36 PROCEEDINGS OF THE AMERICAN ACADEMY. 



cold, then with the aid of a gentle heat. Upon distillation of the 

 hydrocarbon not affected, there remained a brown oil that deposited a 

 crystalline product on standing. After crystallization from alcohol, 

 this substance appeared in the form of glistening white needles which 

 melted at 139°-140°. It was therefore trinitroparaxylol, melting 

 point lo9°-140°.* By treating carefully another portion of the same 

 fraction in the cold with fuming nitric acid, long yellow needles spar- 

 ingly soluble in alcohol were obtained, melting at 145°, corresponding 

 to dinitroparaxylol, melting point 147°-148°. | For further con- 

 firmation, another portion of the fraction 137°-138° was submitted to 

 oxidation with chromic acid, and the solution extracted with a con- 

 siderable quantity of ether. Evaporation of the ether left a solid 

 residue in the form of minute prisms insoluble in water, but readily 

 soluble in sodic hydrate. This substance sublimed witliout melting, 

 and in general its properties corresponded to those of terephthalic 

 acid. After heating for thirty hours a quantity of the same fraction 

 with dilute nitric acid and distilling off the hydrocarbon not affected, 

 there remained an oily product which contained no toluic acid. In 

 repeating this experiment with longer heating, on cooling an oily layer 

 separated above the acid, which was neutralized with sodic hydrate, 

 evaporated to dryness, the salt decomposed with hydrochloric acid, 

 and the solution extracted with ether. Upon evaporation a crystalline 

 solid was left, but not in sufficient quantity for further examination ; it 

 was probably para toluic acid. 



In the fraction 139°-140° metaxylol was recognized by the forma- 

 tion of the trinitro-compound. A portion of the oil was heated with a 

 mixture of nitric and sulphuric acids during forty-eight hours, the oil 

 together with the crystals which formed was separated from the acid 

 solution, the oil distilled, and the solid remaining with the first crys- 

 tals was purified by crystallization from hot alcohol ; on cooling, long 

 slender colorless needles separated, melting at 175°-176°. This 

 nitro compound was therefore trinitrometaxylol, melting point 176°. 

 Several different melting points have been assigned to triuitroxylol. 

 Luhman t gave 177°, and Tilden § 182°. To explain the latter result 

 Tilden asserted that the lower value of Luhman was due to contam- 

 ination of the trinitroxylol by the isomeric nitro compounds derived 



* Nolting and Geissman, Ber. der deutsch. chem. Gesellsch., XIX. 145. 

 t Lellmann, Ann. Chem. Pharm., CCXXVIII. 250. 

 } Ann. Chera. Pharm., CXLIV. 274. 

 § Journ. Chem. Soc, XLV. 416. 



