— 77 — 



tube and the bodies thereby formed were separated. There were 

 obtained: I. gaseous portions, 2. liquids of different fractions, viz., of 

 the boiling points 20 to 30 , 30 to 40 , 70 to 8o°, 96 to 110 , 

 and 135 to 1 45 . A large proportion of the substance remained 

 unaltered, but a heavy high-boiling oil was also obtained. In the 

 volatile portions ethylene and propylene were detected, whilst the 

 fraction between 20 and 30 contained divinyl and various isomeric 

 butylenes. The fraction between 30 and 40 consisted almost entirely 

 of isoprene and trimethyl ethylene. The next fraction (70 to 8o°) 

 contained io°/ benzene, and various hydrocarbons with open chain, 

 chiefly dimethylisopropyl ethylene; in the fractions 95 to 145 , toluene 

 and different xylenes were present. 



In our last Report 1 ) we have already briefly described W.Vaubel's 2 ) 

 brominating method, and also called attention to the objections raised 

 by Holde and Herzfeld. Vaubel now has recently 3 ) published 

 modifications improving his process. But Herzfeld 4 ) also objects 

 to these, as in his opinion adulterations which could at once be de- 

 tected by means of the refractometer could not be determined by 

 Vaubel's method. For this reason Herzfeld recommends that in 

 the examination of turpentine oil the refractometric test should always 

 be made first. 



- R. Bohme 5 ) recommends the following method for the estimation 

 of petroleum, petroleum distillates, and benzene, in oils of turpen- 

 tine and pine tar, and in substitutes of turpentine oil: Required are 

 an "acid mixture" of 1 vol. fuming and 3 vol. concentrated sul- 

 phuric acid (1,84); further, concentrated sulphuric acid (1,84), and a 

 flask with a graduated neck. To 20 cc. of the acid mixture, 10 cc. 

 of the substance under examination are added, with shaking, and, if 

 necessary, cooling. After thorough mixing the flask is filled up with 

 concentrated sulphuric acid, and after 2 to 3 hours the figures are 

 read off the scale. An admixture of 3O°/ or more petroleum hydro- 

 carbons can then be detected, but if less has been added, more 

 time must elapse before the reading off. The portion floating on the 

 top, i. e. the one not absorbed by the acid, is estimated refracto- 

 metrically according to Utz. But as it has been found that about 

 0,9 cc. of every 10 cc. pure turpentine oil are separated off in the 

 treatment as a portion insoluble in the acid, 10 cc. of a turpentine 

 oil containing io°/ benzene or similar substance, should separate off 



x ) Report April 1906, 66. 



2 ) Zeitschr. f. off. Chemie 11 (1905), 429. 



a ) Pharm. Ztg. 51 (1906), 251. 



4 ) ibidem 265. 



6 ) Chem.-Ztg 30 (1906), 633. 



