Action of Hydrated and Nonhydrated Salts on Saponification. 107 



strontium, and barium, although in the series lithium, sodium, and 

 potassium, lithium seems to be an exception. 



The curves for the methyl formate are of the same general character, 

 the only difference being that the curves are more extended, more being 

 above the curve for water, probably due to the larger amount of saponi- 

 fication. The curves for calcium bromide, barium bromide, and mag- 

 nesium sulphate with methyl formate do not appear to be exceptions, as 

 they fall above the curves for salts with no water of crystallization. 



Kellogg 1 found in the case of the halides of potassium that the chlo- 

 ride increased the reaction the most, the bromide less and the iodide 

 least, normal potassium iodide actually decreasing the velocity. This 

 apparently points to the fact that the anion plays an important part 

 in the total effect of the salt on the reaction velocity. With more 

 dilute solutions of potassium iodide (0.25N) the velocity of the reaction 

 is increased. Kellogg's curves for strontium chloride, calcium chloride, 

 and barium chloride show that the cation must also be taken into 

 account. A possible explanation of the behavior of barium bromide, 

 calcium bromide, etc., may be that the total effect due to these salts is 

 due to a combination between a cation tending to increase the velocity 

 and an anion tending to decrease the velocity. 



Kellogg 1 also finds that there is a concentration for each salt that 

 will produce the greatest increase in the velocity of the reaction. Still 

 further increase or decrease in the concentration from this point 

 diminishes the velocity of the reaction. 



The action of the apparent exceptions which manifested themselves 

 in the study of this problem, i. e., lithium nitrate, lithium bromide, 

 calcium bromide, etc., may be due to the concentration of maximum 

 saponification not having been reached, since these salts on dilution all 

 increase the velocity. It is altogether probable that had the dilution 

 been still farther increased, the apparent exceptions would have proved 

 not to be exceptions at all. This seems to be all the more true, in that 

 the curves of figure 10, where larger percentages of methyl formate are 

 saponified, show that barium bromide, calcium bromide, and magnesium 

 sulphate have greater effect than potassium chloride and sodium 

 bromide. Therefore, it is more than probable that with solutions 

 so dilute as to reach the dilution of maximum saponification, and with 

 a larger amount of ester saponified, most of the apparent exceptions in 

 figures 7 and 8 would no longer be exceptions, but we would have a 

 general relation between salts with water of crystallization and salts 

 without, the former increasing the velocity to a larger extent than the 

 latter, having a larger temperature coefficient and decreasing more 

 with dilution. 



We are not satisfied with the results with strontium bromide, and 

 hope in the near future to do more work with this salt. 



Uourn. Amer. Chem. Soc., 31, 886 (1909); 35, 396 (1913). 



