18 



WOOD TURPENTINES. 



elusions regarding 1 the presence of dipentene, which were originally 

 drawn from the physical properties. It seems very likely, therefore, 

 that when a turpentine obtained from the long-leaf pine is distilled 

 by the method described above, a decrease in specific gravity as the 

 boiling temperature approaches 175 C. is a good indication of the 

 presence of dipentene. 



COMPLETENESS OF SEPARATION OF CONSTITTTENTS. 



The exact percentage of dipentene can not be determined from 

 the curves in figure 54, since the separation between the pinene and 



the dipentene is not suffi- 

 ciently sharp. There are 

 small quantities of dipen- 

 tene in the portion distil- 

 ling between 70 per cent 

 and 80 per cent as shown 

 by the slight decrease in 

 specific gravity, but it is 

 only in the portion com- 

 ing over after 80 per cent 

 has been distilled that 

 there are comparatively 

 large quantities of dipen- 

 tene present (as shown 

 by the decided changes 

 in direction in the boil- 

 ing point and index of 

 refraction curves). The 

 separation between the 

 dipentene and the 

 " heavy oils " is, however, 

 quite complete, and the 

 percentage of the latter 

 can be determined with 

 considerable accuracy. 

 This turpentine contains, then, 95 per cent of terpenes (containing 

 approximately 80 per cent pinene and 15 per cent dipentene) and 5 

 per cent of heavy, high boiling oils, probably nonterpenes. 



COMPARISON OF FRACTIONATIONS BY DIFFERENT METHODS. 



In order to show the advantages gained by the use of a dephleg- 

 mator, and by the use of direct distillation instead of steam distilla- 

 tion, the following distillations were carried out on the same tur- 

 pentine: (1) Steam distillation without a dephlegmator; (2) direct 

 distillation without a dephlegmator; (3) steam distillation with a 



40 



i 



96 97 98 99 BOILING POINT 



.86 TT ER 33 3O 31 9Z SPECIFIC GRAVITY 

 INDEX OF EFEACTION U70 U72 U74 U76 U78 1480 U82 U84 



FIG 4. Comparison of fraction ation obtained in 

 steam distillation with a Geer dephlegmator and 

 without a dephlegmator. 



