H 



XI, A, 2 Brill: Diethylsuccinosuccinate, II 65 



DIKETOHEXAMETHYLENE 

 



H II H 



H II H 

 



Diketohexamethylene was made by the method described by 

 Baeyer." After repeated crystallizations it melted at 78°. It 

 was examined immediately after having been crystallized, as 

 it was noticed that on standing in a dessicator the compound 

 slowly changed from pure white to a yellow tint. Titrated with 

 bromine solution in accordance with the directions of Kurt H. 

 Meyer," it reacted for practically the pure keto form in alcohol 

 solution. 



In alcohol solution a very refrangible band appeared in ap- 

 proximately molar solution at 1/A=3,500. 



P-HYDROXYQUINONE 

 



H- 



/\-0H 

 — H 



II 

 



Kehrman " describes a method for the preparation of hydroxy- 

 quinone by treating dianilinoquinone with a mixture of 3 parts 

 of concentrated sulphuric acid and 2 parts of alcohol. However, 

 as the yields obtained by me by the use of this method were 

 exceedingly small, a modified method was adopted. Much better 

 yields were obtained by warming dianilinoquinone in a tenth 

 normal alcoholic potash solution on the steam bath under a 

 reflux condenser until it had gone into solution and the solution 

 had become a certain shade of red easily detected by experience. 

 This usually required from three to five hours' warming. Al- 

 cohol of approximately 85 per cent strength was more influential 

 to good yields than stronger alcohol. A large part of the alcohol 



"Ibid. (1894), 278, 91. 

 " Loc. cit. 



"Ber. d. deutsch. chem. Ges. (1890), 23, 903. 

 139112 2 



