MABERY. — SULPHUR PETROLEUMS. 37 



from coal tar, the source of the metaxylol from which the trinitro com- 

 pound was i^repared. But in the preparation of this trinitro deriva- 

 tive from octonaphtene, Markovvuikoff and Spadi * gave 179°-180° 

 as its melting point. 



An approximate quantitative determination of metaxylol was made 

 in the fraction 139°-140° by heating a portion during one hour with 

 dikite nitric acid, which should oxidize the para- and ortho-xylols to 

 the corresponding toluic acids, and the remaining oil was washed with 

 water, dried, and distilled with steam. The decrease in volume was 

 noted, and it corresponded to 6.3 per cent of the quantity taken. Tlie 

 distillate was next shaken with concentrated sulphuric acid, which dis- 

 solves metaxylol, and the decrease in volume corresponded to 16.6 

 per cent of metaxylol. In determining the quantity of paraxylol, a 

 weighed amount of the fraction 137°-138° was shaken thirty minutes 

 with concentrated sulphuric acid to dissolve the ortho- and meta-xylols, 

 with a loss in volume equivalent to 4 per cent of the quantity taken. 

 The residual oil was then agitated with fuming sulphuric acid, and the 

 diminished volume represented 12.2 per cent of paraxylol. 



In attempting to ascertain the presence of orthoxylol, dependence 

 was placed upon the observation of Jacobsen, that a single drop of 

 orthoxylol may be distinguished in a mixture of the three isomers by 

 treating them in the cold with a mixture of nitric and sulphuric acids. 

 The fraction 142°-143° gave immediately an oily layer inconsiderable 

 quantity between the acid and the lighter oil, which should be the 

 liquid orthonitroxylol. The fraction lo9°-140° gave no trace of an 

 oily layer even after long standing. By further treatment with the 

 acid mixture with the aid of heat, the oily mononitro product from 

 distillate 142°-143° was converted into a crystalline dinitro com- 

 pound melting at 91°, the melting point of dinitrometaxylol. By long 

 continued action of the acid mixture, hot, a trinitroxylol was formed, 

 nearly insoluble in alcohol, and melting at 178°, which might be 

 a derivative either of ortho- or meta-xylol. Another portion of the 

 distillate 142°-143° was heate 1 with dilute nitric acid, which should 

 form orthotoluic acid without affecting metaxylol. Upon extracting 

 the acid solution with ether, an oily residue remained after evaporation 

 of the ether with the characteristic odor of toluic acid, but no crystals 

 separated even after long standing. An attempt was made to separate 

 the less soluble sodic orthoxylol sulphonate, but upon evaporation of 



* Ber. der deutsch. chem. Gesellsch., 1887, p. 1850. 



