COMPLEX AROMATIC COMPOUNDS. 



In addition to benzene and its substitution products, compounds 

 in which only one benzene ring is present, numerous compounds are 

 known which contain two or more benzene nuclei. These nuclei may 

 be joined by means of one or more carbon atoms, or they may be 

 joined together directly. 



Diphenylmethane. 



apw _X X " X X Diphenylmethane is the first and chief 



2 | example of a complex aromatic compound in 



I I which two benzene rings are united by a 



^xx^ carbon atom. 



It is obtained by heating benzene with benzyl chloride in the presence of 

 aluminium chloride : 



C 6 H 6 CH 2 C1 + C 6 H 6 = HC1 + C 6 H 6 . CH 2 . C 6 H B . 



Diphenylmethane is a crystalline solid, which melts at 26-5. It closely 

 resembles benzene in forming nitro and other derivatives. On oxidation with 

 chromic acid it yields benzophenone, C 6 H 5 . CO . C 6 H 5 . 



Triphenylmethane. 



.xx. Triphenylmethane contains three ben- 



| j zene nuclei joined to one carbon atom, 



and is obtained by heating benzal chloride 

 ! ^x^x^ with benzene in the presence of aluminium 

 chloride : 



/C 6 H 8 

 C 6 H B . CHCLj + 2C 6 H 6 = 2 HC1 + C 6 H 5 . CH\ 



X C B H 5 



or by heating benzene with chloroform in the .presence of aluminium 

 chloride : 



/C fi H 6 

 3 C 6 H 6 + CHC1 3 = 3 HC1 + C 6 H B . CH 



Triphenylmethane is a colourless solid, which melts at 92 and boils at 

 358. It is not easily soluble in cold alcohol, but dissolves easily in ether 

 and benzene. 



