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f — 109 — 



hydrocarbons, and for the simultaneous detection of benzine and benzene 

 compounds in turpentine oil mixtures. In this connection it must be borne 

 in mind that the results are independent of the character of the benzine, 

 that is to say the method applies equally to Russian or Pennsylvanian 

 benzines, which are poor in natural benzene hydrocarbons, and to Indian 

 or Galician benzines, which contain large proportions of these bodies. 



H. Wolff 1 ) regards Herzfeld's method for the estimation of benzene in 

 turpentine oil 2 ) as unreliable. He thinks ^that it may only be of value for 

 qualitative detection and even in that case only when the test has a 

 positive result and when it agrees with the other constants. For the 

 exact estimation of benzine and benzene hydrocarbons Wolff prefers 

 Marcusson's method 3 ). 



For the purpose of detecting the presence of wood -turpentine in 

 American oil of turpentine, E. J. Parry 4 ) proposes the estimation of the 

 bromine-, or better still of the iodine-value. The iodine-value of wood- 

 turpentine is 230 to 300, the iodine -value of the % last 10 p. c. of the 

 distillation being lower still. For American turpentine oil the iodine-value 

 is 360 to 375 (Hiibl) or 335 to 350 (Wijs) and for the last 10 p. c. accor- 

 ding to both methods not less than 350. 



For testing American turpentine oil for petroleum hydrocarbons, Parry 

 recommends Eibner and Hue's 5 ) sulphuric acid method. 



The test for pine tar oil recommended by Piest 6 ) (black decoloration 

 upon treatment with acetic anhydride and hydrochloric acid) has been 

 submitted to a control-test by H. Wolff 7 ), who has found that it is effective 

 only with pine tar oils which in any case turn black or brown when 

 treated with concentrated hydrochloric acid. The difference in solubility 

 in acetic anhydride between pine tar and turpentine oils is fairly con- 

 siderable. This test cannot be used for quantitative estimation, but it 

 offers a means of estimating in a simple manner the minimum percentage 

 of an addition of pine tar oil. 



Wolff also reports on the waste-oils of sulphite cellulose manufacture 

 which have been freed as far as possible from methyl mercaptane and 

 methyl sulphide. Generally speaking these oils are less closely allied to 

 turpentine oil than to the pine tar oils, which they greatly resemble in 



!) Farbenztg. 17 (1912), 1553. Quoted from Chem. Zentralbl. 1912, I. 1931. 



2 ) Comp. Report April 1910, 111. 



3 ) Comp. Report April 1910, 109. 



4 ) Chemist and Druggist 81 (1912), 340. 



5 ) Comp. Report October 1910, 136. 



6 ) Comp. Report April 1912, 130. 



7 ) Farbenztg. 17 (1912), 1709. Quoted from Chem. Zentralbl. 1912, I, 762. 



