1914] Clarence J. West 235 



alcohol sol. is bluish green with a deep red fluorescence, It is in- 

 soluble in 80 percent methyl alcohol and in petroleum ether. The 

 ethereal sol., shaken with 6 percent hydrochloric acid, is slowly de- 

 composed, while 20 percent acid decomposes it immediately. 



Chlorophyll b gives a dark red phase with alkali, and as a decom- 

 position product only phytorhodine g. It is dark green to bltiish 

 black in color; usually forms crystals that may easily be filtered 

 off; and, in general, is less soluble than the a component, being 

 entirely insoluble in cold petroleum ether. The alcoholic sol. has 

 a yellowish tinge when compared with that of a. It fluoresces 

 brownish red. A colloidal Solution is yellow green with a dark 

 olive green opalescence. It is somewhat less easily decomposed by 

 shaking with acids. 



There seems to be a fairly definite relation between the two 

 components, one molecule of Chlorophyll b being accompanied by 

 three molecules of Chlorophyll a. (In the same way a similar rela- 

 tion is found between the yellow pigments, one molecule of Carotin 

 being accompanied by about one and a half molecules of xantho- 

 phyll. The relation between the Chlorophyll (a-\-b) and the yel- 

 low pigments is about one molecule to 0.35 molecule.) 



The analyses of the two components, dried in a high vacuum, 

 interpreted in the light of analyses of decomposition products of 

 these substances, lead to the f ollowing f ormulas : 



Chlorophyll a: C55H7205N4Mg -[- 0.5 mol. of HoO (half hydrate). 

 Chlorophyll b : CssH^oOgN^Mg. 



Several of the Compounds studied give analytical figures for 5.5 or 

 6.5 atoms of O. Since molecular weight estimations indicate that 

 the molecule is not to be doubled, these Compounds are to be con- 

 sidered as half hydrates. 



Allomerization.^^ It was mentioned above that allomerization 

 was one of the difficulties met with in the earlier methods of extrac- 

 tion. This name is given to a certain change, perhaps isomeric in 

 nature, which Chlorophyll and some of its decomposition products 

 undergo when allowed to stand in alcohol or petroleum ether sol. 

 for some time. The allomerized product has lost its property of 



^5 Willstätter and Utzinger : Ann. d. Chem., 382, 129 (1911) ; Willstätter and 

 Stoll: Ibid., 387, Z'^^J (iQn)- 



