CHEMISTRY. 337 



On the Reactions of Both the Ions and the Molecules of Acids, Bases, and Salts. A Reinter- 

 pretation of the Reactions of Sodium Methylate and Sodium Ethylate with 

 1, 2-Dinitrobenzene, 1, 2, 4-Dinitiochlorbenzene, and 1, 2, 4-Dinitrobrombenzene. 

 By S. F. Acree. Twenty-second Communication on Catalysis. 



In this article the writer has shown that the data of Bruyn, Lulofs, and 

 Steger can be reinterpreted as a reaction of the dinitrobenzene and of the halo- 

 genated dinitrobenzene with both the methylate (ethjdate) ions and the non- 

 ionized sodium methylate (ethylate). 



The work on the theory of the tautomerism of the phenolphthaleins 

 has been advanced very materially by Mr. E. C. White, who has found 

 in phenolsulphonphthalein a substance which nearly ideally fits the 

 requirements for this study. According to the former theory of others, 

 phenolphthalein, which is colorless and practically entirely in the 

 lactoid state (A), is in equilibrium with a trace of the quinoid form (B), 

 which changes into a quinoid monobasic salt (C), the quinone group 

 being responsible alone for the color change. 



(C6H4COO) C (C6H40H)2^^(HOOCC6H4) C ( : C6H4 : 0) (C6H4OH) 



+ NaOH:;=^ 

 (A) (B) 



(NaOOCC6H4) C (:C6H4:0) (C6H4OH ) + H2O + NaOH^=^ 



(C) 



(NaOOCC6H4) C ( : C6H4 : OHQH^a) + 2H2O 



I I 



(D) 



According to our theory (C) is only faintly colored and must first 

 react with more alkali and form the dibasic quinonephenolate salt (D) 

 before the chief color change occurs. Up to this time it has been impos- 

 sible to observe both of these steps taking place successively because 

 the COONa group of (C) greatly suppresses the ionization of the COOH 

 group of (B) and makes it possible for the NaOH to be partitioned 

 between the COOH groups and OH groups and give rise to (C) and 

 (D) simultaneously. 



Phenolsulphonphthalein is red in the solid state and yellow in solu- 

 tion and hence exists appreciably in both forms (E) and (F). When 

 sodium hydroxide is added to this 



(C6H4SO3) C (C6H40H)2^^(H03SC6H4) C (iCe H4 : 0) (C6H4OH) 



+ NaOH^=^ 

 (E) (F) yeUow 



(Na03SC6H4) C (:C6H4:0) (C6H4OH) + H2O + NaOH^=i 

 (G) yellow 



(Na03SC6H4) C (: C6H4: OHC^IWNa) -|- 2H2O 

 I I 



(H) deep red 



