234 Willstäfter's Researches on Chlorophyll [Jan. 



tion of a little methyl or ethyl alcohol. It shows neither acid nor 

 basic properties. By the action of acids the color is changed into 

 olive brovvn, the magnesium being split off. Picric acid does not 

 give a picrate biit decomposes the Chlorophyll, givinj a brown 

 Solution. 



Chlorophyll a and b. Chlorophyll, as ordinarily obtained, is 

 a mixture of two components, designated as a and b. This fact 

 was first noticed by Stokes,^^ who used alcohol and carbon disulfide 

 to " disentangle the two." The method now used depends uponthe 

 partition of the Chlorophyll mixture between methyl alcohol and 

 petroleum ether; component a goes into the petroleum ether, com- 

 ponent h into the methyl alcohol phase. The method is carried out 

 as follows:^'* Eight grams of Chlorophyll are dissolved in 150-200 

 c.c. of ether, filtered and poured into 4 liters of petroleum ether, 50 

 or 100 c.c. of methyl alcohol being added if necessary to clear the 

 Solution. This liquid is then extracted fourteen times with 2 liters 

 of 85 percent methyl alcohol, previously saturated with petroleum 

 ether and containing o.oi gm. of oxalic acid per liter. This re- 

 moves practically all of component h. The methyl-alcohol extracts 

 are brought to a concentration of 90 percent, washed with i liter of 

 petroleum ether, poured into 2 liters of ether and mixed with a 

 large quantity of water. The ether-petroleum ether sol. is then 

 freed from methyl alcohol by washing with water, conc. to 500 c.c. 

 and then in vacuum to 30-40 c.c, and Chlorophyll h precipitated 

 with 300 c.c. of petroleum ether (boiling between 30° and 50° C.) 

 and the precipitation repeated twice, when it is free from component 

 a. The petroleum ether sol. of a is washed with water until all the 

 Chlorophyll is precipitated, the Suspension filtered, the Chlorophyll 

 taken up in ether and the ether removed in vacuum. The yield of 

 a is about 3.5 to 4 gm., of b, about 1.5 gm., together with 2 or 3 gm. 

 of a mixed Chlorophyll. 



Properties of Chlorophyll a and b. Chlorophyll a is char- 

 acterized by giving a pure yellow phase with methyl alcoholic 

 potash sol. and only phytochlorine ^ as a decomposition product. 

 It crystallizes in thin lancet-like leaflets forming a bluish black 

 powder with steel blue luster. It melts at Ii7°-i20° C. The ethyl 



i^Stokes: Proc. Royal Soc, 13, 144 (1864). 



1* Willstätter and Isler: Ann. d. Chem., 390, 269 (1912). 



