Alpha Ionone (Toco)

• 📐 Iupac name: (E)-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one

• 🏭 Manufacturer — IFF

• 🔎 Cas Number — 127-41-3

• 👃 Odor Profile — Warm, woody, balsamic, and floral aroma that is deeply sweet and moderately tenacious. Its resemblance to the odor of violet flowers is legendary.

• 👅 Flavor Profile — At lower concentrations, it has a relatively powerful, sweet-woody taste with a fruity note. Higher concentrations (ex 20 ppm and above) tend to be "perfumey", slightly bitter, and overly woody-floral.

• 🔎 Fema N° 2594

• ⚗️ Uses — widely used in perfume compositions of almost all types. The use in rose bases is very common and generally well-liked, and smaller amounts of ionone are used in woody, herbaceous, floral, balsamic, piney, or citrus-like fragrances. It is often part of a highly desirable complex that displays "powdery" undertones in a fragrance (S. Arctander).

Perfume - fragrance and flavor ingredient with tocopherol addition to preserve the product from oxidation.

In the realm of perfumery, certain ingredients possess the power to evoke a sense of magic and allure. Among these is Alpha-Ionone, a captivating organic compound renowned for its delicate and enchanting fragrance. From its discovery in the late 19th century to its prominent role in perfumes today, alpha-ionone has left an indelible mark on the world of scent. Let us then embark in an odorous, flowery journey in trying to unravel the shroud of mystique surrounding the history and myth around Alpha-Ionone.

Ionone: Between Myth and History

Ionone, the word coined in the 19th century to refer to odorous Citral-derived compounds, originated from the merging of the Greek word ἴον or ion (violet) and “ketone”. This term has found wide use in the field of chemistry and perfumery, drawing inspiration from a profound mythological bedrock.

In the realm of mythology, the story of Ionone traces back to the Roman poet Ovid and his renowned work “The Metamorphoses”, written around the 8th century AD. Within its pages, Ovid narrated the story of a woman called Io, whose extraordinary beauty ensnared the heart of Zeus, the king of the gods of Olympus. The deep enamourment in which Zeus fell, lead him to defy his spouse. Hera, goddess of marriage and women, protector of women during childbirth, and jealous consort of Zeus learned about the relationship between the two, and in retaliation transformed Io into a heifer, a graceful yet captive creature, in an attempt to keep the lovers apart. Io, now trapped in her bovine form, wept, shedding tears of anguish and longing. Zeus, moved by her sorrow, used his powers to transform her tears into delicate, sweet, and fragrant violets that only she was permitted to eat.

Another version of the myth slightly alters the events, attributing to Zeus the transformation of Io into a cow as a means to shield Io from the ensuing wrath of Hera. After the arduous task, Zeus entrusted the earth with the creation of a beautiful flower with a delicate and sweet fragrance, allowing his lover to pasture. In her memory, and being one of the most beautiful flowers ever sprouted, Zeus called them Ion, directly embodying the renewal of spring, and the trials and tribulations of love.

While the mythologic portion of Ionone’s history may have concluded, its history has barely begun. During the second portion of the 19th century, Germany established itself as a prominent propelling force in the field of science, launching the so-called era of “dye chemistry” (Farbstoffchemie) thanks to August Wilhelm von Hofmann. As discussed in this previous article, in 1874, Wilhelm Haarman and Ferdinand Tiemann, one of Hofmann’s students, succeeded in synthetizing vanillin for the first time, thus commencing the “flavor chemistry” (Geschmackstoff-Chemie). Around 1886 Paul Krüger, employer at Harmann and Reimer, a flavor and fragrances factory in Holzminden, Germany, joined forces with Ferdinand Tiemann, scientific adviser and co-founder and silent partner of the Harmann and Reimer. An exstensive period of research brought the two to publish a handful of joint publications, among which it is possible to observe some seminal papers concerning the “scent of violets” (Veilchenaroma) and the separation of ionon and iron.

After seven long and less than commercially lucrative years spent on research, Friedrich-Wilhelm Semmler, a terpene specialist, was brought on board. The research effort of the three culminated in the development of a feasible approach to obtain a good amount of violet scent that will be discussed later. Thus, in 1893 the first synthesis of Alpha-Ionone and Beta-Ionone were successfully developed as proven by the patent released on April 25th of the same year by the Imperial Patent Office (Kaiserliches Patentamt) for the synthesis of a molecule named Ionon-Veilchenduft.

During the same year Henri Roger employed both Alpha-Ionone and Beta-Ionone in a new fragrance called ‘Vera Violetta’ by Roger & Gallet. Before the synthesis of the ionone, Roger tried to create a convincing perfume though the use of only natural ingredients, but the end result demonstrated to be less then optimal. With the advent of the aforementioned ionone, Roger decided to substitute the natural ingredients of the newly patented molecule, creating a more satisfying and multifaceted fragrance with both fresh violet and woody scent, combined with orris-like notes.

In 1904, François Coty was ready to present to the world his first creation ‘La Rose Jacqueminot’. Coty, that many consider the mastermind that forever transformed perfumery from a mere outline into a pure work of art, used two synthetic bases to complement his Rose Absolute, one of which was Alpha-Ionone.

From its mythological etymology to its synthesis in the late 19th century, to a current mass production of around five million pounds per year, this compound has left an indelible mark on the world of scent that continues to deepen with each passing year. Thanks to its extremely recognizable violet notes and adaptability, the mellow scent of Alpha-Ionone has rightfully earned its place among many well-affirmed fragrances such as Chanel No. 5, Tom Ford Black Orchid, Dior Fahrenheit, and many more and the world of perfumery as a whole. Alpha-Ionone remains a cherished ingredient that adds a touch of melancholy, magic, and allure to the scents we wear.

Description and Olfactory Profile

Alpha-Ionone is a ketone, a class of organic compounds characterized by the presence of a carbonyl group (a chemical unit formed by carbon, and by an oxygen atom connected by a double bond), while the remaining two bonds are represented by other carbon atoms or hydrocarbon radicals. Ketones can be found in several sugars and in compounds for medical use, including synthetic and steroid hormones.

• 👃 Odor Profile — Warm, woody, balsamic, and floral aroma that is deeply sweet and moderately tenacious. Its resemblance to the odor of violet flowers is legendary.

• 👅 Flavor Profile — At lower concentrations, it has a relatively powerful, sweet-woody taste with a fruity note. Higher concentrations (ex 20 ppm and above) tend to be "perfumey", slightly bitter, and overly woody-floral.

• ⚗️ Uses — widely used in perfume compositions of almost all types. The use in rose bases is very common and generally well-liked, and smaller amounts of ionone are used in woody, herbaceous, floral, balsamic, piney, or citrus-like fragrances. It is often part of a highly desirable complex that displays "powdery" undertones in a fragrance (S. Arctander).

The synthetization method implemented by Tiemann, Krüger, and Semmler in 1893 involves the condensation of Citral, (also known as 3,7-dimethyl-2,6-octadienal) a pale yellow aldehyde with a strong lemon odor, with Acetone (di-methyl-ketone). The condensation of Citral would lead to the creation of an intermediate substance (a midway substance obtained through the means of a chemical reaction, creating a stepping stone between the chemical reaction and the desired end result or product) known as Pseudoionone. By using an acidic medium, preferably Phosphoric Acid, the Pseudoionone will then be cyclized, resulting in the creation of the desired molecule. Although this has been recognized as the standard method for the synthesis of Alpha-Ionone, various other methodically studied variations exist to tailor the final products according to specific needs.

Alpha-Ionone can also be of natural derivation, falling in the macro-family of Sesquiterpenoids which are a class of immensely diverse natural products built from three isoprene units. Alpha-Ionone can be naturally produced by plants such as Chromolaena Odorata, Swertia Japonica and many more, and it can also be found in baker’s yeast under the name of Saccharomyces Cerevisiae. The natural presence of Alpha-Ionone has also been observed in Burley Tobacco, tea, and whiskey, donating peculiar olfactory and flavory characteristics similar to warm violet, raspberry, woody, floral and sage aromas.

The synthetized Alpha-Ionone aspect may range in gradation from colorless, to pale-straw colored, to a pale, yellowish color liquid. The compound exhibits a distinctive violet-like smell with accompanying woody, balsamic, sweet and floral notes, also often displaying peculiar “powdery” undertones. In higher concentrations the floral olfactory profile of the compound may become overpowering, developing a slightly bitter undertone. When it comes to the major olfactory difference between the naturally achievable Alpha-Ionone and its synthetized counterpart, the only thing that distinguishes them, rendering them applicable in different fields, is the potency of the odor. In fact, the natural molecule will have a more subtle olfactory presence if compared to the higher purity and stronger scent of the synthetized one.

Alpha-Ionone’s olfactory profile makes it one of the most sought-after compounds in perfumery. Its mellow floral smell offers the perfumers the opportunity to use the compound as a base note for more flower-oriented fragrances, as an enhancer, although in smaller quantities, enriching and invigorating other base notes such as rose, pine, balsamic, citrus, herbaceous, freesia and more. Therefore, the compound has been used for years since its synthesis for perfumery modification, including blending, floralizing, mellowing, and more, thanks to its versatile nature.

Alpha-Ionone can also be used in flavor compositions, valued for its characteristic flavor and versatility as a complementary or enhancing aromatic component. It can be utilized to imitate flavors such as blackberry, raspberry, cherry, and loganberry. In addition to its specified functions, it can be employed in spice blends, citrus flavors, vanilla imitations, floral flavors, and as a flavoring agent in chewing gum. Another unique application of Alpha-Ionone has been reported in certain types of licorice candies.

Sources:

• Veilchenduft, Actopic Olfactory Receptors and Endogenous Volatile Compounds: Who was Paul Krüger (1859-1916)? - G. A. Petroianu

• The Synthesis of Ionones. Utilizing the Sole Solid NaOH as the Catalyst for the Condensation of Citral with Acetone - Libor Cerveny, Antonin Marhoul and Lenka Zoubkova, Institute of Chemical Technology

• A Smelling Trip into the Past: The Influence of Synthetic Materials on the History of Perfumery - Patricia de Nicola

• Natural Products Structural Diversity-I Secondary Metabolites: Organization and Biosynthesis - Joe Chappell, Robert M. Coates

• https://www.perfumerflavorist.com/flavor/ingredients/news/21883490/natural-advantage-9886-natural-advantages-warm-and-woody-alpha-ionone

• http://lmrnaturals.iff.com/en/scent/fragrance-ingredients/online-compendium-new/meth-ionone-alpha-extra

• http://lmrnaturals.iff.com/en/site-services/flavor-online-compendium-iframe/natural-alpha-ionone

• https://magazine.x115.it/x115/alpha-isomethyl-ionone-uso-nei-cosmetici/

• https://pubchem.ncbi.nlm.nih.gov/compound/alpha-Ionone

• https://www.sylvaine-delacourte.com/en/blog/ionones-violet-notes

• https://www.perfumersworld.com/view.php?pro_id=3IF00237