What Is Butyl Quinoline Secondary?
Butyl Quinoline Secondary is an aroma molecule belonging to the quinoline family of nitrogen-containing aromatics. First documented for fragrance use in the late 1960s, it was developed to give perfumers a reliable alternative to natural birch tar extracts, which can be difficult to standardise.
The material is produced through a fully synthetic route. A quinoline core is selectively alkylated with a butyl group, then purified by fractional distillation and vacuum stripping. This controlled industrial process keeps quality consistent batch after batch and eliminates trace impurities often found in natural tar distillates.
At room temperature you will see a clear to very slightly yellow liquid with a faint oily sheen. Viscosity sits somewhere between water and glycerine so it pours without too much effort yet clings to glassware long enough for accurate weighing.
Within fragrance labs it is considered a specialist rather than a staple. You will find it most often in chypre, leather and masculine woods where its diffusion and fixative power justify its place on the formula sheet. Despite that performance it is generally classed as mid-priced, making it accessible for fine fragrance as well as functional products when used at low dosages.
What Does Butyl Quinoline Secondary Smell Like?
This ingredient is usually grouped in the leathery family.
On a fresh blotter the very first impression is a supple leather accord reminiscent of new suede jackets. Almost immediately a crisp green edge appears, a little like crushed violet leaves, giving lift to what could otherwise feel heavy. As the minutes pass the profile shifts towards dry woody vetiver nuances then settles into a damp earthy note that anchors the whole effect.
Perfumers classify odours by top, middle and base notes. Tops are light molecules that evaporate within minutes, middles form the character for a few hours and bases linger long after. Butyl Quinoline Secondary sits firmly in the base. Its evaporation curve is slow which allows it to act both as a backbone and a fixative for more volatile ingredients.
Projection is robust without being overwhelming. In an open space the scent radiates a comfortable arm’s length for several hours before moving closer to the skin. Longevity is excellent: on a standard paper blotter the odour remains clearly perceptible for up to six days which explains why only trace amounts are needed in finished compositions.
How & Where To Use Butyl Quinoline Secondary
This is one of those materials that behaves nicely on the blotter and in the beaker. It pours cleanly, does not stain, and does not assault the nose while you weigh it, so most perfumers find it pleasant to handle.
Olfactively it is a leathery base note with woody vetiver undertones, so the first job it tackles is providing depth and persistence to chypre, leather and masculine woody builds. When a formula calls for a smooth suede effect rather than a smoky birch tar feel, this molecule is often the quickest way to get there. It slips neatly into modern oud or dark amber accords as well, rounding rough edges and extending projection without adding obvious sweetness.
Because the scent profile is powerful and tenacious, usage levels usually sit between a trace and 2 percent in fine fragrance concentrates. Going higher, up to 5 percent, is technically possible but only when you want the leather to dominate and the target market can handle a bold statement. At 0.1 percent or below you will mostly notice the green lift and a hint of earthy dryness. Push it past 1 percent and the woody leather facet takes center stage while a faint inky note can appear if the rest of the formula is very transparent.
In functional products such as soap or fabric care the material shines thanks to its excellent stability across a wide pH range and strong substantivity on damp and dry substrates. It survives hot pour soap, holds up in liquid detergents and even cuts through the chlorine note in bleach cleaners. The only place it struggles is in very light aquatic or citrus colognes where its heft can feel out of place.
Prep work is simple: pre dilute to 10 percent in dipropylene glycol or ethanol so dosing stays accurate at low levels and smelling strips do not overload. If you plan on weighing tiny fractions, cool the stock solution to room temperature first as viscosity rises slightly in a warm lab.
Safety Information
Working with any aroma ingredient calls for common sense precautions to protect yourself and those around you.
- Always dilute before evaluation: prepare a 10 percent solution in ethanol or DPG so you can judge the odour without overwhelming your nose
- Avoid direct sniffing: never inhale straight from the bottle, instead fan saturated air toward your nose or use a smelling strip
- Ventilation: blend and evaluate in a well ventilated space to keep airborne concentration low
- Personal protective equipment: wear nitrile gloves and safety glasses to prevent accidental skin contact or splashes to the eyes
- Health considerations: some aroma chemicals can trigger irritation or sensitisation; brief low level exposure is generally safe but higher or repeated doses can be harmful, and anyone pregnant or breastfeeding should seek medical advice before working with this material
Always consult the latest Material Safety Data Sheet supplied by your vendor and review it regularly as updates are frequent. Follow current IFRA guidelines for permitted levels in each product category to keep both creators and end users safe.
Storage And Disposal
When stored with care a sealed drum or bottle of Butyl Quinoline Secondary will keep its full odour strength for roughly three to four years. Many labs push that out to five years by keeping the stock in the fridge but cool room temperature storage is normally fine.
Place the container in a dark cupboard away from radiators, windows and any source of heat. Light and warmth speed up oxidation which can muddy the scent and darken the liquid. Use bottles that fill right to the shoulder so the headspace is small. Topping up with inert gas is ideal but simply keeping the bottle as full as possible already helps.
Choose caps with a polycone liner for both neat material and all dilutions. This cone forms a tight seal that stops slow leaks and keeps air out. Avoid glass dropper bottles since the rubber bulbs breathe and the pipettes let solvent creep up and evaporate.
If you must move the material to smaller bottles label each one clearly with the name, date of filling, dilution strength and the main safety phrases. A quick note such as “leathery base note – wear gloves” saves guesswork later.
Disposal is straightforward but should be done responsibly. The molecule is an aromatic nitrogen compound that breaks down only slowly in the natural environment so never pour it down the sink. Small lab residues can be soaked into paper then placed in a sealed container for hazardous waste collection. Larger volumes belong in an approved chemical waste stream handled by licensed contractors.
Rinse empty bottles with a little solvent, add the rinsings to your waste drum, let the glass air dry then recycle if local rules permit. Always follow regional regulations as they can vary.
Summary
Butyl Quinoline Secondary is a synthetic leathery note with green woody vetiver accents that settles into an earthy base. A tiny dose brings depth, diffusion and long wear to chypres, leather blends and modern masculine woods yet it also pulls its weight in soaps and detergents thanks to rock-solid stability across pH and heat.
It is fun to work with because it plays well in many accords, from suede-soft florals to dark oud fantasies. Performance is high, the price sits in the mid range and the only real caveat is its strong character which can dominate if you push past two percent.
Store it cool, keep the bottles full and cap them tight then you will enjoy years of reliable service from this versatile building block.