30 SCIENCE PROGRESS 



Will stated that none of these compounds was formed in 

 the nitration of toluene, but Drew {Trans. Chem. Soc, 1920, 117, 

 161 5) found that 2 : 3 : 6-trinitrotoluene was produced to a 

 small extent in the nitration of m-nitrotoluene, while Mar- 

 queyrol, Koehler and Jovinet {Bull. Soc. Chim., 1920 [iv], 27, 

 420) also isolated a third trinitrotoluene from the nitration 

 products of m-nitrotoluene, but did not identify it. 



A quantitative study of the nitration of toluene by the 

 method of thermal analysis has now been published by Gibson, 

 Duckham and Fairbairn {Trans. Chem. Soc, 1922, 121, 270). 

 The mononitration of toluene, the nitration of the three nitro- 

 toluenes to dinitrotoluenes and the nitration of the latter to 

 trinitrotoluenes, have all been studied quantitatively and the 

 necessary binary and ternary fusion diagrams constructed. 



Under normal conditions, such as obtain in manufacture, 

 toluene on nitration gives a mixture containing 61 to 63 per 

 cent, of o-nitrotoluene, 33*5 to 32 per cent, of ^-nitrotoluene, 

 and 4*5 to 4*2 per cent, of m-nitrotoluene. Low temperature 

 nitration reduces slightly the amount of m-nitrotoluene, and 

 by nitration with nitric acid alone at 0° as little as 2-5 per cent. 

 of this compound is formed. o-Nitrotoluene on dinitration 

 gives a mixture of 66-6 parts of 2 : 4-dinitrotoluene and 

 33*3 parts of 2 : 6-dinitrotoluene ; _^-nitrotoluene gives 



2 : 4-dinitrotoluene only ; m-nitrotoluene gives a mixture 

 of approximately 55, 25, and 20 parts of 3:4-, 2:3-, and 



3 : 6-dinitrotoluenes respectively. On trinitration 2 : 4- 

 and 2 : 6-dinitrotoluenes give 2:4: 6-trinitrotoluene only ; 

 3 : 4-dinitrotoluene a mixture of 83 parts of 3:4:6- and 

 1 7 parts of 2:3: 4-trinitrotoluenes ; 2 : 3-dinitrotoluene a 

 mixture of 84 parts 2:3:4- and 16 parts of 2 : 3 : 6-trinitro- 

 toluenes ; 3 : 6-dinitrotoluene a mixture of 87 parts of 

 3:4:6- and 13 parts of 2 : 3 : 6-trinitrotoluenes. 



The nitration of toluene gives, therefore, the following 

 products in the various stages : 



Mononitrotoluenes. Dinitrotoluenes. Trinitrotoluenes, 



ortho- . 62 percent. 2 : 4- 74*8 per cent. 2:4 :6- 95-5 per cent, 



para- . 33-5,, ,, 2:6- 207 ,, ,. 3:4:6- 2-9 



meta- . 4-5,, „ 3:4- 2-5 ,, ,. 2:3:4- 1-3 



2:3- i-i ,, „ 2:3: 6- 0-3 



3 : 6- 0-9 ,, ,, 



Electronic Conception of Organic Compounds. — ^Two papers 

 have been published (Lapworth, Trans. Chem. Soc, 1922, 121, 

 416 ; Kermack and Robinson, ibid., 427) in which an attempt 

 is made to correlate a few of the reactions of organic chemistry 

 with the Thomson and Lewis-Langmuir theories of atomic 

 structure. It is impossible to do justice to this subject in a 

 short review, and readers must be referred to the original papers. 



f > > t 

 t* tt 



