According to different requirements, essential oils can be further refined into deterpene essential oils, refined essential oils, concentrated essential oils, formulated essential oils and reconstituted essential oils.

1. Deterpene essential oils

Using vacuum fractionation method, selective solvent extraction method or fractional distillation extraction combined method, the monoterpene compound or sesquiterpene compound contained in the essential oil is partially or completely removed.

2. Refined essential oils

Essential oils processed by distillation or vacuum distillation are used to remove some of the essential oils that are unsafe to the human body, have bad odors or contain pigments, and are used to improve their quality.

3. Concentrated essential oils

In order to meet the requirements of the fragrance and intensity of certain essences, vacuum fractionation, or extraction, or preparative chromatography are used to remove the components with no fragrance value in the essential oil.

4. Prepare essential oils

In order to reduce costs or make up for the shortage of natural products, artificial blending methods are used to produce essential oils that are similar to the natural product‘s aroma and other quality requirements.

5. Restructuring essential oils

Use certain methods to remove harmful ingredients, so that the aroma and other quality requirements are similar to those of natural products. This kind of essential oil is called recombinant essential oil.

Plant essential oils can be divided into two categories: single essential oils and compound essential oils according to their ingredients. The single essential oil is a pure essential oil extracted from a plant without any additions, and is usually named after the extracted plant name. Compound essential oil is a mixture of two or more plant essential oils. The coordination between essential oils and essential oils can enhance the efficacy.