viii, a, i Gibbs, Williams, Galajikian: Methyl Salicylate IV 



Table X. — The hydrolysis of methyl salicylate in aqueous solution. 



Second series.* 



Cell No. S. Constants 0.1761. Temperature 30°. 



25 



1 



3 



7 



8 



9 



11 



t 



60' 



R. 



K=CR. 



f-103 



salicylic 

 acid. 



X 



methyl 

 salicylate. 



*H=f t - 



70 



117 



429 



669 



934 



1,346 



1,896 



2,926 



11,000 

 7,800 

 6,700 

 6,100 

 4,300 

 2,900 

 1,970 

 1,150 



0. 0301601 

 0. 0302257 

 0. 0302628 

 0. 0302887 

 0. 0304095 

 0. 0306072 

 0. 0308938 

 0. 0315310 









17,000 

 14,700 

 13, 700 

 9,600 

 6,400 

 4,100 

 2,200 



0. 030588 

 0. O3O68O 

 0. 030730 

 0. 031042 

 0. 031563 

 0. 032439 

 0. 034546 





5.3-10—7 

 3.6-10—7 

 3.7-10—7 

 3.9-10—7 

 4.3-10—7 

 5.2-10—7 







4.3-10—7 









• The column numbers correspond to those in Table IX. 



Great accuracy cannot be claimed for K H for the reasons that 

 the action of the solution upon the glass and the method 

 employed for estimating the concentrations in column 8 will 

 introduce unavoidable errors. The corrections for the conduc- 

 tivity of the water and that of the dissolved methyl salicylate are 

 slight and have less influence than the former causes for inac- 

 curacy. Slight changes in the temperature for such a long 

 period of time were unavoidable, and the high temperature 

 coefficient, which will be shown later to be one of the factors 

 of this reaction, introduces a considerable source of error. On 

 the whole, the approximation of Kh is very satisfactory under 

 the circumstances, and the decreasing values may be due to the 

 action upon the glass which is greatest at the beginning. 



The value of K A) the affinity constant of the methyl ester of 

 salicylic acid, is problematical and is about the magnitude 10 -11 . 

 Calculated from the hydrolysis constant of the sodium salt, 0.001, 

 as previously determined, the value is 



1-2=10-14 



10-3 



=K=1.2-10-». 



This value practically agrees with that obtained after shaking 

 the ester with water for three or four hours. 



Goldschmidt and Scholz's statements that the hydrolytic con- 

 stant of sodium methyl salicylate, 0.001, is considerably larger 

 than that of sodium phenylate, that the acid character of the 



