254 BENZENE. 



Properties. Colorless liquid of a peculiar odor, spe- 

 cific gravity at 0, 0.899. Boils at 81-82, and con- 

 geals at 0. Burns with a luminous flame. Excellent 

 solvent for resins, fats, etc. 



When chlorine acts on benzene, products of substi- 

 tution and of addition are formed simultaneously. 



Benzene hexachloride, C 6 H 6 C1 6 , and Benzene 



hexabromide. C 6 H 6 Br 6 , are formed by the action of 

 an excess of chlorine or bromine on benzene in direct 

 sunlight. The former compound is also produced by 

 passing chlorine into boiling benzene. Both com- 

 pounds are solid and crystallizable (the chloride fuses 

 at 157), and are decomposed partially when heated 

 alone, completely when heated with bases, into hydro- 

 chloric acid or hydrobromic acid and trichlor- or 

 tribrombenzene. 



Benzene hypochlorite, C 6 H 6 (C10H) 3 , is produced 

 by bringing benzene and an aqueous solution of hypo- 

 chloric acid together. Colorless lamina, which fuse at 

 10. But slightly soluble in water, easily in alcohol, 

 ether, and benzene. Decomposes when kept in contact 

 with the air, and, when heated with a very dilute 

 solution of sodium carbonate, yields phenose C 6 H 6 (OH) 6 , 

 an amorphous, deliquescent mass. Heated with hy- 

 driodicacid to 120, benzene hypochlorite and phenose 

 both yield 0-hexyl iodide C 6 H 13 I (p. 72). 



Chlorine substitution- pro ducts are obtained by 

 conducting chlorine into benzene containing iodine. 

 In this way are produced : monochlorbenzene, C 6 H 5 C1, 

 also formed by the action of phosphorus pentachloride 

 on phenol. Liquid fusing at 135 ; congeals only 

 below 40. Paradichlorbenzene, C 6 H 4 C1 2 . Colorless 

 crystals ; fusing point, 53 ; boiling point, 172. 

 Trichlorbenzene, C 6 H 3 C1 3 . Fusing point, 17 ; boiling 

 point, 206-210. Tetrachlorbenzene, C 6 II 2 C1 4 . Fine 

 needles ; fusing point, 139 ; boiling point, 240. Pen- 

 tachlorbenzene, C 6 HCP. Fine needles; fusing point, 

 85 ; boiling point, 270. Perchlorbenzene (Julin's 



