Hedione® HC (dsm-firmenich) – High-Cis Methyl Dihydrojasmonate

Hedione® HC – dsm-firmenich

Hedione® HC is the same methyl dihydrojasmonate (CAS 24851-98-7) as classic Hedione – but with a different ratio of the four stereoisomers. Only one of them, the (+)-cis isomer, carries virtually all of the odor. In classic Hedione it makes up around 10%; in Hedione HC, considerably more. Hence the strength, the longer tenacity and the lower dosage range.

Odor Profile

• “A unique powerful, floral note reminiscent of magnolia blossoms.” (official manufacturer description) – a powerful floral note reminiscent of magnolia blossoms
• Official descriptors: Floral, Jasmine, Citrus
• Top and heart note
• Odor threshold of the (+)-cis isomer: 15 ppb. For comparison: the strongest of the three remaining isomers sits 16 times higher (240 ppb), the weakest around 1000 times higher (Werkhoff et al., Food Reviews International, 2002)
• Tenacity on the blotter: about 1 month (classic Hedione: about 2 weeks)
• Physical form: pale straw-colored to yellowish oily liquid

Role in the Formula

The strength of Hedione HC is not a marketing claim but a direct consequence of chemistry: one isomer outstrips the other three in odor intensity by orders of magnitude, and HC contains a higher share of it. Accordingly, less material is needed for the same or a stronger effect: 7–25% versus 12–38% for classic Hedione® in fine fragrance.

The professional assessment is more nuanced than the marketing. Perfumer Arcadi Boix Camps describes Hedione HC in the trade journal Perfumer & Flavorist (2004) as “good” but “less pleasurable” than classic Hedione, which he describes as “flowing, flying, diffusing with charm and grace.” Pure strength, then, is not the same as pure quality – the material is worth testing in your own formula, not just judging by dosage numbers.

Why pH Matters

The manufacturer's condition of a neutral pH (5.5–7.0) is a direct consequence of the same chemistry that gives Hedione HC its strength. The cis isomer is thermodynamically less stable than the trans isomer and, in the presence of a base, rapidly converts to the weaker trans form – already documented in the 1971 cis-enrichment patent, where complete conversion is achieved by refluxing for two hours in alkaline sodium methoxide solution. Hedione HC is therefore unsuitable for soap and strongly alkaline bases: there, the expensive cis form epimerizes back, and the invested strength is lost.

Use in Perfumery

• Fine fragrance: 7–25% (classic Hedione: 12–38%)
• Shampoo: 0.8–4%
• Shower gel: 2–10%
• Candles: 2–5%
• Only for bases with pH 5.5–7.0; not for soap or alkaline media

Practical Notes: Dissolving, Storage, Pairing

Dissolving: Liquid and directly dosable; soluble in oils and ethanol, only very sparingly soluble in water.

Storage: Cool, dry, protected from light and tightly closed.

Pairing: Jasmine, white flowers, magnolia, citrus top notes. In the trade literature, Hedione is also traditionally paired with musk materials, whose diffusion it enhances. Not for soap or other alkaline bases.

The Race for One Isomer

Cis-enrichment was not first patented by Firmenich but by a competitor: in 1971 the French company Roure Bertrand Fils et Justin Dupont (later part of Givaudan) obtained a patent on methyl dihydrojasmonate with at least 90% cis content, made by hydrogenation in the presence of an aluminium catalyst. Firmenich responded with its own cis-enriched qualities, and in the 1990s Zeon (Cepionate) joined this race with another approach. The manufacturer does not publish the exact cis content of Hedione HC.

The pinnacle of this development is Paradisone: a nearly pure (+)-cis isomer, produced by asymmetric hydrogenation on a ruthenium catalyst (Firmenich patent, Dobbs, Vanhessche, Rautenstrauch et al., Angewandte Chemie, 2000). Paradisone is a Firmenich captive material and is not available on the open market. The full story of this race is on our encyclopedia page Hedione® HC: The Race for One Isomer.

Safety Information

According to the RIFM assessment (Api et al., Food and Chemical Toxicology, 2015), the material is not sensitizing, not genotoxic and not phototoxic; the NOAEL for repeated dosing is 100 mg/kg/day with a margin of exposure (MOE) of 256. No IFRA Standard exists for CAS 24851-98-7. It is not on the allergen list under Annex III of the EU Cosmetics Regulation. According to the manufacturer's data it is not classified as hazardous.

Physico-Chemical Properties

FAQ

How does Hedione® HC differ from classic Hedione®?
Same CAS number, but a higher share of the odor-active (+)-cis isomer. This gives more strength, about 1 month of tenacity on the blotter instead of 2 weeks, and a lower dosage range (7–25% instead of 12–38% in fine fragrance). Classic Hedione® is available here in the shop.

How do I dose Hedione® HC?
7–25% of the formula in fine fragrance; 2–10% in shower gel, 0.8–4% in shampoo, 2–5% in candles.

Why does pH matter?
In an alkaline environment the cis isomer converts to the weaker trans form – the same reaction once used deliberately to remove cis impurities. In soap, the effect is therefore lost.

How does Hedione® HC differ from Paradisone?
Both are cis-enriched variants of the same molecule. Paradisone is nearly isomerically pure but a Firmenich captive material and not for sale. Hedione HC is the strongest Hedione grade available on the open market.

Is Hedione® HC hazardous, or are there IFRA limits?
No. The RIFM assessment confirms the material is not sensitizing; no IFRA Standard exists.

Hazard Information (CLP Labeling)

Important Notice

This product is a perfumery raw material intended exclusively for fragrance development, creative experimentation, education and the study of perfumery materials.

It is not a finished cosmetic product.

Please use responsibly.