26 



The Philippine Journal of Science 



1913 



phenol is greatly weakened by the introduction of the COOCH 3 

 group in the ortho position, and that the affinity constant of 

 the ester is probably one-tenth that of phenol are essentially 

 correct. 



Naumann, Miiller, and Lantelme 18 have determined by the 

 distillation method the percentage of hydrolysis of sodium 

 phenylate at 100°, and the hydrolysis constant calculated from 

 their values gives about the average 1.5-10" 3 . It is possible 

 that at 30° the temperature coefficient will reduce this figure 

 to less than one-tenth of its value, in agreement with that given 

 by Walker; 19 namely, 0.85-10-* at 25°. 



Since the solubility of this ester at 100° was required in the 

 study of the hydrolysis at this temperature, it was determined 

 as follows: 



One liter of pure water was boiled for thirty minutes with an 

 excess of methyl salicylate. The ebullition was stopped and the 

 ester then almost entirely settled to the bottom, leaving a small 

 quantity floating. Small samples were syphoned into small 

 weighed flasks, neutralized, and then saponified for two and 

 one-half to three hours and titrated, employing phenolphthalein 

 as indicator. The results are tabulated as follows: 



Table XI. — The solubility of methyl salicylate in water at 100". 



Weight 



of 

 sample. 



N/10 



NaOH 



required. 



Ester in 

 solution. 



Molar 



solubility=e. 



Average. 



Grams. 

 61.19 

 60.94 

 53.20 

 51.96 



7.06 

 6.48 



7.45 

 5.60 



Per cent. 

 0.1754 

 0. 1615 

 0.2128 

 0.1638 



[ 0. 0117 



MEASUREMENTS AT 100 



The hydrolysis was carried on in small flasks fitted with 

 return condensers. Small quantities of methyl salicylate were 

 from time to time added to the boiling solution, in order to 

 avoid the presence of great excesses of the ester which would 

 interfere with the accurate determination of the salicylic acid 

 in the aqueous solution. Small quantities of the water solution 

 were removed at intervals, and the salicylic acid determined 

 by the colorimetric method. 



"Journ. f. prakt. Chem. (1907), n. s. 75, 68. 



19 Introduction to Physical Chemistry. London (1910), 36. 



