Cinnamyl alcohol

Description

Occupational cases of contact dermatitis were reported in the perfurne industry. Patch tests can also be positive in food handlers. Cinnamic alcohol is contained in the "fragrance mix".

Chemical properties

Cinnamyl alcohol can exist in (Z)-[4510-34-3] and (E)-[4407-36-7] forms. Although both isomers occur in nature, the (E)-isomer is far more abundant and is present, for example, in styrax oil. (E)-Cinnamyl alcohol is a colorless, crystalline solid with a hyacinth-like balsamic odor.
Cinnamyl alcohol can be dehydrogenated to give cinnamaldehyde and oxidized to give cinnamic acid. Hydrogenation yields 3-phenylpropanol and/or 3-cyclohexylpropanol. Reaction with carboxylic acids or carboxylic acid derivatives results in the formation of cinnamyl esters, some of which are used as fragrance materials.

Chemical properties

Cinnamyl alcohol has a pleasant, floral odor and bitter taste.

Occurrence

Occurring as an ester or in the free state in hyacinth, Aristolochia clematis, Xanthorrhoea hastilis and in the essence of daffodil flowers. It is also reported found in guava fruit and peel, lemon peel oil, cassia leaf, Bourbon vanilla and cinnamon bark, leaf and root.

The Uses of Cinnamyl alcohol

Cinnamyl alcohol was used to study the alkylation of 2,4-di-tert-butylphenol by cinnamyl alcohol using aluminum-containing mesoporous ethane-silica catalyst. It was used to study gold nanoparticles supported on titanium dioxide catalysed oxidative coupling of alcohols and amines to form the corresponding imines.

What are the applications of Application

Cinnamyl alcohol is mainly used in the following fields:
(1) Used as a flavouring or flavouring agent in cosmetics;
(2) Used as a deodorant in perfumes;
(3) Intermediates in organic synthesis;
(4) Allergic epidermal patch test.

Definition

ChEBI: A primary alcohol comprising an allyl core with a hydroxy substituent at the 1-position and a phenyl substituent at the 3-position (geometry of the C2C bond unspecified).

Preparation

By reduction of cinnamic aldehyde.

Aroma threshold values

Detection: 1 ppm; cis- form, 81 ppb; trans- form, 2.8 ppm

Taste threshold values

Taste characteristics at 20 ppm: green, floral, spicy and honey with a fermented yeasty nuance.

Synthesis Reference(s)

Chemistry Letters, 5, p. 581, 1976
The Journal of Organic Chemistry, 59, p. 6378, 1994 DOI: 10.1021/jo00100a046
Tetrahedron Letters, 34, p. 257, 1993 DOI: 10.1016/S0040-4039(00)60561-0

Flammability and Explosibility

Not classified

Contact allergens

Cinnamyl alcohol occurs (in esterified form) in storax, Myroxylon pereirae, cinnamon leaves, and hyacinth oil. It is obtained by the alkaline hydrolysis of storax and prepared synthetically by reducing cinnamal diacetate with iron filings and acetic acid, and from cinnamaldehyde by Meerwein-Ponndorf reduction with aluminum isopropoxide. Cinnamyl alcohol is contained in the “fragrance mix.” As a fragrance allergen, it has to be mentioned by name in cosmetics within the EU. Occupational cases of contact dermatitis were reported in perfume industry. Patch tests can be positive in food handlers.

Synthesis

Obtained originally by saponification of extraction from storax; synthetically, by reduction of cinnamaldehyde with sodium or potassium hydroxide.

Purification Methods

Crystallise the alcohol from diethyl ether/pentane. [Beilstein 6 I 281.]

Hazard

Cinnamyl alcohol is potentially skin sensitising and may cause symptoms such as redness, bumpiness or itching of the skin. A patch test screening several groups of perfumed materials was performed on 20 subjects sensitised to the perfume. The most common allergen was cinnamyl alcohol (15 out of 20).