OF ARTS AND SCIENCES. 877 



verted into trichlorbenzol by the method of Bassmann;* that is, it is 

 dissolved in alcohol of 95 per cent by heat, and the calculated amount 

 of a hot concentrated aqueous solution of potassic nitrite added, and 

 then dilute sulphuric acid, little by little, until the reaction is strongly 

 acid ; the mixture is then warmed gently on the water-bath until the 

 reaction comes to an end, and the trichlorbenzol purified by crystalli- 

 zation from alcohol. The yield is good, 8 grm. of the trichloraniline 

 giving 5 grm. of trichlorbenzol ; that is, 67 per cent of the theoretical 

 amount. 



Trichlordlnitrobemol, CgHC]3(N02)2- 



The symmetrical trichlorbenzol was dissolved in nitric acidf of 

 specific gravity 1.505 at the ordinary temperatuie ; the same result 

 was also obtained if the beaker in which the reaction took place was 

 kept cool by immei'sion in cold water. When the trichlorbenzol was 

 completely dissolved, the product was precipitated by pouring it into 

 cold water or snow, and purified by crystallization from hot alcohol 

 until it showed the constant melting point 129°. 5, when it was dried 

 at 100° and analyzed. 



0.2G94 grm. of the substance gave 24.4 c.c. of nitrogen at 24° 



temperature and 766.5 mm. pressure. 

 0.2102 grm. of substance gave, according to the method of Carius, 



0.3322 grm. of argentic chloride. 



Properties. — It forms thick, long white prisms, when crystallized 

 from alcohol, which melt at 129°. 5, and are soluble in cold alcohol, 

 much more freely in hot, very easily soluble in benzol, chloroform, 

 carbonic disulphide, or acetone, soluble in ether, or in glacial acetic 

 acid, still more soluble in hot glacial acetic acid. 



In order to obtain trichlormononitrobenzol, a nitric acid diluted 

 until it shows the specific gravity 1.46 must be boiled with trichlor- 

 benzol until complete solution takes place. After precipitation with 



* Ann. Cliem., cxci. 206. 



t The nitric acid was preparerl by distilling nitre with sulphuric acid in the 

 proportions of one molecule of each. See page 374, for a discussion of this 

 point. 



