S8 Notices of the Labours of Continental Chemists. 



Oil of Caraway {Oleum Carvi.) 



Vblckel has published some analyses of this oil {Annal.der 

 Pkarm., vol. xxxv. p. 308) ; he found that by distillation it may 

 be separated into several oils of diffei'ent boiling points and 

 different composition, of which the most volatile is probably 

 a hydrocarbon. Schweitzer has instituted a fuller examina- 

 tion of the oil, and confirms Volckel's statements; he finds that 

 it is partially decomposed by distillation. The hydrocarbon 

 which first passes over has the composition C^ H^; he calls it 

 carven. When oil of caraway is mixed with hydrate of po- 

 tassa it becomes brown-coloured, and yields on distillation 

 an oil which, by repeated cohobation, is entirely different from 

 the original oil of caraway. This oil is the true carven ; the 

 above-mentioned is probably carven mixed with some other 

 body. It boils at 173° C, smells something like oil of anise ; 

 it probably pre-exists in the oil of caraway. The residue from 

 the above operation consists of a resin and the brown alkaline 

 solution ; this gives, on saturation with sulphuric acid, a thick 

 brown oil which may be purified by distillation with water ; 

 this oil, which is of a very sharp biting character, he calls 

 carvacrol; its formula is C'*'' H^^ O^. Two resins are formed 

 at the same time, which are however of minor importance. 

 The best method of obtaining both carven and carvacrol is to 

 distil oil of caraway with hydrated phosphoric acid in a long- 

 necked flask ; the carven distils over, and the carvacrol flows 

 back. 



Carven is colourless, lighter than water, difficultly solu- 

 ble in water, easily in alcohol and asther, oxidizes in the air, 

 and forms a resin. It is also converted into resins by sul- 

 phuric and nitric acids. It forms with hydrochloric acid gas a 

 camphor-like substance, soluble in alcohol,crystallizes in white 

 scales, easily soluble in water; the solution is decomposed 

 by warming; melts at 50*5°. Heated with lime it forms chlo- 

 ride of calcium, water and carven. Formula C^^ H'^ Cl-^, or 

 Qw H>'' + H^ CR Carven combines with chlorine; the com- 

 pounds have not yet been fully examined. 



Carvacrol is colourless, similar in consistence to olive oil, 

 has a biting taste, boils at 232°, does not possess acid pro- 

 perties. 



Oil of caraway heated with potassium forms a brown mass, 

 out of which water separates carvacrol. [These researches 

 are to be continued.] — Journal filr Praktische Chemie^ vol. xxiv. 

 p. 257. 

 ♦ Cedar Oil. 



Walter has shown that the crystallized oil of peppermint 

 belongs to a class of bodies analogous to camphor ; he has 



