— 129 



ocimene, "although the physical data of linaloolene agree almost completely 

 with those of dihydromyrcene". 



CH 2 



CH 3 



CH- 



CH 8 - 



>C • CH 2 ■ CH 2 • CH, : C ■ CH : CH 2 

 CH 3 



C • CH 2 • CH, • CH, • C • CH : CH-> 

 CH 2 



CH 2 



CH 3 < 



>G • CH 2 • CH 2 • CH 2 • CH • CH : CH, 



CH, 



By reacting with sodium upon linalool we obtained as a by-product 

 a small yield of a hydrocarbon with the following constants: b. p. 169 to 

 170°, dioo 0,7900, a D — 0°43', n D15Q 1,45341, n D20O 1,45191. After fractionation 

 over sodium the principal portion (95%) boiled at 58° (12 mm.), giving 

 d 15 o 0,7824; n D15 o 1,45251; mol. refr. found 47,60, calc. as Ci Hi 8 / 2 47,32. 



This linaloolene prepared by us absorbed 4 atoms of bromine, with 

 formation of a readily-crystallising tetrabromide, m. p. 88 to 88,5°, which 

 proved to be identical with dihydromyrcene tetrabromide, a body first 

 prepared by Enklaar 1 ). It follows from the above that linaloolene and 

 dihydromyrcene are identical. 



The constants of the products obtained by each of the various in- 

 vestigators are given below for purposes of comparison: 





Linaloolene 



Dihydromyrcene 



Dihydromyrcene 



Dihydro ocimene 



Dihydromyrcene 





(Semmler) 



(Enklaar) 



(Schimmel 8f C9) 



B. p. 



165 to 168° 



171,5 to 173,5° 



166 to 168° 



166 to 168° 



168° 



Sp. gr. 



0,7882 (20°) 



0,7802 (? °) 



0,7852 (15°) 



0,7750 (15°) 



0,7824 (15°) 



Refr. 



1,455 (20°) 



1,4501 



1,4514 (17°) 



1,4507 (17°) 



1,45251 (15 o) 



Mol. Refr. 

 found 



- 



- 



- 



47,62 



47,60 



Mol. Refr. 

 calc. as 

 CioHi 8 / 2 " 



- 





- 



47,34 



47,32 



The preparation of dihydromycene tetrabromide is often attended by 

 difficulties. The method recommended by Enklaar, and recently also 

 adopted by Semmler 2 ), of dissolving the hydrocarbon in glacial acetic 

 acid, has not stood the test of practice, because it generally gives rise 

 to oily bromides. Hydrobromic acid appears to be evolved as soon as 

 the bromine is added to the glacial acetic acid solution. The reaction is 

 accomplished more quickly and effectively by dissolving the hydrocarbon 

 in a mixture of one part by volume of amyl alcohol and two parts by 



*) Over Ocimeen en Myrceen, eene bijdrage tot de kennis van de aliphatische terpenen. 

 Inaug. Dissert. Utrecht 1905. p. 34. Report April 1906, 109. 

 2 ) Berl. Berichte 44 (1911), 2011. 



9 



