BENZENE. 257 



pounds. Is scarcely acted upon by alkalies ; with acids, 

 however, it decomposes easily, yielding formic acid and 

 anilin. 



Nitrosubstitution-products, Nitrobenzene, C 6 H 5 

 (NO 2 ), is formed, when benzene is added gradu- 

 ally to very concentrated nitric acid, which is kept 

 cool. Bright yellow liquid, with an odor similar to 

 that of oil of bitter almonds. Boils at 205, and con- 

 geals at 3. Paradinitrobenzene, C 6 H 4 (]$r0 2 ) 2 , is pro- 

 duced by heating the preceding compound for a long 

 time with very concentrated nitric acid ; more readily 

 by dropping benzene into a mixture of two volumes 

 concentrated sulphuric acid, and one volume very con- 

 centrated nitric acid. Crystallizes from alcohol in very 

 long, shiny, nearly colorless needles, that fuse at 86. 



By the action of nitric acid or nitric-sulphuric acid 

 on chlorine, bromine, and iodine substitution-products 

 of benzene, mono- and dinitro-derivatives of these com- 

 pounds are formed. Usually several isomeric modifi- 

 cations are produced at the same time, the constitution 

 of which is as yet unknown. Nearly all of these 

 compounds are solid and crystallize well. All these 

 modifications of nitrochlorbenzene C 6 H 4 (]N"0 2 )C1 are 

 known ; two of them are solid and have the fusing 

 points 85 and 46; the third is fluid, and boils at 240; 

 also of nitrobrombenzene C 6 H 4 (N0 2 )Br, all three modifi- 

 cations are known ; they all crystallize in yellowish 

 prisms, and have the fusing; points, 125, 50, and 

 31.Nitroiodobenzene C 6 H 4 (1TO 2 )L Of this, two modi- 

 fications are known (fusing points, 171. 5 and 34) ; 

 also of nitrobenzonitrile C 6 II 4 (N0 2 )CN, (metanitroben- 

 zonitrile, from benzonitrile with nitric acid and from 

 metanitrobenzamide with phosphorus pentachloride. 

 Fusing point, 117-118. Paranitrobenzonitrile from 

 paranitrobenzamide with phosphoric anhydride : lami- 

 nae ; fusing point, 139). 



Dinitrochlorbenzene, C 6 H 3 (N0 2 ) 2 C1, from chlor- 

 benzene with nitric-sulphuric acid ; and from dinitro- 



22* 



