Aldehydes

Group: Chemical Components

According to a general definition of Aldehyde that says:

"An aldehyde is an organic compound containing a terminal carbonyl group. This functional group, called an aldehyde group, consists of a carbon atom bonded to a hydrogen atom with a single covalent bond and an oxygen atom with a double bond. Thus the chemical formula for an aldehyde functional group is -CH=O, and the general formula for an aldehyde is R-CH=O. The aldehyde group is occasionally called the formyl or methanoyl group. Other classes of organic compounds containing carbonyl groups include ketones and carboxylic acids." wikipedia

As of Ketones, they generally smell pleasant and they are frequently used in perfumes and also in food flavouring.

Coming back to aldehydes, they are formed by partial oxidation of primary alcohols and form carboxylic acids when they are further oxidized. Whereas, secondary alcohols oxidize to give ketones. Aldehydes also vary in smell. Low molecular weight aldehydes, e.g., formaldehyde and acetaldehyde, have sharp, unpleasant odors; higher molecular weight aldehydes, e.g., benzaldehyde and furfural, have pleasant, often flowery odors and are found in the essential oils of certain plants. Aldehydes are used for the manufacture of synthetic resins, e.g. bakelite, and for making dyestuffs, flavorings, perfumes, and other chemicals. Some are used as preservatives and disinfectants.

Examples of ALDEHYDES:

Methanal (characteristic pungent odor)
Ethanal (occurs in nature and produced)
Propanal (fruity odor)
Butanal (acrid smell)
Benzaldehyde (almond-like odor)
Cinnamaldehyde (cinnamon odor)
Tolualdehyde (4-Methylbenzaldehyde)

Perfumes using aldehydes may be floral, fruity or citrus in nature. Fatty aldehydes contain long chains of carbon atoms connected to an aldehyde group. They have 8-13 carbon atoms in their molecular formula. The fatty aldehydes have a very pleasant odor, with a fruity or a floral scent, and can be detected in very low concentrations.

Fresh floral aldehyde adds the impression of fresh breezes and flowers like jasmine, rose, iris and lily of the valley. Because of these characteristics, the fatty aldehydes are used in the formulation of many perfumes. They are also added to soaps and detergents to give them their "fresh lemon scent."

Green floral aldehydes give perfumes sharper notes and aromas of the outdoors. The result is a fragrance with the scent of green grass and plants. While Woody floral aldehyde adds the scents of cedar, patchouli, oak and other wooden tones that suggest warmth.

The aromatic aldehydes have a benzene or phenyl ring connected to the aldehyde group. The aromatic aldehyde molecules have very complex structures but are probably the easiest to identify. Benzaldehyde is an example which is the simplest aromatic aldehyde consisting of Benzene ring with a formyl substituent and has pleasant almond-like odor. Cinnamaldehyde/ 3-phenyl-2-propenal is of complex structure that gives cinnamon note. Vanillin/4- hydroxy-3-methoxy-benzaldehyde is used as vanilla note, an ubiquitous note in almost all fragrances. Anisaldehyde or anisic aldehyde is widely used for its good tenacity. It is the main component for numerous floral accords like lilac, hawthorn, anise, honeysuckle etc.

Most widely used aldehydes in perfumery are C7 (possessing a herbaceous green aroma), C8 (octanal, orange-like), C9 (smelling of roses), C10 (decanal, powerfully evocative of orange rind), Citral, a complex 10-carbon aldehyde (fragrance of lemons), C11 (undecanal, “clean” aldehydic, naturally present in coriander leaf oil~also used is unsaturated C11 undecen-1-al), C12 (the odor of lilacs or violets), C13 (waxy, with grapefruit tone)and the C14 (evoking the scent of peach-skin).

SOME ALDEHYDIC FRAGRANCES:

Apres L'Ondee (1906), is said to be the First Fragrance to use Anisic Aldehyde.
Before Chanel No. 5, which is said to be the first modern aldehydic fragrance developed by Ernest Beaux in 1921 and officially launched in 1922 for sale. Coco Chanel had commisseioned him to create something with modern innovations and he came up with aldehydes. But before that, fragrance houses like L.T Piver and Houbignat had been successfully producing fragrances with aldehydes.

Chanel No. 5 (and later, No. 22) used a bouquet of aliphatic - or "fatty" - aldehydes (C10, C11, and C12) that together combine to produce a crisp citrus-and-floral note, with a pronounced soapy tone.

You might also like to try some of the popular aldehydic fragrances: Lanvin Arpege, Jean Patou Joy,Ivoire de Balmain, Chloe, Yves Saint Laurent Rive Gauche, Elizabeth Taylor White Diamonds, Givenchy Ysatis, Dior Miss Dior, Estee Lauder Knowing, Guerlain Vol de Nuit, Avon Rare Gold, Joop! Femme, Tommy Hilfiger True Star, Givenchy L'Interdit, Agent Provocateur Maîtresse, Dolce & Gabbana Classique, and Lagerfeld Femme.