PHENOL. 293 



pounds are crystalline ; the former fuses at 120, the 

 latter at 225. 



Iodine substitution-products. Monoiodophenol, 

 C 6 H 4 I.OH. When a mixture of iodine, iodic acid, and 

 phenol is dissolved in an excess of dilute caustic po- 

 tassa, there are produced two isomeric compounds, or- 

 thoiodophenol and metaiodophenol, of which only the or- 

 thoiodophenol is known in a pure condition. It is 

 also produced by hoiling diazoiodobenzene sulphate 

 with water. Flat, shiny needles. A third isomeric 

 modification, paraiodophenol, separates in the form of 

 fine, colorless, very stable needles when paradiazoiodo- 

 benzene, sulphate is boiled with water. Diiodophenol, 

 C 6 H 3 I 2 .OH. Is most easily obtained by adding iodine 

 and mercury oxide to an alcoholic solution of phenol. 

 Colorless needles, that sublime at 150. Triiodo- 

 phenol, C 6 H 2 I 3 .OH. Colorless needles ; fusing point, 

 156 ; not sublimable. 



Nitrosubstitution-products. Mononitrophenol, 

 C 6 H 4 (T0 2 ).OH. When phenol is added to dilute 

 nitric acid two isomeric compounds, nitrophenol and 

 isonitrophenot (orthonitrophenol), are formed ; of these 

 only the former is volatile with water vapor. Nitro- 

 phenol forms large prisms of a sulphur-yellow color; 

 sparingly soluble in water, easily soluble in alcohol; 

 fusing point, 45 ; boiling point, 214. Isonitrophenol 

 crystallizes in long, colorless needles that fuse at 110. 



Dinitrophenol, C 6 H 3 (ST0 2 ) 2 .OH. Is produced from 

 phenol by treatment with concentrated nitric acid, and 

 also by boiling dinitrochlor- or dinitrobrombenzene 

 with caustic potassa or sodium carbonate. Almost 

 colorless laminae or plates. Fusing point, 114. 



Trinitrophenol (Picric acid), C 6 H 2 (]Sr0 2 ) 3 .OIL Is 

 produced by the action of an excess of concentrated 

 nitric acid on phenol and numerous other bodies : ' 

 indigo, anilin, salicylic acid, several resins, etc.; and 

 by heating trinitrochlorbenzene with water, or more 



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