Structure of Simpler Organic Compounds. 155 



prepared either by heating aniline with the alkyl halogen 

 compounds (compare preparation of secondary and tertiary 

 amines, p. 124 and seq.) or by heating aniline to 200 250, 

 with a mixture of the alcohol and hydrochloric acid 



C,H 5 -NH 2 HC1 + CH 3 .OH = C 6 H 5 -NH(CH 3 )HC1 + E^O 

 C 6 H 6 .NH 2 -HC1 + 2CH 3 -OH = C 6 H 5 N(CH 3 ) a HCl + H 2 



The general properties of aromatic amines, apart from their 

 ready formation of diazonium salts, are not very different 

 from those of the aliphatic derivatives. 



Phenols. 



Phenol or Carbolic Acid, C 6 H 5 OH. This substance 

 can be prepared from benzene by nitrating first to produce 

 nitrobenzene, which substance is then reduced to aniline, 

 which on treatment with nitrous acid yields phenol. It 

 can also be prepared by treating potassium benzene 

 sulphonate with potassium hydroxide. It is obtained on 

 a large scale from that portion of the coal-tar distillate 

 which boils between 170 and 230. This fraction also 

 contains another hydrocarbon, naphthalene, which sepa- 

 rates in a crystalline form on cooling. The phenol is 

 extracted by alkalis from the oily residue pressed out 

 from these crystals ; by virtue of its phenolic char- 

 acter (see p. 146), it dissolves in the alkali forming a salt. 

 From the solution so obtained the free phenol or carbolic 

 acid separates on acidification. Phenol is also found in 

 small quantities in urine. It is a colourless crystalline 

 substance, melting point 42, boiling point 183, which is 

 volatile in steam and turns pink on exposure to air. It 

 forms ethers of the type C 6 H 5 OR, in a similar way to 

 the aliphatic alcohols. 



Cresols (o-, w-, p-) are the next higher homologues of 

 phenol, having the formula C 6 H 4 (CH 3 XOH). They also 



