What Is Trans-2-Hexenyl Butyrate?
Trans-2-Hexenyl Butyrate is an ester that chemists first isolated and documented in the early 1960s, when advances in gas chromatography let researchers identify minor trace compounds in fruit. Today it is produced on an industrial scale by reacting trans-2-hexenol with butyric acid under controlled heat and pressure, followed by purification to achieve a material that is more than 95 percent pure.
Although small amounts occur naturally in apples, pears and several green leaves, virtually all commercial supply comes from this controlled synthetic route. Synthesis guarantees consistent quality, steady availability and easier compliance with safety regulations.
At room temperature the ingredient presents as a clear, colorless liquid with a light, mobile feel similar to a typical plant oil. It is neither thick nor sticky so it pours easily and mixes smoothly with most common fragrance solvents.
Perfumers reach for Trans-2-Hexenyl Butyrate quite often because it lends an instantly recognisable fruit nuance without overpowering a formula. Its manufacturing costs sit on the lower side of the spectrum which keeps it accessible for everyday products as well as fine fragrance work.
The material maintains good stability in finished goods ranging from soaps and shampoos to candles which adds to its popularity among creative and technical teams alike.
What Does Trans-2-Hexenyl Butyrate Smell Like?
Most professionals place this molecule in the fruity family.
On a blotter it opens with the crisp snap of biting into a fresh green apple. A gentle leafy facet rides alongside giving a just-cut grass impression that makes the fruit feel authentic rather than candied. As minutes pass a soft sweetness emerges suggesting pear juice and a faint buttery tone that rounds the edges. The overall impression stays bright ripe and mouth-watering without turning sticky or overly sugary.
In the traditional top, middle and base note framework Trans-2-Hexenyl Butyrate sits firmly in the top note group. Its molecular weight is low and its vapor pressure is high which means it lifts off the skin or fabric quickly to provide an immediate fruit hit that invites the wearer closer.
Projection is moderate. It radiates clearly within the first arm’s length during the opening moments then settles back politely. Longevity is short to medium, often lasting around one to two hours on blotter before fading, so perfumers usually anchor it with longer lasting ingredients to keep the fruit signature alive in the dry-down.
How & Where To Use Trans-2-Hexenyl Butyrate
This is a friendly little molecule that behaves well on the blotter and in the beaker. It pours easily, dissolves quickly in alcohol and standard perfume bases and does not have the stubborn sharpness that can make some green notes tricky to balance.
Perfumers usually place it in the top note to give an instant bite of fresh apple or crushed leaf. It partners beautifully with hexyl acetate, ethyl butyrate and a touch of cis-3-hexenyl acetate when building a crisp green apple accord. Add a trace of ionone for a pear skin effect or blend it with linalool and rose oxide to enliven a dewy floral bouquet. In citrus compositions it lifts grapefruit and lime, while in gourmand styles it sweetens berry or rhubarb without turning them into candy.
You will reach for Trans-2-Hexenyl Butyrate over similar esters when you need more realism and a slight buttery roundness rather than a purely acidic bite. It shines in shampoo bases, airy body mists and laundry softener where gentle fruit freshness is wanted at first sniff but should not linger for hours. In candles it survives the heat and throws well yet stays clean without a waxy off note. One weaker spot is very heavy oriental perfumes where its lightness can be swallowed unless supported by bright aldehydes.
Typical usage sits between 0.05 % and 2 % of the finished fragrance concentrate, though some fine fragrance top accords may climb to 3-5 % if a pronounced apple signature is the goal. At trace levels it reads as leafy green and slightly wine like. Above 1 % it turns sweeter, juicier and the buttery nuance becomes clearer. Pushed too far it can feel oily and overripe so moderation is key.
Prep is minimal. Dilute to 10 % in ethanol or dipropylene glycol for easier weighing and safer evaluation. Because the material is insoluble in water avoid adding it neat to surfactant systems without first premixing in a suitable solvent. No antioxidant is generally required.
Safety Information
Working with any fragrance raw material calls for sensible precautions to keep both the creative and the lab environment safe.
- Always dilute before smelling: create a 10 % or weaker solution in ethanol or dipropylene glycol before evaluating on a blotter
- Never sniff directly from the bottle: headspace inside the container can reach high concentrations that may irritate the nose or respiratory tract
- Ensure good ventilation: blend and weigh in a fume hood or a well-ventilated space to avoid inhaling vapors
- Wear protective gear: nitrile gloves and safety glasses prevent accidental skin or eye contact
- Health considerations: some aroma chemicals can trigger skin irritation or allergic reactions. If you are pregnant or breastfeeding consult a medical professional before prolonged handling. Brief exposure to low concentrations is generally safe but sustained or high-level contact can be harmful
Always consult the latest safety data sheet provided by your supplier and review it regularly as updates occur. Follow current IFRA guidelines for recommended concentration limits to ensure your formulas remain both appealing and safe.
Storage And Disposal
When kept under the right conditions Trans-2-Hexenyl Butyrate stays fresh for roughly two years after purchase. Some users report little change even after three or four years when bottles are stored with extra care. A refrigerator set between 4 °C and 8 °C will slow down oxidation and can add many extra months of life, yet a simple cool dark cupboard away from heaters or sunny windows is usually good enough for day-to-day work.
Air management is the next key point. Transfer the material into the smallest practical bottle so the headspace stays low then top the bottle up as you use it to keep oxygen out. Close products with polycone caps which create a tight seal and resist solvent attack. Dropper bottles look handy but often let vapors escape and fresh air creep in, so save them for short term trials only.
Dilutions need the same attention. Store your 10 % or 1 % solutions in amber glass with polycone inserts and check them every few months for cloudiness or off notes. If the scent feels dull or oily discard the sample and make up a new batch from the neat material.
Always label each container with the full name Trans-2-Hexenyl Butyrate, the date it was bottled, the strength of any dilution and the main safety phrases such as “Insoluble in water” and “Irritant to eyes and skin.” Clear records make later audits and project work far easier.
For disposal never pour neat material down the sink as it can upset local water treatment systems. Small leftover amounts can be soaked into an absorbent pad, sealed in a plastic bag then placed in regular trash if local rules allow. Larger volumes should go to a licensed chemical waste handler. The ester is readily biodegradable in the environment, yet good lab practice still treats it as a potential pollutant until properly broken down.
Summary
Trans-2-Hexenyl Butyrate is a fruity green ester best known for its juicy apple bite with a soft buttery edge. It lifts top notes, freshens florals and sweetens berries so creatives reach for it in everything from shampoo to fine fragrance. The molecule is easy on the budget, stays stable in most bases and blends without fuss, which explains its solid spot on many perfumers’ benches.
Keep an eye on its quick evaporation and short life on skin, cushion it with longer stayers when you need the fruit tone to last and watch the dosage or it can slide into oily territory. Handle it with the same respect you give the rest of your kit, store it cool and tight, and it will reward you with bright realistic freshness in a wide mix of accords. A fun tool that proves small details can make a perfume feel instantly delicious.