OF ARTS AND SCIENCES. 117 



Salts of Curcumin. 



In taking up the study of this subject we were at first attracted 

 to the lead salt by the analyses and descriptions of Ivanow-Gajewsky 

 and Daube ; but, after several experiments, we decided that it was too 

 indefinite a substance to throw much liglit upon the nature of cur- 

 cumin, and accordingly turned our attention to the potassium salts, 

 which at first did not seem promising, but on proper treatment have 

 yielded satisfactory results. Before describing these, however, we 

 will say, that there seem to be at least two lead salts, as we have 

 obtained a dark claret precipitate and also a flame-colored one. 

 The most [)romising method of preparation seemed to be boiling cur- 

 cumin witli precipitated calcic carbonate and water, and adding 

 plumbic acetate to the filtrate ; in this way the flame-colored salt was 

 obtained. 



A\'e liave succeeded in obtaining two potassium salts, containing one 

 and two atoms of potassium respectively. 



Dipotassic Salt of Curcumin ICjCj^Hj.^O^. 



This was made by adding a large excess of a strong alcoholic solu- 

 tion of potassic hydrate to a hot saturated solution of curcumin in alco- 

 hol ; if the solutions are strong enough, flame-colored crystals of the 

 salt are deposited on cooling; if this is not the case, it can be precipi- 

 tated by addition of ether. If an insufficient amount of potassic 

 hydrate is used, a dark red solution of the monopotassic salt is formed, 

 which becomes lighter on the addition of more potassic hydrate as 

 the second atom of potassium is taken up. The salt was crystallized 

 from boiling alcohol to vvhicli a few drops of ether had been added, 

 washed with a mixture of alcohol and ether, then with ether alone, 

 pressed on filter-paper, and dried as rapidly as possible in a steam- 

 drying closet containing some potassic hydrate. 



0.71 G8 gr. of the salt gave, heated with sulphuric acid, 0.3824 gr. of 



lv,SO,. 

 0.2675 gr. gave 0.1 4o9 gr. of ICSO^. 



Calculated for CiiHjoKoO^ Found. 



Potassium 24.27 23.95 24.48 



If curcumin had the formula CigHuO^ the dipotassic salt would 



contain, 



Potassium 22.46. 



