ON QUINONE. — WALLACE. 



309 



The method of separation was by no means complete, bat 

 nearly 2 grams of diphenyl were obtained. 



Discussion. 



The organo-magnesium halide quinone compounds, which 

 form with such energy on the addition of quinone to the 

 organo-magnesium halide, are not stable, but decompose when 

 exposed to the air. The bromide is blue and the iodide is 

 green. Their formation is possibly in accordance with the 

 following equation : 



I. CH\ /CH 



\ c-o-o-c C +- f^ %• ^'^ = 



CH 

 CH 



\/ 



COMgX 

 R 





. R \y 

 - COMgX / \ 



CH 

 CH 



Two molecules of the organo-magnesium halide are used to 

 each molecule of quinone. 



The foraiation of the quinhydrone may be explained by 

 the production first of hydroquinone, as shown in the following 

 equation : 



II. CH\ /COMgX. . R /CH HOH 



CH ^ "^ R / ^ COMgR / \ CH HOH 



OH OH 

 CH\ / //CH 



\ C - C <r + Mg(OH), + MgBr, -F R - R 



CH "^^ ^ CH 



The hydroquinone then reacts with the unattacked quinone, 

 the reaction being expressed by the following equation : 

 III. CeH.COH), + C6H4O2 = [C,H,(OH).. + CoH A] 



The production of diphenyl in the action of phenylma^- 

 nesium bromide quinone is evidence in support of the reaction 

 as given in equation II. 



