282 



If so, the final equilibrium wil not be influenced by the 

 presence of such a solvent, and there seems to be only a slight 

 chance that any positive result may be expected from the experi- 

 ments indicated above. 



Secondly, the solvent may really take an active part in the 

 reaction, for instance by means of the intermediate formation 

 of instable compounds with the molecules of the re-acting sub- 

 stances. In such cases also an influence upon the final state of 

 equilibrium will be present, or at least, may be present. If 

 B represent the solvent, such a case may occur when there is 

 an appreciable difference in solubility between the thus formed 

 compounds AB n and A'B n in the optically active medium. But 

 as we have seen in the preceding pages, this difference, if present 

 at all, seems in general not to be very great, and even in this 

 more favorable second case, therefore, no great expectations of 

 positive results in experiments of the above mentioned kind 

 should be had. 



Experiments to demonstrate the existence of such differences 

 in reaction-velocity, if the processes go on in a dissymmetrical 

 medium, have already been made from time to time. 



Thus B o y d x ) tried to reduce benzoyl- formic acid by means of 

 hydrogen in aqueous solutions of dextrogymtory tartaric, or laevo- 

 gyratory mandelic acid; the mandelic acid produced in this reduc- 

 tion was completely inactive, or its activity corresponded to that 

 of the active acid used in excess. 



Kipping 2 ) studied the reaction between KCN or HCN, 

 and benzaldehyde, in an alcoholic solution of optically active 

 camphor, or the reduction of pyruvic acid in an aqueous solution 

 of d-glycose; the results were equally negative. E. and O. Wede- 

 kind 3 ) investigated the addition of allyl-iodide to methyl-benzyl- 

 aniline in optically active limonene as a solvent, but they could 

 only obtain optically wactive products, and the same was true, 

 when they used as solvents l-menthol or l-chloro-methyl-menthyl-ether. 



From these experiments it may be concluded that it is highly 

 improbable that a positive difference in reaction-velocity would 

 be observed in the case of both antipodes, when optically active 



1) D. R. Bo yd, Inaug. Dissert. Heidelberg, (1896). 



2) F. S. Kipping, Proceed. Chem. Soc. 16. 226. (1900). 



3) E. and O. Wedekind, Ber. d. d. Chem. Ges. 41. 456. (1908). 



