As week by week the day is getting shorter and it becomes dark outside much earlier I think most of us spend more time at home these days. It also gets colder, the first snow of this winter might fall any moment and Christmas is right behind the corner I though this may be a good opportunity for a chemistry lesson about one of these “warming” ingredients that we “love” in our winter perfumes.
The full name of this compound is (3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyl-2,4,5,5a,7,8,9,9b-octahydro-1H-benzo[e][1]benzofuran but to average perfume user it is known as ambroxan. It’s an aromachemical of molecular weight of 236,39 grams, formulae C16H28O. It belongs to the class of tetranorlabdane oxide and is valued in perfumery.
Ambergris or a grey amber is one of the most expensive raw materials that can be used by perfumers. It is extremely rare as it is obtained from cachalot (sperm whales.) cachalot are currently on the IUNC Red List of Endangered Species and they’re classified as “vulnerable” which means that their species might soon be endangered if their survival and reproduction are threatened. It’s their digestive system (which can be as long as 300 meters) where ambergris is produced. There were times when poachers killed sperm whales and were selling the grey amber.
The boulder of ambergris forms in a cachalot stomach as a result of irritating the delicate intestinal lining of sperm whales. It mostly happens because of squid beaks, this species loves eating squids. The mass is growing bigger, moves farther the digestive system, finally it becomes the indigestible solid that blocks the rectum. As a response the organism increases water absorption in the intestines, eventually the mass of squid beaks turns into a rock.
As the Cachalot continues its life, the rock grows bigger and bigger. Sometimes a whale is able to expel ambergris from its body but sometimes it becomes impossible, the boulder completely blocks the excretory system. It has fatal results, a whale dies. Its monstrous body will become food for sharks and other organisms. At some point the stone of grey amber will be released into the sea. Because its density is smaller than of water, it floats on the waves, and this can happen for decades. At first it’s a solid, viscous matter of grey to black color that has a marine and fecal odor. During its journey before landing on some beach it ages and gains earthy and sweet aroma.
Ambroxan doesn’t occur in natural ambergris. The main ingredient of this material – ambrein can be separated from the grey amber stones by heating them with alcohol and then allowing the solution to cool down. White crystals of ambrein crystallize. The interesting thing is that ambrein is almost odorless. However by a process of oxidation it can break in two, forming molecules of ambrox and ambrinol. These two possess intensive aroma and are main odour component of ambre gris.
Due to sperm whales being a vulnerable species and due to the cost of obtaining this rare perfume material, modern perfumery found a way how to introduce a smell of ambergris into perfume without affecting cachalot population. The chemical equivalent, ambroxan was developed. It’s structure is identical with ambrox derived from ambrein. Nowadays there are many methods to synthesise ambroxan, they’re described in chemical publications.
To mention just a few there are ways starting with compounds such as (-)-drimenol, labdanolic acid, (-)-sclareol. Synthetic ambroxan is used in perfumes to add them a fragrance of musk and it also plays a role of a fixative (it makes a fragrance last longer.) Ambroxan was first obtained via a synthesis pathway in 1950. Ambroxan is a trade name for Henkel, Quest uses it as Amberlyn and Firmenich as Ambrox. Nowadays it’s hard to find a perfume without the addition of this synthetic aroma molecule. There are even a couple of brand which somehow started specializing in using in their perfume creations.
Here’s a list of couple of perfumes containing ambroxan:
- Juliette Has a Gun: Oil Fiction, Anyway, Not a Perfume*
- Escentric Molecules: Escentric 02, Molecule 02*
- Le Labo: Baie Rose 26, Another 13
- Frederic Malle: French Lover, Geranium pour Monsieur
- D&G: Light Blue
For more fascinating information about ambergris read this article.
* – means that a perfume is pure ambroxan in alcohol. Is it still perfume?
Chemist in the Bottle 