20 OLEORESINS OF SOME WESTERN PINES. 



Schimmel & Co.( 7 ) reports that the principal fraction of the oil exam- 

 ined by them boiled between 98.5 and 99 and had a specific gravity 

 of 0.6880 at 15. Thorpe ( 10 ) obtained the following results on a 

 carefully purified oil: boiling point, 98.42 at 760 mm.; specific 

 gravity, 0.70057 at 0; refractive index for D= 1.3879. 



During the distillation of the oleoresin with steam, the last portion 

 of oil coming over had a yellow color and a sharp, penetrating odor. 

 On fractionation of the volatile oil, the fractions had only a faint 

 orange odor, while the residue was colored yellow and had a decidedly 

 higher specific gravity (0.7393), and index of refraction (1.4140), 

 and a strong orange odor. The characteristic odor of the crude oil 

 is apparently due to this yellow oil, which on fractionation becomes 

 concentrated in the residue. Thorpe (10) attributes the odor to a 

 "resenoid matter," while Rabak (3) considers it an ester. 



Previous investigators have, in general, found a decidedly higher 

 boiling point for the crude oil. Wenzell (14) gives the boiling point 

 at 101 to 115, the fractions boiling steadily at 101. Rabak (3) 

 found it to boil at 100 to 101 and Sadtler (4) at 101 to 103. 



EXAMINATION OF THE ROSIN. 



The rosin, grade M, had a specific gravity of 1.073; acid number, 

 156.7; saponification number, 176.5; and ether number, 19.8; a 5.58 

 per cent alcoholic solution gave the optical rotation, a D20 o= + 0.38. 

 Rabak (3) states that both the oleoresin and colophony are optically 

 inactive. This statement has not been found to be true of either 

 substance. 



All attempts to obtain a crystalline body from the original rosin 

 failed. It seems to be in an amorphous state, noncrystallizable under 

 normal conditions. It was then subjected to distillation in vacuo. 

 Laurent 1 as long ago as 1839 found that the resin acids could be 

 distilled under reduced pressure and the distillate recrystallized. 

 This method has been frequently employed since that time. Rosin 

 is but slightly decomposed under such treatment, and the resin acids 

 recovered are isomers of the formula C 20 H 30 O 2 . 



The rosin distilled between 240 and 255 C. at 10 mm. pressure. The 

 viscous distillate solidified on cooling to a hard, transparent, slightly 

 yellow mass, resembling colophony. A portion of the distillate was 

 dissolved in acetone and the solution allowed to stand in a cool place 

 for several days. Large crystals were thus obtained absolutely with- 

 out color. These were stirred rapidly with small amounts of cold 

 acetone to remove adhering mother liquor, and the solvent was de- 

 canted. The crystals were then dissolved in acetone and yielded 

 a colorless solution. Recrystallized twice from the same solvent, 



i Ann. de Chim et de Phys., p. 383, vol. 72 (2), 1839. 



