﻿24 CLOVER. 



Limonene hydrochloride. — This substance obtained by Wallach and 



Kxemers 21 by the action of dry hydrochloric acid upon limonene, was 

 prepared in order to study the action of aniline upon it. The substance 

 was found to boil from 89° to 91° at 12 millimeters, and accordingly 

 several degrees lower than the boiling point given by the above authors. 



Thirty-four grams of the fractioned substance were added to an equal weight 

 of aniline and the mixture heated on a water-bath. The temperature of the 

 mixture gradually rose to 113° and in time aniline hydrochloride appeared. 

 Previous experience had shown that above 120° the heat of the reaction was 

 so great that, without careful cooling, the reaction mixture became very hot. 

 The heating was continued for six hours upon the water-bath. The reaction- 

 product was freed from aniline by repeatedly shaking with cold, dilute hydro- 

 chloric acid. The oil was then driven over with steam and redistilled twice. 

 On the second distillation it boiled almost completely from 177° to 178°. 5 and 



SO 



showed a „ = -|-55 . Xo crystalline nitrite could be obtained. A good yield 



of crystalline tetrabromide was produced in acetic acid, and this tetrabromide 

 after being recrystallized twice from acetic ester, gave the melting point of 

 dipentene tetrabromide. On heating the oil in a well-stoppered flask immersed 

 in an oil-bath kept at 200° for four hours, there was practically no change in 

 the rotation. 



It appears that by the addition of hydrochloric acid to limonene and its 

 subsequent splitting off, the limonene is partly converted into dipentene, 

 but that no other substances are formed. 



PHELLAXDREXE. 



A number of essential oils when treated with nitrous acid are known 

 .to separate at once a white, crystalline derivative, C 10 H 16 ]Sr 2 O3 , to which 

 the term phellandrene nitrite has been indiscriminately applied, although 

 the melting point of the substance as recorded by various authors has 

 varied within a large range. Sehreiner 22 recently separated the product 

 obtained from eucalyptus oil into two distinct substances by fractional 

 crystallization from acetic ester. Since that time Wallach 23 has gone 

 into this question most thoroughly. He has shown that the products 

 obtained from bitter-fennel oil and elemi oil as well as from eucalyptus 

 oil (the last named being dextro-rotatory, while the other two are 

 ltevo-rotatory) are homogeneous chemically, and that the two substances 

 obtained from each of these oils are isomers only in a physical sense. 

 The mother substance to which all of these products are to be referred 

 he terms a-phellandrene. The less soluble nitrite he terms the a-nitrite. 

 He has also shown that the nitrite obtained from water-fennel oil is 

 chemically different from the others mentioned and to its mother terpene 



21 Am;. Chem. {LieUg) • (1892) , 270, 180. 



"Chem. Cenirbl. (1901), 72, II, 544. 



23 Ann. Chem. (Liebig) (1902), 324, 269; (1904), 336, 9; (1905), 340, 1. 



