Section III, 1918 [19] . Trans. R.S.C. 



The Compounds of Phenol and the Cresols with Pyridine {Abstract) 



By F. W. Skirrow and T. V. Binmore 



Presented by Dr. R. F. Ruttan, F.R.S.C. 



(Read May Meeting, 1918.) 



In continuation of the work of Hatcher and Skirrow (Journ. 

 Amer. Chem. Soc. XXXIX, 9, 1939, 1917) the authors have studied 

 the effect of excess of phenol and of pyridine respectively on the 

 dissociation of pyridine phenate CeHsOH C5H5N in benzene solution, 

 the dissociation being calculated from depression of freezing point data 

 on each of the four assumptions as to the simultaneous association of 

 the components and of the compound that were made in the earlier 

 paper. It is shown that on any of these assumptions the effect of 

 excess of phenol on the dissociation is much greater than the effect of 

 excess of pyridine, and thus that the equilibrium 



C6H5OHC5H5N -^ CeHsOH + C5H5N (1) 



can not be dominant. 



It is further pointed out that the form of the two curves represent- 

 ing the effect of excess of pyridine and excess of phenol on the dis- 

 sociation closely resembles the form of the two curves obtained 

 previously for the effect of excess of pyridine on the percentage ex- 

 traction of phenol by sodium hydroxide, and for the effect of excess of 

 phenol on the percentage extraction of pyridine by dilute sulphuric 

 acid. 



It was shown in the earlier paper that phenol and pyridine also 

 form a second compound (C6H50H)2 C5H5N. 

 The dissociation 



(C6H50H)2 C5H5N -^ 2C6H5OH -f C5H5N (2) 



was therefore next studied on lines similar to the above and the effect 

 of excess of phenol and of excess of pyridine on the dissociation deter- 

 mined. If this equilibrium was dominant we should expect that the 

 effect of pyridine on the dissociation would be proportional to the 

 concentration of the pyridine whilst the effect of excess of phenol 

 would be proportional to the square of the concentration of the phenol, 

 and the curves obtained should resemble those actually obtained for 

 equilibrium (1). 



It is found, however, that this is not the case, the effect of small 

 excesses of pyridine being actually greater than the effect of cor- 



