— 46 — 



it was impossible to obtain this body in an approximately pure form, or 

 to identify it from derivatives. Judging from the values disclosed by 

 combustion it appears to be a terpene CioH 16 . In all our experiments 

 we were compelled to work on mixtures which, whether brominated, redu- 

 ced, or treated with nitrosylchloride, hydrochloric acid gas, or by other 

 methods, yielded derivatives of the dipentene, together with some oily 

 substance. We found, for example, the following constants: b. p. 40 

 to 41° (4 mm); d 15 o 0,8360, 0,8337, 0,8330, 0,8323; « D — 32°41' to 23°24'; 

 "d2oo 1,48044. When distilled at atmospheric pressure the body becomes 

 partly resinified. A particularly light fraction (di 50 0,8315; « D — 29°54'; 

 n D15 o 1,48287; mol. refr. 46,41, calc. for Ci Hi 6 /7 45,24) was insoluble in 

 formic acid and when it was attempted to prepare nitrosates and nitrosites 

 did not separate out any solid substances, but only small quantities of 

 dipentene dihydrochloride. 



Repeated attempts at reduction with sodium and alcohol, however, 

 yielded hydrated hydrocarbons (di 5 o 0,8115; 0,8182; 0,8077), but the fact 

 that in the course of this reaction comparatively numerous resinous pro- 

 ducts were formed makes it probable that the latter are reduction-products 

 of dipentene. It was therefore attempted to hydrate the terpene by means 

 of colloidal palladium. The hydrosol-solution was prepared by Paal's 

 method, protalbinate of sodium being used as a protective colloid. The 

 process of reduction was carried out as follows: about 60 g. of the dialysed, 

 neutral hydrosol solution (containing about 0,45 g. palladium) was allowed 

 to remain in contact for about 8 hours with 20 g. hydrocarbon (di 5 o 0,8315; 

 a D — 29°44 r ) and 120 g. alcohol, during which time hydrogen was passed 

 in and the mixture was strongly turbinated. The liquid very soon turned 

 turbid and palladium was separated off. According to its constants the hy- 

 drocarbon had undergone no perceptible change and it was therefore sub- 

 jected to a fresh reduction under similar conditions, but with a more 

 dilute hydrosol solution, containing a little more protective colloid. The 

 reduction-product was driven off by steam, and distilled as follows: — 



di 5 o « D 



1. 41° (5 mm.) 0,7989 — 13°28' 



2. 41 to 43° (5 mm.) . . . 0,8084 — 17° 53' 



Fr. I had a pronounced odour of lemon. No solid bromide was 

 obtained, either in carbon tetrachloride or in an amyl alcohol-ether mix- 

 ture. Neither fraction afforded a nitrosochloride. Oxidation with perv 

 manganate yielded no products which could readily be identified. The 

 combustion showed that the body was a hydrated terpene: — 

 0,1534 g. subst: 0,4874 g. C0 2 , 0,1778 g. H 2 0. 



Found Calc. for Ci Hi 8 



C 86,65 °/o 86,96 °/o 



H 12,87°/o 13,04% 



