CHLOROPHYLL 



231 



The Action of Acids. 



Acids, especially oxalic acid, remove magnesium from all 

 derivatives containing this element, replacing it by two atoms 

 of hydrogen without altering the rest of the molecule. 



Thus chlorophyll a and b give by removal of Mg the com- 

 pounds 



/COOCHo 

 tj r\xr / 



Phaeophytin a 



Phaeophytin b C 32 H 30 O 2 N 4 



and 



^/COOCHa 

 XCOOC^H^ 



respectively, while chlorophyllin a gives phytochlorin f and 

 -, C 32 H 32 ON 4 (COOH) 2 . On the other hand, glauco and 

 rhodophyllin by removal of magnesium give glauco and 

 rhodoporphyrin C 31 H 34 N 4 (COOH) 2 , while pyrrophyllin yields 

 pyrroporphyrin C 31 H 35 N 4 (COOH). By removing the last car- 

 boxyl from the latter compound a substance aetioporphyrin 

 C 31 H 36 N 4 is obtained, which is the magnesium free analogue 

 of aetiophyllin C 31 H 34 N 4 Mg. 



CRYSTALLINE AND AMORPHOUS CHLOROPHYLL. 



The physical constants of these substances as determined 

 by Willstatter and his pupils are as follows : 



Chlorophyll (a and b). 

 Analysis agrees with for- 

 mula C^H^O^Mg. 

 Bluish-black glistening. 



powder, with metallic 



lustre. 

 Appears crystalline under 



the microscope. 

 No definite M.P. 



Practically insoluble in 

 cold light petroleum, 

 but dissolves readily on 

 addition of a few drops 

 of methyl or ethyl alco- 

 hol. 



Chlorophyll a. 

 C 55 H 72 5 N 4 Mg. 



Bluish-black powder. 



Bluish-black powder. 



Sinters and forms a vis- 

 cous mass at 117-121 



Very sparingly soluble in 

 light petroleum, but 

 dissolves verv easily in 

 most organic solvents. 



Chlorophyll b. 

 C 55 H 70 6 N 4 Mg. 



Dark green or greenish- 

 black glistening powder. 



Dark green or greenish- 

 black glistening powder. 



Sinters at 86-92, and be- 

 comes viscous at 120 

 130. 



Quite insoluble in light 

 petroleum, and is gener- 

 ally somewhat less 

 soluble than chloro- 

 phyll a. 



