152 



R. B. Drew and E. I. Rosenblum 



The System d-pinene — l-pinene. 



1-pinene. 

 l-pinene 

 Concentra- 

 tion 100 



Found 

 Calc. 



Found 

 Calc. 



Found 

 Calc. 



86.82 75.04 50.87 28. 



Eotation- 



E. d-pinene. 



15.92 



-39.640 -31.390 -23.60o - 7.80o +6.45° +15.02° +25.40° 



-31.370 -23.660 -7.83o +6.51° +15.05° 



Refractive Index — 



1.4639 1.4641 1.4640 1.4640 1.4641 1.4640 1.4640 



1.4640 1.4640 1.4640 1.4640 1.4640 ... 



Density — 



.8646 .8639 .8633 .8626 .8614 .8610 .8604 



.8640 .8636 .8625 .8616 .8611 ... 



The Si/stems l-Pii^eiie-Cineol and d-Pinene-Gineol. 



Of greater complexity is the case involving a partial replacement 

 of one of the terpenes by an oxygenated substance of allied struc- 

 ture. Cineol is such a substance, and with it the deviations from 

 the simple proportionately become noticeable. 



These deviations, as in the case of the specific rotatory power, 

 may be due to a disturbance of the equilibrium, between active 

 and racemic terpene, brought about by the cineol, a possibility 

 supported by the fact that the refr activity is not affected. 



It is in the density, however, that the divergences from the 

 simple proportionality become most marked, and here it can be 

 shown that the influence is molecular rather than structural, by the 

 fact, that when the theoretical densities .are calculated from the 

 molar fractions they again agree with the observed. In the simpler 

 case of d- and l-pinene the molar and weight fractions, of course, 

 coincide, since the two molecular weights are the same. 



The cineol was obtained from Bosisto's 01. Eucalyptus B.P. by con- 

 version into the phosphoric acid compound and regeneration with 

 soda, after squeezing out the terpenes under pressure. The pro- 

 duct was then distilled with steam, and its constants were — 



a =±0.00^ 

 /A25= 1.4579 



K. 



.9220 



