DIOXYNAPHTHOQUINONE. 401 



diimidonaphthol hydrochlorate (p. 398) with dilute 

 hydrochloric or sulphuric acid at 120. Bright yellow, 

 electric powder, or yellow needles ; sublimes partially 

 when carefully heated, condensing in reddish-yellow 

 needles. Almost insoluble in cold water, somewhat 

 soluble in boiling water, easily in alcohol and ether. 

 It combines with nascent hydrogen, forming trioxy- 

 naphthalene. It conducts itself as a moderately strong 

 monobasic acid towards bases, and liberates carbonic 

 acid from its salts. The alkaline salts are blood-red and 

 easily soluble in water. 



Chloroxynaphthoquinone (Chloroxynaphthalic 

 acid), C 10 H 5 C10 3 = G 10 H 4 C1(OH) j Q&amp;gt;. The potassium 



salt, C 10 H 4 C1(OK)0 2 , is obtained, when dichlornaphtho- 

 quinone is placed under alcohol, and concentrated po- 

 tassa-ley then added. It forms cherry-colored needles, 

 which are but slightly soluble in cold water, easily so 

 luble in hot water ; hydrochloric acid throws down the 

 free acid from this solution. Straw-colored, crystalline 

 powder ; fuses somewhat above 200, and sublimes in 

 needles ; but slightly soluble in cold water, moderately 

 in boiling, more easily in alcohol and ether. Strong 

 monobasic acid ; its salts, when heated, give a sublim 

 ate of phtalic anhydride. Heated with phosphorus 

 chloride, pentachlornaphthalene is formed. 



Dioxynaphthoquinone (Naphthazarin), C H 6 4 = 

 C 10 II 4 (OH) 2 | S&amp;gt;. Is obtained by simultaneously add 

 ing /3-dinitronaphthalene and zinc in small quantities 

 to concentrated sulphuric acid heated to 200. Subse 

 quently the mass is diluted with water, boiled, filtered 

 boiling hot and the gelatinous mass, that separates on 

 cooling, purified, when dried, by means of sublimation. 



Long needles with a beautiful green metallic lustre. 



But slightly soluble in boiling water, more easily in 

 alcohol, the solution having a red color. It dissolves 

 in ammonia forming a sky-blue solution, which turns 

 reddish-violet on standing. Its solution gives beauti- 



34* 



