the Constitution of Benzene. 433 



And if we examine the properties of naphthalene we do not 

 find that it sustains the character of a benzene derivative. 

 The production of phthalic acid from it is not in favour of 

 such a view any more than the production of terephthalic 

 acid from succinosuccinic ether is in favour of this latter 

 body containing a benzene nucleus. 



Against the notion that naphthalene consists of two benzene 

 nuclei we have the fact of the comparatively easy oxidation 

 of one of the nuclei giving phthalic acid or naphthoquinone,, 

 contrasted with the difficulty of so oxidizing benzene and 



compared with the easy oxidation of anthracene, where there* 

 is no supposition of the benzene nature of the groups 

 oxidized. Again, we have the easy formation of addition 

 products, such as tetrahydronaphthalene, contrasted with the 

 difficulty of so reducing benzene. 



And these reactions receive a natural explanation when 

 naphthalene is considered as an unsaturated fatty compound. 

 For it will be noticed that only one of the hexagons of the 

 naphthalene formula is attacked; the unattacked hexagon may 

 then be regarded as passing into the peculiar benzene con- 

 dition which renders it less susceptible of further attack. 



Thus we have phthalic acid : — 



CH 

 HC^C— COOH 



VA 



HC , C— COOH 

 \/ 

 CH 



fig. 12. 



