203 



vidrinlv l-i t \\.-rn 8 and !."> ' .uul tin- formation of tin- race- 

 at<- hom tin- antij>oili -> niiiM be an riidotlu-rmir reaction 

 A -imilar case 1 ) must be the spontaneous li>sion of tin- tri< linn 

 ..id of dimctliyl-dwxyi[lntnric acid: CH.,[C(()//)(( '!/.,).((. ( )<>ll)\ 

 to it-- triclinic active components, when rx^tallisin^ from a solution 



in ether; from an aqueous solution the enantiomorphous salts could 



not be obtained however, -- which proves that tin -]>< < ial nature 

 f the solvent also plays a role in the matter. 

 For ammonium-bimedaU the transition-temperature wa> <1 

 incd by Ken rick *) at 75 C. He was also the first who demon- 

 trated that in the sphere of stable occurrence of the racemate it- 

 lubility is influenced by the addition of one of the two compon< 

 3. The relations which exist in these and similar cases with 

 spect to the solubility of the v 



:omponents and the racemic 



compound, were elucidated by 



Bakhuis Roozeboom 2 ) 



in 1899. 

 The graphs of fig. 157 and 



J 58 gi ye a n easy survey of these 



relations. On the axis OX the 



(solubility of the dextrogyratory 

 component is represented by 

 Oa, on the axis OY that of the 

 laevogyratory component by 

 Ob. The curve amb is the solu- 

 bility-curve for a temperature 

 of t C., which in fig. 157 is 



thought above, in fig. 158 below the transition-temperature of the 

 racemate, because of the fact that fig. is 7 is drawn for the case 

 that the transition-temperature is a maximum temperature, in 

 /* J 57 a minimum temperature foi the racemate, in the sense 

 explained above. The solid phases in equilibrium with the saturated 

 solutions amb, are here the dextro-, and the laevogyratory compo- 

 nents. 



ft- 



Fig. 157. 





1) N. Zelinsky (Cryst. Invest, by R. Prendel), Her. d. d. Chem. Ges. 24. 

 4014. (1891). 



-) F. B. Kenrick, Her. d. d. Chem. Ges. 80. 1794. (1897); J. H. Van 't Hoff 

 and H. M. Dawson, Ber. d. d. Chem. Ges. 81. 528. (1898). 



8) H. W. Bakhuis Roozeboom, Zeits. f. phys. Chemie, 28. 494. (1899). 





