232 Willstättcr's Rescarchcs on Chlorophyll [Jan. 



(Nutsche). The leaf meal is placed on the funnel, moistened with 

 the solvent, allowed to stand about five minutes, sucked off and the 

 Operation repeated, using for each the same volume of solvent as 

 above, about 1.5 to 2 liters per kilo. The yield of Chlorophyll in- 

 creases with the time of extraction : after 15 minutes, it is 2.9 gm. 

 per kilo; after 2 hours, 4.4 gm.; after 3 days (quantitative estima- 

 tion), 7.1 gm. The method as actually employed is the following: 

 2 kilos of dry meal are put on the filter, moistened with 2 liters of 

 80 percent acetone and then 4 to 4.5 liters added, a liter at a time, 

 with stirring, finally filtering completely from the decolorized meal. 

 This method is better than the one formerly used where 96 percent 

 alcohol was the solvent. 



Purification of Chlorophyll extracts.^^ The Chlorophyll extract 

 obtained as above with 80 percent acetone is poured into 4 liters of 

 petroleum ether (d. 0.64-0.66, Kahlbaum), one-half liter of water 

 added and the mixture shaken. The Chlorophyll goes into the 

 petroleum ether. After removing the aqueous acetone layer, the 

 petroleum ether is washed twice with i liter of 80 percent acetone 

 and the acetone partially removed by washing four times with 500 

 c.c. of water. All the acetone must not be removed or the Chloro- 

 phyll will be precipitated. Xanthophyll is then removed by washing 

 the petroleum ether three to five times with 2 liters of 80 percent 

 methyl alcohol. The petroleum ether (now about 3.6 liters) is 

 freed from methyl alcohol and acetone by washing four times with 

 2 liters of water. During this last washing the petroleum ether 

 loses its fluorescence and becomes turbid because of the precipita- 

 tion of the chloroph3dl. This Suspension is shaken with sodium 

 Sulfate and 150 gm. of talc, and then filtered through talc. The 

 filtrate still contains a little Chlorophyll and most of the Carotin. 

 The chlorophyll-containing talc is washed with ordinary petroleum 

 ether, then with low-boiling petroleum ether and finally with one 

 liter of absolute ether, which dissolves out the Chlorophyll. This 

 Solution is filtered through anhydrous sodium sulfate, conc. to 25 

 C.c, and precipitated by pouring into 0.8 liter of low-boiling petro- 

 leum ether. The yield is about 13 gm., or 6.5 gm. per kilo of leaf 

 meal. The yield is about 0.75 percent of the content of the dry leaf 

 and the Chlorophyll has a purity of about 98 percent. 



" Willstätter and Hug: Ann. d. Chem., 380, 177 {1911). 



