levels, often 1-3 %, while anything above about 5 % can make the blend feel fatty and overly waxy.
Concentration changes its character. At traces you get a clean rosy freshness that simply rounds the edges. Push it past 1 % and the pear facet blooms and starts to dominate. Beyond 3 % the note thickens, showing a creamy buttery side that can flatten a composition unless balanced with bright top boosters.
No special prep is needed beyond a standard pre-dilution. Because the ester is insoluble in water, pre-mix it into ethanol, dipropylene glycol or your preferred solvent at 10 % before dosing into water-based products. A brief warm roll in the bottle loosens any chilled viscosity on cold days, then you are good to go.
Safety Information
Working with citronellyl butyrate is straightforward but the usual laboratory precautions still apply.
- Always dilute before smelling: Create at least a 10 % solution in a suitable solvent and waft the scent toward your nose rather than sniffing directly.
- Avoid headspace inhalation: Do not smell the raw material straight from the bottle. Cap the container promptly after use to limit vapor buildup.
- Work in a ventilated area: Good airflow removes lingering vapors and minimizes accidental overexposure during weighing or blending.
- Wear gloves and safety glasses: Direct contact can irritate skin and eyes. Nitrile gloves and basic eye protection are usually sufficient.
- Health considerations: Like many aroma chemicals it may trigger irritation or allergic reactions in sensitive individuals. If you are pregnant or breastfeeding consult a healthcare professional before routine handling. Short low-level exposure is generally regarded as safe but prolonged or high-concentration contact should be avoided.
Always review the latest Material Safety Data Sheet supplied with the batch to confirm current hazard ratings, recommended exposure limits and first aid measures. Follow the International Fragrance Association guidelines for maximum dose levels in each product type and check for updates regularly.
Storage And Disposal
When sealed tightly and kept under suitable conditions citronellyl butyrate typically maintains its full olfactory profile for about two to three years. Past that point the fruity rose note can flatten as minor oxidation products build, so a regular sniff test is wise once the material is older than twenty-four months.
Refrigeration is helpful but not essential. A shelf in a cool dark cupboard away from direct sunlight, heaters and hot pipes will keep the ester stable. Sudden temperature swings cause condensation inside bottles, which speeds up hydrolysis, so aim for an even room temperature if you cannot spare fridge space.
Use bottles with polycone caps for both neat material and dilutions. They provide a snug vapor-tight seal that outperforms glass droppers or pipette tops, stopping slow evaporation and the ingress of moist air. Each time you decant, choose a container size that leaves as little headspace as possible because the less oxygen hovering above the liquid the slower it will degrade.
Label every container clearly with the ingredient name, date of opening, dilution strength and any hazard statements from the safety data sheet. Good labeling prevents mix-ups on the bench and helps anyone sharing your workspace understand the risks at a glance.
For disposal, check local regulations first. Small laboratory quantities can often be blended into an absorbent material such as sawdust or cat litter then placed in a sealed bag for municipal waste. Some regions allow highly diluted solutions to be washed down the drain with plenty of running water since the molecule is biodegradable under typical wastewater treatment conditions, though this route should be avoided in septic systems. Large volumes belong at a licensed chemical disposal facility. Never pour neat citronellyl butyrate onto soil or into surface water.
Summary
Citronellyl butyrate is a cost-friendly ester that smells like ripe pear draped over a gentle rose heart and it slips easily into countless accords from apple to melon to modern rose bouquets. Its stability in alkaline bases makes it a go-to for soaps, shampoos and detergents yet it also adds polite fruity warmth in fine fragrance at low percentages.
Creative perfumers enjoy how the material shifts: at traces it is fresh and rosy, at heavier doses it turns creamy and pear-forward. The price point invites experimentation without fear of breaking the budget while the moderate flashpoint and good shelf life simplify handling.
Just remember to store it cool and tightly capped, pre-dilute before adding to water systems and keep an eye on total concentration so the blend does not turn waxy. With those basics covered citronellyl butyrate is a fun reliable building block that earns its popularity on fragrance benches worldwide.