204 COMPONENTS OF ESSENTIAL OILS 



Salicyl aldehyde, C rt H 4 (OH)(COH), an oily liquid of specific 

 gravity 1*172, boiling at 196, occurs in oil of spircea and in other 

 oils. 



Anisic aldehyde, C,.H 4 (OCH 3 )(COH), occurs in oils of anise and 

 fennel. It boils at 248. 



Cinnamic aldehyde, C 6 H 5 (CH:CH.COH), is the chief constituent 

 of oils of cassia and cinnamon. It boils at 247. 



A Jcetone, carvone (or carvol), C 10 H 14 O, occurs in oils of caraway 

 and dill. It is isomeric with carvacrol. It boils at 225 and has a 

 specific gravity of 0'962. Its constitution is probably 



C.CH 



HC CO 

 HC CH, 



C.C 3 H 7 



Acids derived from benzene occurring in essential oils, chiefly in 

 the form of esters, are benzoic acid, C G H 5 COOH ; salicylic acid, C (i H 4 

 (OH)(COOH); and cinnamic acid, C, 5 H 5 .CH:CH.COOH. Methyl 

 salicylate, C 6 H 4 (OH) COOCH 3 , boiling at 226 and of specific gravity 

 1-20, is the main constituent of the oils of winter-green and birch. 



4. Aliphatic or Open Chain Compounds. A large number of 

 compounds falling under this heading have been found in various es- 

 sential oils. Foremost among these may be placed geraniol, C 10 H I8 0, 

 which is probably (CH 3 ) 2 C:CH.CH 2 .CH 2 C.(CH 3 ):CH.CH 2 OH, linalol 

 an isomeric body, probably 



CH 3 .C(CH,):CH.CH 2 .CH 2 .C(CH 3 )(OH).CH:CH 2 

 and Nerol, another isomer, probably 



CH 3 .C.CH.,.CH ( ,.CH:C(CH 3 ) 2 



II 

 HC.CH 2 OH 



the stereo-isomer of geraniol. 



These three bodies are alcohols ; derived from them are the alde- 

 hydes a-citral (geranial or geranaldehyde) 



CH 3 .C.CH 2 .CH 2 .CH:C(CH 3 ), 



II 

 OHC.C.H 



and fB-citral (neral) 



CH 3 .C.CH 2 .CH.,.CH:C(CH 3 ) 2 



II 

 H.C.CHO 



Another alcohol, citroneilol, C 10 H 20 O, and its aldehyde, citronellal, 

 C 10 H 18 O, are also important constituents of many sweet-scented es- 

 sential oils. 



