

DIOXYBENZENES. 303 



2. Toluquinone, C 7 H 6 2 , is not known. Substitution- 

 products of it trichlortoluquinone and tetrachlortoluqui- 

 none are produced by the action of hydrochloric acid 

 and potassium chlorate on creosol (p. 309) and the 

 cresol (p. 299) contained in coal-tar. 



3. Phlorone, C 8 H 8 2 . Is obtained from the phenols 

 C 8 H 10 0, contained in coal-tar and beech-wood tar, by 

 distilling them with manganese peroxide and sulphu- 

 ric acid. Yellow, needly crystals. Easily sublimable. 

 Slightly soluble in cold water, more readily in hot 

 water, easily soluble in alcohol and ether. Its vapor 

 attacks the eyes and mucous membranes violently. 



4. Thymoquinone, C 10 H 12 2 . Is obtained by distilling 

 a solution of thymol, diluted with water, with manga- 

 nese peroxide. Yellow, prismatic plates ; fusing point, 

 45.5 ; boiling point, 200 ; volatile with water vapor. 

 Has a peculiar penetrating odor. Yields, with bro- 

 mine, mono- and dibromthymoquinone. The former crys- 

 tallizes in long, yellow needles, which, when heated 

 with potassa-ley, are converted into oxythymoquinone, 

 C 10 H n (OH)0 2 ; the latter forms bright-yellow lamime 

 that fuse at 73.5. 



c. Diatomic Phenols. 



1. Dioxybenzenes. 

 C 6 H 6 2 = C 6 H 4 (OH) 2 . 



a. Hydroquinone (Ortho-dioxy benzene). Is pro- 

 duced from quinic acid by destructive distillation; or 

 by the addition of lead superoxide to its aqueous solu- 

 tion ; by treating arbutine (see Grlucosides) with dilute 

 sulphuric acid; by heating orthoiodophenol (p. 293) 

 with caustic potassa at 180; and is prepared most 

 readily by treating quinone with sulphurous or hydrio- 

 dic acid. 



Colorless prisms. Easily soluble in water, alcohol, and 

 ether ; fusing point, 177.5. When carefully heated it 

 is sublimable. Combines with sulphuretted hydrogen 



