MABERY. — SULPHUR PETROLEUMS. 41 



soluble in potassic liydrate like the nitro derivatives of the series 

 C„H2„^2» ^^*-^ ^y boiling with sodium the solid residue vpas large. 



In distillates* 85°-l 05° from Bibi-Eibat and from Balakhani, after 

 thirty fractional separations, Milkowsky * collected a body that distilled 

 constant at 100°-101°, and by the formation of its halogen derivatives 

 proved it to be heptanaphtene. The oil boiling at 101°-103°, which 

 Beilatein and Kurbatoff separated from Baku oil, was doubtless the 

 same product, but Beilsteiu and Kurbatoff considered it to be com- 

 posed for the most part of hexahydrotoluol, boiling point 97°. 



Hexahydroisoxylolwas found by Beilsteiu and Kurbatoff in Cauca- 

 sus petroleum,! and in American ligroine ; t since the American 

 source was not mentioned, it is to be inferred that the ligroiue was 

 prepared from Pennsylvania oil. In testing the fractions 118°-119°, 

 fourteenth distillation in a Hempel column, for hexaisoxylol, a por- 

 tion of the oil was heated forty hours with a mixture of nitric and 

 sulphuric acids. The nitro product separated from the oil when cold 

 in long, flat plates, nearly insoluble in cold, more readily in hot alco- 

 hol. When purified by crystallization, this substance melted at 177°, 

 and was, therefore, trinitroisoxylol. A similar crystalline nitro pro- 

 duct with the same melting point was found in the fraction 123°— 

 124°. Since the prolonged distillation precluded the possibility that 

 this fraction contained metaxylol, there can be no doubt that the 

 trinitroxylol obtained from fraction 118°-119° indicated the presence 

 of hexahydroisoxylol, although it evidently formed only a small pro- 

 portion of this product. After a portion of the same distillate was 

 agitated thoroughly with a mixture of nitric and sulphuric acids, and 

 distilled over sodium, analysis gave the percentages of carbon and 

 hydrogen required for octane, as has been shown (page 30) : — 



As already explained, Analysis III. was made after prolonged treat- 

 ment with the mixture of acids by which the hexahydro compound is 

 removed very slowly, and the final results show that the fraction is 

 composed chiefly of the more highly hydrogenized hydrocarbon, 

 although it contains a considerable quantity of the other constituent, 

 as shown by the abundant formation of nitro product. 



* Ber. der deutsch. chem. Gesellsch., 1885, c. 187. 



t Ibid., 1880, p. 1818. t Ibid., p. 2088. 



