( «64 ) 



subsequcnr nitration of the henzeiie o-nitrotluoride. This, thcrofoi-o, 

 amounts to 8"/„, corresponding- witli 6.1"/,, of ort ho compound. Accor- 

 diuf? to the al)ove the eouipositioii of the uilratioii product is therefore : 



6.17,, l)enzene ortho nitro-lhu»ri(UM Heing foruied hy nitration of hen- 



4.1Y„ „ mcta „ ' zene lhiori(h' at ()" ^vitil tiie com-en- 



89.8"/,, ,, para ,, Mi-atiou of the acitl stated on p. (i62. 



The composition of tlie twice nitrated pi'oduct M'as found to be 

 i)"'„ of benzene dinitrofbioride, 4"/„ of meta- and 87"'„ of para com- 

 poun(h This was easily coiUrolhMl Im malcinii- an artilicial mixture 

 liaving this composition as all the three componejils were at disposal. 

 Its properties must then be identical witli that of the twice nitrated 

 product. And indeed, the solidifying poijit of such a mixture was 

 found to l»e 18\7 and 18. 9 whilst that of the said product Avas at 

 18°. 8. According to 1)1<',1''.k.man"s data'), the sp. gr. of the artilicial 

 mixture should amount to 1.2773, whereas 1.271)1 was found for the 

 twice nitrated product. This higher figure is, probably, to be attri- 

 buted to the fact that the coi-rections to be appbed are somewhat 

 uncertain so that the results could only be accurate to within about 

 !"/„. If this should cause a little excess of dinitro and a little deti- 

 ciency of meta compound, the si), gr. will be at once seriously 

 alfected, whilst the solidifying point does not i)ercei»libly alter. In 

 fact, an excess of 0.8''/„ of dinitro compound is sutHicient to explain 

 the diiference in the sp. gr. 



1 have also endeavoured to nitrate benzene tluoride at — 30°, 

 nsino- the same acid mixture employed in the nitration at 0''. On 

 adding the tluoride drop by drop to the acid cooled to that temperature 

 it dissolves with a dark brown colour causing but little rise in 

 temperature, just as had been observed in the nitration of benzene 

 bromide. After all the benzene fluoride had been added, the colour 

 o-radually began to fade and when the nitration vessel was removed 

 from the refrigerating mixture and its contents reached a temperature 

 of about — 20', the liquid soon became pale yellow and the temperature 

 rose to about -|- 10". It, therefore, appears that the velocity of 

 nitration at — 30' is already considerably retarded, as the intro- 

 duction of each drop of benzene fluoride at 0' is accompanied by 

 a very perceptible caloric effect. The solidifying point of the product 

 which was collected in the way described, was situated at lO.'^l, 

 from which it may be coiududed that it dilfers but little t'nnn the 

 product obtained by nitration 0\ This can only contain al)out 1";; 

 less of by-products. 



1) Sp. gr. meta 1.2532; para 1.2.j83: dinilro 1.4718, all at 84-.4S. 



