(E)-Beta-ionone

Other comments :

Beta-Ionone is more woody than alpha-Ionone, which is fruity and more floral-violet. Gamma-Ionone is quite woody and resinous.
The first use of Beta-Ionone in perfumery was in 1893, in Vera Violetta, by Roger et Gallet.

Stability :

Stable in perfumes and diverse functional bases

Uses in perfumery :

Beta-Ionone is used in violet flower reproductions, in floral and fruity notes (blackcurrant, blackberry). Gives a powdery effect and provides a ''retro '' image to women's perfumes. Provides a floral sweetness. Very good binder. To be combined with Bergamot EO, Hedione® and Beta-Damascone® for a ''tea '' scheme.

Year of discovery :

This discovery was made in 1896, starting from Irones, isolated from orris butter. Ionones were discovered randomly, when a laboratory assistant added sulfuric acid to dishwash a glass containing a wrong intermediary to irone synthesis.

Isomerism :

Beta-Ionone is obtained during the cyclization step of Pseudoionone, using phosphoric acid instead of sulfuric acid, in a catalytic amount. gamma-Ionone is obtained by using boron trifluoride as a catalyst. Alpha-Damascone® and beta-Damascone are positional isomers of Ionones. Their ketone function as well as a methyl group are in different parts of the molecule. Their smell is modified: Damascone® have a smell of cooked apple instead of violet.

Synthesis precursor :

beta-Ionone is a precursor to the synthesis of DihydroBeta-Ionone and Ambrinol (thermolysis reaction).

Natural availability :

Beta-Ionone is present in sweet acacia or Osmanthus Absolute from which it can be extracted in its natural state. In most cases, it is the synthetic beta-Ionone that is used in perfumery.

Synthesis route :

Today, the synthesis of Ionones is made from Citral, by reaction with acetone. The category of compounds obtained is called Pseudoionone. The cyclization of Pseudoionones into Ionones is done in an acid medium. Sulfuric acid is the most preferable acid for synthesizing beta-ionone. The yield of this cyclization is clearly in favor of this isomer. In general, each Ionone synthesis results in the formation of isomers of the desired molecule. In the case of beta-Ionone, a purity of about 92% can be achieved on an industrial scale.