VIII] AKOMATIC COMPOUNDS 109 



*' Lavender oil," from Lavandula vera (Labiatae), contains limonene, 

 linalyl acetate, linalol and others. 



" Peppermint oil," from Mentha piper ata (Labiatae), contains menthol, 

 menthyl acetate and others. 



" Clove oil," from Eugenia caryophyllata (Myrtaceae), contains 

 eugenol and caryophyllene. 



" Cinnamon oil," from Cinnamomum zeylanicum (Lauraceae), contains 

 cinnamic aldehyde, eugenol and phellandrene. 



"Lemon oil," from Citrus Limonum (Rutaceae), contains limonene, 

 citronellol and citral. 



" Thyme oil," from Thymus vulgaris (Labiatae), contains thymol and 

 carvacrol. 



"Rose oil," from Rosa centifolia (Rosaceae), contains citronellol, 

 geraniol and others. 



Camphor is a ketone derived from a solid terpene, camphene. The 

 former occurs in the Camphor Tree (Cinnamomum Camphora), a genus 

 of the Lauraceae. 



The resins are oxidation products of the terpenes. They are 

 differentiated into balsams and hard resins. The former consist of resins 

 dissolved in, or mixed with, liquid terpenes, e.g. Canada balsam and crude 

 turpentine. Copal and dammar are examples of hard resins. 



£Ia:pt. 106. Preparation of ^^ clove oil" from cloves (Wester, see p. 10). Cloves 

 are the dried flower-buds of Eiigenia caryophyllata (Myrtaceae). Take 100 gms. of 

 cloves, pound them in a mortar and put the mass into a two litre flask one third full 

 of water. Pass a current of steam through the flask, and collect the distillate cooled 

 by a water condenser. The " essential oil " of Eugenia consists chiefly of the phenol, 

 eugenol, C6H4(OH)(OCH3)CH2CH=CH2, together with small quantities of the 

 terpene, caryophyllene. The latter distills over first, but cannot be isolated unless 

 much larger quantities of material are used. The eugenol settles out as an "oil" at 

 the bottom of the watery distillate. Continue the distillation for four hours, or more, 

 till all the eugenol has distilled over. Then add 25 gms. of sodium chloride for each 

 100 c.c. of the distillate, and shake up the mixture in a separating funnel with small 

 quantities of petrol ether until no more eugenol can be extracted. The petrol ether 

 extract is then distilled on a water bath (after the flame has been removed) to 25 c.c. 

 Then extract it three times with 20 c.c. of 5 7o sodium hydroxide solution in a 

 separating funnel, whereby the sodium salt of the eugenol is formed and passes into 

 the alkaline solution turning it yellow. The petrol ether now contains only the small 

 quantity of the hydrocarbon, caryophyllene. Traces of the latter are now removed 

 from the alkaline phenolate by extracting again with 20 c.c. of petrol ether. Then 

 add dilute sulphuric acid to the phenolate. The eugenol separates out as a milky 

 suspension, which gradually collects together as a yellow "oil." Then neutralise again 

 with sodium carbonate solution (which does not form a phenolate), and extract the 

 eugenol with petrol ether. Distil ofi' the ether, and the eugenol remains. 



