Estragole aka. Methyl Chavicol Aroma Chemical
CAS# 140-67-0

Estragole, also widely known as Methyl chavicol or p-Allylanisole, is a historically important material with highly interesting chemical characteristics in the fragrance industry. Although its exact year of discovery is not clearly recorded, the name Estragole derives from its abundant presence in tarragon essential oil (estragon). In nature, this compound is also found in basil essential oil and especially in turpentine oil. Notably, much of the Estragole available on the market is not produced through a complex synthetic route, but rather isolated directly from turpentine oil by distillation due to its extremely low cost. However, a higher-yielding chemical method also exists, involving the treatment of turpentine oil in petroleum ether with a solution of mercuric acetate, followed by heating with zinc and sodium hydroxide.

Description

In its physical form, this material appears as a clear to pale yellow liquid and belongs to the herbal odor group with an anise-like olfactory family. The scent of Estragole is sweet and reminiscent of licorice, yet distinguished by a fresher green nuance and a characteristic aromatic quality. As a positional isomer of Anethole, Estragole shows a much greener and leafier character, whereas Anethole tends to be sweeter and more neutral. Functioning as a top to middle note and as an effective modifier, this ingredient has strong odor impact, good diffusion, and a substantivity of around 24 hours on a blotter. In fragrance compositions, it contributes an anise facet together with green tonalities, and is often used at low dosage in masculine fragrances to create a sweet effect at a very economical cost. Perfumers often combine it with lavender, oakmoss, coumarin, and citrus oils to build classical fougère structures. Because of its rather powerful odor, this material should be diluted in safe solvents such as DPG, TEC, or IPM at 10% or 1% for easier dosage control.

Applications

In terms of applications, Estragole was once used frequently in men’s fragrances, scented candles, leave-on cosmetics, rinse-off products, and soaps. Today, however, it is very strictly controlled by IFRA due to scientific reports concerning toxicity and possible genotoxicity, with permitted levels ranging only from 0.01% to 0.2% depending on the product category. Users should pay particular attention to the fact that this is a color-forming material, prone to discoloration over time or in alkaline environments, and it should therefore be stored in tightly sealed containers in a cool, dry place. Many classic masculine fragrance masterpieces once bore the signature of this ingredient before safety regulations became more restrictive. Finally, the value of this material was acknowledged in Perfume and Flavor Chemicals, where Steffen Arctander described Methyl chavicol as having a sweet herbal odor with a pronounced anise character. He praised its role in recreating artificial basil notes and its effectiveness as an excellent modifier in fougère and chypre structures.