Isoeugenol

Uses in perfumery :

Isoeugenol is used in carnation, spicy and ambery notes, often combined with Eugenol. Often replaced by Acetyl-Isoeugenol, unregulated.

Year of discovery :

Data not available.

Natural availability :

In many cases, naturally present Isoeugenol is accompanied by Eugenol, which is present in greater quantities in the following raw materials. Isoeugenol can be extracted from Clove Bud EO (1%), betel leaf (about 10%) or Ylang-Ylang Extra EO, or other fractions (up to 0.5% depending on the fractions).

Isomerism :

Isoeugenol has two diastereomers with a similar smell. It is the mixture of these two isomers that is the most used in perfumery. The trans isomer is nevertheless the most present in this mixture, as it is thermodynamically more stable. Eugenol is an isomer of Isoeugenol, as the double bond present in the two molecules is simply relocated from one molecule to another. Its smell is less fruity but more woody and vanillic. Styrallyl acetate and Frambinone® are examples of constitutional isomers of Isoeugenol. Their smell is however very different.

Synthesis precursor :

Isoeugenol is a precursor to the synthesis of several compounds of olfactory interest. Catalytic hydrogenation of the molecule allows to obtain Dihydoeugenol. In the past, Vanillin was produced by an oxidation reaction on Isoeugenol. The alcohol function of the molecule can finally be used for several esterification reactions, to obtain Isoeugenyl acetate for example.

Synthesis route :

Isoeugenol can be produced from Eugenol. Forming sodium or potassium salts from Eugenol allows to isomerize the molecule by heating it in order to obtain Isoeugenol by an acid treatment. This isomerization can also be obtained directly by a ruthenium or rhodium catalysis.

Stability :

Becomes red under the effect of light. This raw material is not convenient in every functional base : can't be used in a candle or shower gel base.

Other comments :

Isoeugenol is one of the 26 allergens in perfumery.
Smokier and more rounded than Eugenol, but less floral and metallic. Slightly more expensive than Eugenol.

Allergens :

This ingredient is classified as an allergen under European Regulation 2023/1545, dated August 26, 2023.
Its presence must therefore be declared on product labels when it exceeds 0.001% in leave-on products and 0.01% in rinse-off products.
Oral care products can contain up to 0.003% of isoeugenol before labelling becomes mandatory

Signal word :

Warning

Hazard pictograms :

Precautionary statements :

IFRA 51^th :

This ingredient is restricted by the 51th amendment

Quantitative limit on the use :

Annexe I :

Some regulated synthetic ingredients are found in nature and in certain proportions in natural ingredients. This presence in nature has to be taken into account when calculating limits of use recommended by the IFRA. In case you do not know these concentrations, you can use the ones estimated by the IFRA. Here they are :

Disclaimer :

ScenTree is solely responsible for the information provided here.

To learn more about IFRA's standards : https://ifrafragrance.org/safe-use/library