215 



compounds which are contained in it. Th< behaviour of such a 

 fcii-titil nice in ic compound, as it is called, is th -n quite analogous 

 to that of a raccmic compound above or below its transition 



ure, except that the typical symmetry of the solubility-relation^ 

 is lost, because the pseudo-racemic compound no longer splits up 

 into components which are mirror-images of each other. 



The first example of this kind was found by Ladenburg 1 ) in 

 the case of strychnine-racemate, and of the salt formed from quinine 

 and methylsuccinic acid. The first substance appears at 30 C. to 

 have a (maximum) transi- 

 tion-temperature. Above 30 

 C. therefore it is split up 

 into strychnine-d-tartrate and 

 strychnine-l-tartrate . 



The solubility-relations 

 existing in such cases were 

 first fully understood and 

 explained by BakhuisRoo- f, 

 zeboom 2 ). The symmetry 

 of our former figures is of 

 course now lost (fig. /jp), 

 while the solubility-curve TS ^ 

 for the mixture no longer Fig. 159. 



coincides with OA, because 



of the difference in solubility of the dextro-, and laevogyratory 

 component. QT might even lie wholly to the right of OA, and in 

 that case the temperature-range MT in which no solutions of the 

 pure racemoid can exist, will become yet greater, the racemoid 

 being continually decomposed by gradual precipitation of the lae- 

 vogyratory salt, until at the transition-temperature corresponding 

 to T, the fission is finally completed. 



1) A. Ladenburg and collaborators: Ber. d. d. Chem. Ges. 27. 75. (1884); 

 31. 524, 937, 1969. (1898); 82. 50. (1899); 86. 1649. (1903); 40. 2279. (1907); 

 41. 966. (1908); Ann. der Chemie 364. 227. (1909); E. Fischer, Ber. d. d. Chem. 

 Ges. 27. 3225. (1894). F. S. Kipping, Journ. Chem. Soc. London 95. 408 

 (1909); M. Levi-Malvino and A. Mannino, Atti Rend. Acad. Lincei Roma 

 (5). 18. //. 144. (1909); A. Windaus and C. Resau, Ber. d. d. Chem. Gs. 

 48. 861. (1915). F. W. Kiister, Ber. d. d. Chem. Ges. 81. 1847. (1898). A. 

 Findlay and E. M. Hickmans, Joum. Chem. Soc. London, 91. 905. (1907); 95- 

 1386. (1909). H. Dutilh, Proceed. Kon. Acad. v. Wet. Amsterdam, 12.393. (1910). 



-') H. W. Bakhuis Roozeboom, Zeits. f. phys. Chemie 28. 502. (1898). 



