60 PROCEEDINGS OF THE AMERICAN ACADEMY. 



aud the oil which separated was allowed to stand uutil a crystalline 

 product formed. After crystallization from alcohol, the nitro deriva- 

 tive thus obtained melted at 139°-140°, the melting point of triuitro- 

 paraxylol. Another portion of the same fraction was boiled during 

 several hours with chromic acid, aud the solution extracted with 

 ether. Upon evaporation, a white powder remained that sublimed 

 without melting, and resembled in its appearance terephthalic acid. 

 To determine the quantity of paraxylol according to the method sug- 

 gested by Levinstein, a measured portion of the fraction lo7°-138° 

 was shaken during thirty minutes with concentrated sulphuric acid. 

 The loss in volume corresponded to 10.77 per cent, representing the 

 other aromatic hydrocarbons. The residual oil was then agitated 

 with fuming sulphuric acid to dissolve the paraxylol, with a diminu- 

 tion in volume representing 9.02 per cent of the xylol. 



The quantity of metaxylol in fraction 139°-140° was found by 

 treating it fii-st with dilute nitric acid, which, according to Briickner,* 

 should not affect metaxylol, and distilling with steam, which carries 

 over the metaxylol. The loss in volume, 7.5 per cent, was noted, 

 and the distillate was agitated first with ammonia, then with concen- 

 trated sulphuric acid ; the last diminution represented 8.8 per cent of 

 metaxylol. 



Many attempts were made to prove the presence of orthoxylol by 

 the formation of the nitro compounds, and toluic acid. But no di- or 

 tri-nitro compounds could be separated after treatment with nitiic 

 acid except those whose melting points corresponded to metaxylol. 

 By the action of dilute nitric acid, which should not affect metaxylol, 

 an acid was formed, but not in sufficient quantity to show that it was 

 toluic acid. In forming the sulphonic acids and the sodium salts, so 

 far as could be observed, no sodium orthoxylolsulphonate was present. 

 It is quite possible that orthoxylol could be detected in a larger quan- 

 tity of product. The larger amounts of the fractions 140°-142° 

 therefore consisted partially of metaxylol. Referring the quantities 

 of meta- and para-xylol to the weights of crude oil, the amount of 

 paraxylol is 0.006 per cent, of metaxylol 0.003 per cent, in their 

 respective fractions. These numbers cannot be assumed to represent 

 more than an approximate estimation of these xylols, although they 

 are doubtless, for the most part, collected in the fractions 137°-143°. 

 In fractions 141°-143° the amount of sodic xylolsulphonate formed 

 corresponded to 0.009 per cent of xylol, and, since orthoxylol could 



* Ber. der deutsch. chem. Gesellsch., 1876, p. 405. " 



