16 OPTICAL ACTIVATION 



The mean value for Tc is 0.0121 at 80, 0.00503 at 70, and 

 0.00212 at 60. From these numbers the -temperature co- 

 efficient for two intervals of ten degrees each may be calculated. 

 Between 60 and 70 it is 2.37 and between 70. and 80 it is 

 2.40. 



From the van't Hoff-Arrhenius equation 

 dink A 

 ~dT~ ~T" 

 we obtain by integration the equation 



0,4343 k 2 T,T 2 



and from -this the value for A may be calculated. By substi- 

 tuting the value of the ratio . - in the foregoing equation, A 



K 70 o 



is found to be 10600. while with the ratio-r A is found to 



"60 



be 9854. The mean difference between these two values is 

 3.5 per cent. 



i 



I 



2. Decomposition of Bromcamphor-carboxylic Acid at 40 in 

 the Presence of Quinine and Quinidine. 



a. Quinine. 



Pure quinine was obtained from C. F. Khalbaum. After 

 being dried for two hours its melting point was taken and found 

 to be 171. 5 172. 



dx 



In the following tables =- represents the rate of decomposi- 

 tion of the acid, and C m the mean concentration of the acid ; 

 the other symbols have the same meaning previously indicated. 



