NAPHTHOL. 397 



B. PHENOLS. 



1. Naphthol (a-Naphthol). 

 C 10 H 8 = C 10 H 7 .OH. 



Is formed by heating potassium a-sulphonaphthalate 

 with potassium hydroxide. Colorless, monoclinate 

 prisms; fusing point, 94; boiling point, 270-280; 

 almost insoluble in cold water, somewhat soluble in 

 hot water, easily in alcohol and ether. Towards alka- 

 lies it conducts itself like phenol (p. 290). 



Naphthol-ethylether, C 10 H 7 .O.C 2 H 5 . By heating 

 naphthol-potassium with ethyl iodide. Colorless 

 liquid ; boiling point, 272 ; does not congeal at 5. 



Naphthol-acetate, C 10 H 7 .O.C 2 H 3 0. By the action 

 of acetyl chloride on naphthol. Yellowish liquid, in- 

 soluble in water. 



Nitronaphthol, C 10 H 6 (N0 2 ).OH. Is formed, when 

 1 part nitronaphthalene is heated in a current of air 

 for a long time at 140, intimately mixed with 1 part 

 potassium hydroxide and 2 parts calcium hydroxide, 

 and the aqueous extract from the mass decomposed 

 with hydrochloric acid. Bright-yellow, light mass ; 

 crystallizing from acetic acid or acetone in golden-yel- 

 low prisms ; fusing point, 151-152. 



Dinitronaphthol, C 10 H 5 (^0 2 ) 2 .OH. Cannot be pre- 

 pared directly from naphthol. Is, however, readily 

 obtained by pouring nitric acid (specific gravity, 1.35) 

 upon naphthylamine ; and by gently heating a solution 

 of sulphonaphthalic acid, to which is added nitric acid. 

 Is also formed by boiling diazonaphthalene hydrochlor- 

 ate (from naphthylamine hydrochlorate with nitrous 

 acid) with nitric acid. Lustrous sulphur-colored crys- 

 tals ; fusing point, 138 ; almost insoluble in boiling 

 water, difficultly soluble in alcohol and ether, more easily 

 in chloroform. With bases it yields salts ; and liberates 

 34 



