26 OPTICAL ACTIVATIOX 



was sufficient to remove the 0.1000 -ram of cliiiiin used for 

 the activation. As further proof of the complete removal of 

 the quinine, no green colouration was obtained on shaking the 

 last HCr extract with bromine water and ammonia (a very 

 delicate test for quinine). The undecomposed acid- was then 

 removed from the acetophenone bv shaking with dilu-te 

 potassium hydroxide solution. As water solutions separate 

 only very slowly from acetophenone (the sp. g. is almost the 

 same for the two), in most cases they were separated by means 

 of a centrifugal machine. After removal of -the acid the 

 aceophenone solution was dried with anhydrous sodium sul- 

 phate. Its volume was 50 ccm., 5 ccm. having been lost in the 

 separation oj)erations. 16 ccm. of this solution were placed 

 in a 2 dcm. tube and its rotation was found to be: 

 « ^ — O^.Tl"'^. In order to calculate -the amount of active 

 bromcamphor in the acetophenone solution, the specific 

 rotation of bromcamphor in acetophenone was measured. 

 0.5000 gram of cl- bromcamphor, dissolved to 10 ccm. in 

 acetophenone. gave, in a 1 dcm. tube, a rotation of: + 6°.94, 

 corresponding therefore to [a]^ =^ 138°. 8. The weight of 

 bromcamphor contained in v = 55 ccm. of the above aceto- 

 phenone is 



a 0,71 



2'= V r— n = oo 



= 0,141 cr. 



[all -^ 188,8-2 



From the kinetic data it is found that, at the end of 68 

 minutes from the commencement of the reaction, 1.569 g. 

 of 1- bromcamphor and 1.176 g. of d- bromcamphor should 

 be found. The excess of 1- bromcamphor over d- brom- 

 camphor being, therefore 0.420 g. Perhaps the difference 

 between the amount of active bromcamphor calculaled from 

 the kinetic data and that actually found, may be due to the 

 occurrence of racemization. 



*The mean error in reading: the polariscope was 0°.01 — 0°.02. 



