434 PHENOL AND PAKAKRESOL. [BOOK II. 



Physical Phenol, when pure, crystallises in the form of rhombic 



and chemical need i es . it melts at 40 42 C., and boils at 180 

 phenol (*- 18 9' 5 - . Jt is so^ble in 15 parts of water at 15 17 C. 

 boiic acid), It is easily soluble in alcohol, ether, and glycerin. 

 C 6 H 5 . OH. j n a q lieous solution, and in the absence of alcohol, 



phenol exhibits a violet reaction when treated with ferric chloride. 

 It also exhibits Millon's reaction. With bromine water it yields a 

 milky turbidity or a crystalline precipitate having the composition 

 C 6 H 2 Br 3 OBr. This body is soluble in solution of sodium hydrate, and 

 the solution is precipitated on the addition of hydrochloric acid, 

 which throws down tribromophenol, C 3 H 5 Br 3 OH. This compound 

 has a melting-point of 95 C. It contains ^72*5 per cent, of Br. 

 When boiled with Millon's reagent, an intense red colouration or a 

 red precipitate is observed. 



Physical Parakresol is much less soluble in water than phenol, 



and chemical It melts at 36 C. and boils at 198 C. 

 characters of Aqueous solutions of parakresol are coloured blue 



CH^H^'OH ky ferric chloride. With bromine it yields a crystalline 



3 ' 6 4 ' precipitate which presents the form of small scales and 

 not of needles 1 . When this precipitate is dissolved in alkalies and 

 precipitated with hydrochloric acid, the body is found to be tribromo- 

 phenol. It would appear, according to Baumann and Brieger, that 

 under the influence of bromine, parakresol, like phenol, yields 

 tribromo-phenol, CO 2 being evolved, as shewn in the following 

 equation : 



Parakresol. 



= C 6 H 2 Br 3 OH + C0 2 + 9HBr 2 . 



Tribromophenol. 



identification In order to separate and identify phenol and para- 

 of phenol and kresol these bodies must be converted into the respective 

 parakresol. sulphates 



ca 



HSO 



by heating on the warm bath for an hour with an equal volume 

 of strong sulphuric acid. The barium salts of these acids can be 

 separated, the compound of parakresolsulphuric acid being almost 

 insoluble, whilst that of paraphenolsulphuric acid is soluble 3 . 



1 Baumann und Brieger, Ber. d. d. chem. Gesellsch. 1879, p. 804 : Weyl, Zeitschrift 

 fur physiolog. Chemie, Vol. in. (1879), p. 319. 



2 E. Baumann und L. Brieger, 'Ueber die Entstehung von Kresolen bei der Faulniss,' 

 Zeitsch.f.phys. Chem., Vol. in. (1879), p. 149. 



3 For further details the reader is referred to Baumann and Brieger's paper in the 



