6 OPTICAL ACTIVATION 



prepared by catalysis, if possible, the oDtically active isomeric 

 bromcamphors and broincaniphor-carboxylic acids, from the 

 racemic bromcamphor-carboxylic acid. This acid is found to 

 be much better suited for catalytic asymmetric division than 

 camphor-carboxylic acid, for which the former ucid the quantity 

 of catalyst, calculated in equivalents, can be very much smaller 

 than that of the decomposed substrate. 



PREPARATIONS. 



Inactive solvent: Acetophenone was obtained from G. F. 

 Kahlbaum, and before being used it was- dried over anhydrous 

 sodium sulphate and redistilled. 



Acids: d-, 1-, and iii-bromcamphor-carboxylic acids. 

 These acids were prepared from the corresponding oamphor- 

 carboxylic acids. As difficulties had been experienced in 

 obtaining perfectly pure bromcamphor-carboxylic acids, it was 

 thought best to start with absolutely pure camphor-carboxylic 

 acids. These were prepared according to the sodium amide 1 

 method of Bruhl 2 . The inactive acid was prepared from 

 synthetic camphor, (very kindly presented by the chemischen 

 Fabrik auf Aktien vorni. E. Schering, Berlin), after its slight 

 dextro rotation had been compensated by the addition of the 

 requisite amount of 1- camphor. The best yields of camphor 

 carboxylic acid were obtained when the sodium amide was 

 finely divided, the temperature high (110 -140), and the 

 stirring as rapid as possible. It was found that the sodium 

 amide could be conveniently ground up in an ordinary mortar 

 under toluene. By using toluene or xylene for the reaction 

 liquid, a favourable temperature was obtained. In order to 

 stir the mixture rapidly, and also to lessen the chance of 

 breakage, owing .to the tendency of the sodium amide to adhere 

 to the sides of the glass flask, the use of an iron vessel was tried. 

 It was found, howover, that the amide acted on the iron to a 

 certain extent, a substance resembling Prussian Blue being 

 formed, and that it required several crystallisations to obtain 



1. For the fresh sodium amide I am indebted to the Deutschen Gold- 

 und Silberscheideanstalt, Frankfort, a/M. 



2. Bruhl, J. W.: Ber. d. deutsch. chem. Ges., 36, 1305, (1903). 



