*2.3.1.1.4 Soxhlet extraction*

*Essential Oils - Bioactive Compounds, New Perspectives and Applications*

(**Figure 2**) [33].

(**Figure 3**) [33].

*2.3.1.1.3 Solvent extraction*

boiling points ranging from 150 to 300°C can be evaporated at a temperature close to that of water. The steam distillation takes advantage of the volatility of a compound to evaporate when heated with steam and the hydrophobicity of the compound to separate into an oil phase during the condensation process

Also known as liquid–liquid partitioning, its principle is based on the solubility in an organic solvent non-mixable to water. This technique is used on delicate plants to produce higher amounts of EOs at a lower cost. The method is limited by the compound solubility in the specific solvent used, long extraction time, relatively high solvent consumption and often unsatisfactory reproducibility and purity

**78**

**Figure 3.**

**Figure 2.**

*Illustration of liquid–liquid extraction method.*

*Diagrammatic illustration of steam distillation method [32].*

Typically, it is a solid–liquid extraction used when the desired compound has a limited solubility in a solvent and the impurity is insoluble in that solvent. There are several advantages of using this technique. These advantages include:


As disadvantages, it requires several hours or days to be performed; moreover, the sample is diluted in a large volume of solvent.

Due to heating, the thermal degradation and volatilization of components have been observed, and hydrolysis of esters to yield alcohols and carboxylic acids can occur (**Figure 4**) [34].
