China, Europe (note: banned in EU cosmetics since March 2022 per EU Regulation 2021/1902)
Pyramid
Heart/Middle
Cool, dewy, translucent — the ghost of a lily-of-the-valley that never existed in nature. Lilial smells like wet green stems wrapped in tissue paper, with a faint powdery sweetness underneath. The single most consumed muguet aldehyde in perfumery history, now banned in the European Union.
Cool, transparent, green-floral. The immediate impressi on is wet lily stems and crushed cyclamen petals — clean without being soapy, green without being herbal. A faint powdery sweetness sits underneath, closer to linden blossom than to talc. Compared to hydroxycitronellal, which reads rounder and more aldehydic (closer to soap), Lilial is drier and more angular. Compared to Bourgeonal, which is more frankly watery and linear, Lilial has a three-dimensional quality — the green top, the floral heart, and the powdery base operate as distinct phases rather than a single flat note. On fabric, the powdery-sweet quality dominates after hours; on skin, a faintly cum in-like warmth can emerge in the drydown, a characteristic shared with other par a-substituted benzyl aldehydes.
Evolution over time
Immediately
Immediately
Sharp, bright, green-watery. Crushed lily stems and wet cyclamen petals. Cool and transparent, with a faint aldehydic sparkle that lifts immediately.
After a few hours
After a few hours
The green-watery top recedes. A soft, powdery muguet florality takes over — dewy, slightly sweet, with linden-blossom facets. On skin, a faint cumin-like warmth may emerge.
After a few days
After a few days
Quiet, powdery, almost vanillic. The floral structure has largely dissipated. What remains is a clean, slightly sweet, fabric-like residue — the smell of freshly washed linen.
The Full Story
Lilial (CAS 80-54-6, MW 204.31 g/mol, C₁₄H₂₀O) is a synthetic aromatic aldehyde — systematic name 2-(4-tert-butylbenzyl)propanal, also known as p-BMHCA, Lysmeral, or lily aldehyde. Colorless to pale yellow oily liquid, bp 250–251°C at 760 mmHg, flash point 99°C, specific gravity 0.942–0.947 at 25°C. First evaluated by perfumers in 1946, patented in 1956, and commercially available from the late 1950s onward. For over sixty years it was the most consumed muguet odorant in the global fragrance industry.
The molecule is sold as a racemic mixture of (R) and (S) enantiomers. Only the (R)-form carries the characteristic muguet odor — fresh, green, dewy lily-of-the-valley with cyclamen and linden qualities. The (S)-enantiomer is essentially non-odorous. This means the commercial product operates at roughly half its theoretical olfactory potential, a fact that underlines the extraordinary potency of the active isomer.
Odor Character
Clean, watery, green-floral. Lilial smells like lily-of-the-valley stems crushed between wet fingers — transparent, cool, with a powdery cyclamen sweetness that develops on the drydown. Compared to hydroxycitronellal (rounder, more aldehydic, soapier), Lilial is sharper and greener. Compared to Bourgeonal (more watery, linear, one-dimensional), Lilial has greater complexity and a softer fadeout. The odor substantivity of 236 hours at 100% on blotter gives it unusual persistence for a heart-note material.
Synthesis
Industrial production follows a two-step route: crossed aldol condensation of 4-tert-butylbenzaldehyde with propionaldehyde under basic conditions (NaOH, ethanol, 0–5°C), yielding the α,β-unsaturated intermediate 4-tert-butyl-α-methylcinnamaldehyde at >85% yield, followed by selective catalytic hydrogenation (Pd/C, 3 atm, room temperature) to saturate the olefinic double bond while preserving the aldehyde carbonyl. Lilial also occurs naturally in trace amounts in tomato (Solanum lycopersicum) and crow-dipper (Pinellia ternata), though all commercial material is synthetic.
Regulatory Status
Banned in the European Union since 1 March 2022 under Regulation (EU) 2021/1902 (Omnibus IV). Classified CMR 1B (presumed toxic for reproduction) based on animal studies. Added to ECHA’s Substances of Very High Concern (SVHC) list in 2021. The EU ban applies to all cosmetic products; products already on shelves had to be withdrawn. The molecule remains permitted in the United States, Middle East, and most Asian markets. IFRA’s 51st Amendment (June 2023) restricts but does not prohibit use outside EU jurisdictions. The ban forced the reformulation of an estimated twenty thousand consumer products across the European market.
This note in Première Peau. Nuit Elastique. Sample all seven extraits in the Discovery Set.
Did You Know?
Did you know?
Lilial was first evaluated by perfumers in June 1946 but rejected as redundant — too similar to hydroxycitronellal and cyclamen aldehyde, which were deemed sufficient. A researcher named Carpenter kept resubmitting it for olfactory evaluation over the following decade. A patent was finally filed in June 1956, ten years after the initial rejection. Lilial went on to become the single most consumed muguet odorant in perfumery history, present in an estimated twenty thousand consumer products at the time of its EU ban in 2022.
Extraction & Chemistry
Extraction method: Fully synthetic. Two-step industrial route: (1) Crossed aldol condensation of 4-tert-butylbenzaldehyde with propionaldehyde under dilute NaOH (1–5 mol%) in ethanol at 0–5 degrees C, yielding the intermediate alpha,beta-unsaturated aldehyde 4-tert-butyl-alpha-methylcinnamaldehyde at >85% yield. The aromatic aldehyde's lack of alpha-hydrogens favours the crossed product. (2) Selective catalytic hydrogenation of the olefinic double bond using Pd/C (5%) at 3 atm and room temperature, or noble metal catalysts (Pd, Rh on alumina), delivering >95% conversion with >98% selectivity to the saturated aldehyde while preserving the carbonyl group. Industrial variants use continuous flow reactors with MgO/alumina for condensation at 80–100 degrees C and Ni or Cu-chromite for hydrogenation at 100–150 degrees C under 10–20 atm. The product is sold as a racemic mixture of (R) and (S) enantiomers. Product form: colorless to pale yellow clear oily liquid.
Molecular Formula
C₁₄H₂₀O (2-(4-tert-Butylbenzyl)propionaldehyde)
CAS Number
80-54-6
Botanical Name
N/A (synthetic molecule)
IFRA Status
BANNED in EU since March 1, 2022. Still permitted in US, Middle East, Asia. IFRA Amendment 51 restricts but does not ban.
Heart-note floralizer, green-floral diffuser, muguet backbone. Lilial was the dominant muguet aldehyde in contemporary use for over sixty years — consumed in greater volume and value than all other lily-of-the-valley molecules combined, including hydroxycitronellal, cyclamen aldehyde, Bourgeonal, and Lyral. It provided a clean, dewy florality with green-cyclamen lift that functioned as a universal freshness amplifier in both fine fragrance and functional products (detergents, fabric softeners, shampoos). At 0.5–3% of a formul a, Lilial added luminous, wet-green radiance to floral hearts without heaviness. At higher doses (5–10%), it became the subject: a transparent, almost aquatic muguet that read as cleanliness itself. The molecule's unique contributi on was its combinati on of high diffusiveness with moderate tenacity — it projected outward from skin or fabric for hours, then faded gracefully to a soft, powdery residue. Only the (R)-enantiomer carries the characteristic muguet odor. The (S)-form is essentially non-odorous — meaning the commercial racemic mixture operates at roughly half its theoretical olfactory potential. None replicate Lilial exactly. The industry consensus is that Lilial's specific combinati on of green-floral transparency, powdery drydown, and cost-efficiency has no single replacement — reformulations typically require blends of three to five substitutes to approximate the original effect.
