24 OPTICAL ACTIVATION 



All examiuatiou of the numbers in the f < iregoino- tables shows 

 that the influence of quinidine on the decomposition of d- and 

 1- bromcamphor-carboxylic acid is almost identical with the 

 effect produced by its isomer, quinine, on the decomposition of 

 1- and d- bromcamphor-carboxylic acids. The rate of 

 decomposition of the inactive acid lies about midway between 

 the rates for the d- and 1- acids. Further, the velocity of 

 the reaction and the ratio given in coluimi tive of the tables 

 show the maxium to which mention has already been made. 

 The progress of the reaction with time is shown graphically in 

 Fig. 3. 



Optical Actitatiox by Catalysis. 

 In the foregoing kinetic measurements on the decomposi- 

 •tion of bromcamphor-carboxylic acid in the presence of quinine 

 and quinidine, it has l^een found that there is a difference 

 between the rates of reaction of the two optical isomers. It 

 should be expected therefore, when the opticaUy in^active acid 

 is decomposed under the catalytic influence of an alkaloid and 

 the rea-ction stopped liefore the end, that the tivo antipodes 

 icoidd not he present in equivalent amounts, and that also the 

 newly formed bromcamphor, as well as the reniaimng unde- 

 composed hromcamphor-carhoxylic acid, would show optical 

 activity. In order to test whether optical activation could be 

 brought about by this means, cjuinine in one experiment, and 

 quinidine in another were used as catalysts. 



As the curves (fig. 2 and 3) illustrating the progress of 

 the reaction with time show, the difference between the already 

 decomposed (or still undecomiDosed) acid content of the two 

 isouiei-s grows steadily for a time, reaches a maximum, and 

 then falls off until, when the acid is all decomposed, it is 

 nothing as at the beginning of the reaction. In order to obtain 

 the greatest rotation it is evident -that the reaction must he 

 stopped at the moment when this difference is greatest. This 

 is readilv calculated from the curves. 



