230 PIGMENTS 



The Action of Alkalies. 



When the two chlorophylls are treated with the calculated 

 amount of concentrated methyl alcoholic potash their ester 

 groups are hydrolysed, and two isomeric tribasic acids result 

 from each which are known as chlorophyllin and isochloro- 

 phyllin a or b, as the case may be : 



/COOCH 3 /COOH 



C 31 H 29 N 3 Mg . 



NH NH 



Chlorophyll a Chlorophyllin a and 



Isochlorophyllin a 



/COOCH 3 xCOOH 



Chlorophyll b Chlorophyllin b and 



Isochlorophyllin b 



Chlorophyllin a when heated with alkali loses carbon- 

 dioxide, and yields two isomeric dibasic acids, glaucophyl- 

 lin and rhodophyllin, C 31 H 32 N 4 Mg(COOH) 2 , and at a higher 

 temperature it loses two molecules of carbon dioxide, yielding 

 a monocarboxylic acid, pyrrophyllin, C 31 H 33 N 4 Mg(COOH). 

 By heating with soda lime the third molecule of carbon 

 dioxide may be removed with the formation of aetiophyllin a 

 substance containing no carboxyl group at all, and to which 

 the following formula is assigned : 



CH = CH 



I I 



O 



i 



c 2 H.c--a I en 



C 2 H 5 - C = C \ / c = C-C 2 H 5 



C C == 



CH 3 CH 3 



Aetiophyllin 



