THE PIGMENTS OF LEAVES 529 



Hydrolysis of Phaeophytin. Preparation of Phytol, Phyto- 

 chlorin e and Phytorhodin g. 



Phaeophytin is hydrolysed with either cold or hot methyl alcoholic potash. 

 (a) i gm. is shaken for 2-3 days with quartz pebbles or glass beads and 

 10 c.c. of alcoholic potash (600 gm. in 1000 c.c. methyl alcohol) ; (b) 6 gm. of 

 phaeophytin are dissolved in 20 c.c. of pyridineat 80 and poured into a gently 

 boiling solution of methyl alcoholic potash (250 c.c. + 160 gm. KOH) con- 

 tained in a silver beaker and stirred with a silver rod and boiled gently for 

 half a minute. The beaker is cooled immediately with water. 



The cold solution is covered with ether and water is added to cause the 

 ether to separate. The alkaline solution is shaken several times with ether to 

 remove the phytol. The ethereal solution which has a brown colour is washed 

 several times with (i) dilute alkali, (2) concentrated hydrochloric acid, (3) water. 

 The acid washings have a blue-green colour. It is concentrated to 1500 c.c. 

 if 20 gm. phaeophytin are used, decolorised by shaking with charcoal and the 

 ether is evaporated off; the last traces of ether are removed by heating the 

 oily residue at 90 for f hour. The oil is purified by distillation in vacua. 



The alkaline solution (from 20 gm. phaeophytin) is diluted and acidified 

 and the pigments transferred into 1 2 litres of ether. The phytochlorin is isolated 

 by shaking the ether three times with 4 litres of 4 per cent, hydrochloric acid. 

 The acid solutions are washed with 1-1*5 litres of ether. The aqueous 

 solution is nearly neutralised and extracted with ether. The ether is evaporated 

 to about 500 c.c. ; the phytochlorin crystallises out in a yield of 5*2 gm. 



The ethereal solution containing phytorhodin is washed twice with 6 per 

 cent, hydrochloric acid to remove the last traces of phytochlorin and concen- 

 trated. It crystallises out in a yield of 2 '8 gm. 



Phytol. 



Phytol is a colourless oil which boils at 203-204 at 9-10 mm. pressure 

 and at 145 at o'o3-o'04 mm. and mixes with most organic solvents. 



As an unsaturated compound it combines with halogens and ozone and 

 is easily auto-oxidisable. On reduction it yields the hydrocarbon C 2 oH 42 and 

 on oxidation gives a ketone C 17 H 34 O. 



Phytochlorin e. 



Phytochlorin e, which is formed from chlorophyll a, consists of greenish- 

 brown crystals; it gives a brownish-black powder. It exists in two forms 

 which have slightly different solubilities in alcohol, acetic acid, acetone, chloro- 

 form. 



Phytorhodin g. 



Phytorhodin , from chlorophyll b, crystallises from ether in six-sided prisms 

 of a dark -red to black colour with metallic lustre. Its solution in ether, 

 alcohol and acetic acid is deep red in colour with a blue tinge and slight 

 dark-red fluorescence. It is easily soluble in pyridine, also in alcohol 

 and acetic acid. The crystals do not dissolve in ether and chloroform. 



