A fixative is used to equalize the

vapor pressure Vapor pressure (or vapour pressure in English-speaking countries other than the US; see spelling differences) or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phase ...

s, and thus the volatilities, of the raw materials in a

perfume Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. ...

oil, as well as to increase the tenacity. Fixatives can be resinoids ( benzoin, labdanum,

myrrh Myrrh (; from Semitic, but see '' § Etymology'') is a gum-resin extracted from a number of small, thorny tree species of the genus '' Commiphora''. Myrrh resin has been used throughout history as a perfume, incense and medicine. Myrrh mix ...

olibanum Frankincense (also known as olibanum) is an aromatic resin used in incense and perfumes, obtained from trees of the genus ''Boswellia'' in the family Burseraceae. The word is from Old French ('high-quality incense'). There are several species o ...

storax Storax ( la, storax; el, στύραξ, ''stúrax''), often commercially sold as styrax, is a natural resin isolated from the wounded bark of '' Liquidambar orientalis'' Mill. (Asia Minor) and ''Liquidambar styraciflua'' L. (Central America) ( H ...

, tolu balsam) or the molecules ambroxide, civetone and

muscone Muscone is an organic compound that is the primary contributor to the odor of musk. The chemical structure of muscone was first elucidated by Leopold Ružička. It consists of a 15-membered ring ketone with one methyl substituent in the 3-positi ...

, which were originally obtained from animals, but can and are now mostly synthesized because it is more economical, more consistent and more ethical (animals were either killed or are kept in captivity to collect the secretions from their perineal glands). Synthetic fixatives include substances of low volatility ( diphenylmethane, dipropylene glycol (DPG),

cyclopentadecanolide Cyclopentadecanolide is a natural macrolide lactone and a synthetic musk. Natural occurrence Cyclopentadecanolide occurs in small quantities in angelica root essential oil and is responsible for its musklike odor. Production Cyclopentadeca ...

, ambroxide, benzyl salicylate) and virtually odorless

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

s with very low vapor pressures ( benzyl benzoate, diethyl phthalate, triethyl citrate).

References

Perfume ingredients {{Chem-stub