The biggest divide between natural and synthetic fragrances lies in the way they are created.
The Solvent Extraction is performed by putting plants into big, rotating drums. The plants are then covered with petroleum ether or benzene. The plant parts eventually dissolve in whatever solvent is used. This leaves a waxy substance that contains the oils. This substance is then placed in ethyl alcohol. The oil dissolves in the alcohol, which is then burned off, leaving a highly concentrated perfume oil. The solvents that are used along with the preservatives in synthetic fragrances are considered chemicals of concern and this is not disclosed to the consumer as the label claim is simply ‘fragrance’. There is no standard for production in the fragrance industry in terms of what solvents can be used.
The International Fragrance Association (IFRA) has a standard by which manufactures must follow in order to call their fragrances natural. The standard requires that aromatics are made by physically extracting the volatile fractions from plants WITHOUT chemically altering them. Natural aromatic raw materials must be physically obtained from plants using distillation, expression and extraction. Synthetically reconstituted essential oils, synthetic nature-identical ingredients and intentionally chemically modified natural raw materials (e.g. chemical acetylation of essential oil) cannot be used in fragrance compounds that are described as being natural.” If you’d like to read more, I explain the “rules” that we follow when formulating with fragrances.