322 



Scientific Proceedings. Royal Dublin Society. 



[Comptes Eendus, cli (1909), p. 492] by passing the vapour of phenol over 

 heated thoria. For the piirpose of the present investigation the oxide was 

 obtained in fair yield (15 per cent.) by heating a mixture of litharge and 

 phenol for eight hours, and then subjecting the product to destructive 

 distillation [Compare Galewsky, Liebig's Annalen, cclxiv (1891), p. 189]. 



The nitration of diphenylene oxide has been already attempted, but with 

 somewhat inconsistent results. Borsche and Bothe [Ber. Dtsch. Chem. Soc, xli 

 (1908), p. 1940], by the action of fuming nitric acid on a solution of the oxide 

 in glacial acetic acid, obtained a mononitro derivative, melting at 181-182° C. 

 Mailhe [Comptes Rendus, eliv (1912), p. 1515] states that this compound melts 

 at 175° C. ; but our product was found to have the same melting-point as that 

 of the former investigators. Borsche and Bothe were of opinion {loc. cit.) that 

 this body was 3-nitrodiphenylene oxide^, and this contention is borne out by 

 considerations based on the theory of induced alternate polarities recently put 

 forward [Robinson and Kermack, Journ. Chem. Soc, cxxi (1922), p. 427; 

 Lapworth, ibid., p. 416].. 



Galewsky {loc. cit., p. 129) attempted to prepare a mononitro derivative 

 by direct nitration of diphenylene oxide, but was not successful, a dinitro 

 compound only being obtained. Hoffmeister [Liebig's Annalen, clix (1871), 

 p. 214] described a dinitrodiphenylene oxide, melting about 200° C. This 

 substance was probably an impure form of the dinitrodiphenylene oxide, 

 melting at 245° C, prepared by Mailhe [loc. cit.; see also Bull. Soc. Chim. 

 (1912), i, p. 1011] in a similar manner, and which he considered to be 3-6-dinitro- 

 diphenylene oxide. This assumption is also in accordance with the theory of 

 alternate polarities. Mailhe also claimed {loc. cit.) to have obtained by nitration 

 a tetranitro compound, melting at 168° C, a pentanitro compound, melting at 

 122° C, and a hexanitro derivative, melting at 135° C, but he afterwards stated 

 that the pentanitro and the hexanitro derivatives did not exist. He described 

 also a trinitrodiphenylene oxide, melting at 142-143° C, and a tetranitro- 

 diphenylene oxide, melting at 172° C. 



The state of our knowledge concerning the nitro deri^'atives of diphenylene 

 oxide before the present investigation was undertaken may be summarised as 

 follows : — 



' The nomenclature adopted in this communication is based on the following formula :- 



s 1 



/\ / \ /\ 

 -^ V V \2 



6 



4 



