DESTRUCTIVE DISTILLATION OF MANILA COPAL. 211 



It is at once apparent that the carbon dioxide, oil, and water are the 

 only products given off which can play an important part in the chemical 

 changes involved dining the first stage of the decomposition. 



The products formed are similar to those obtained by the incomplete combustion 

 of hydrocarbons.- 9 



Formic and acetic acids, acetone, acetaldehyde, furfuraldehyde, ethylene, pro- 

 pylene, carbon dioxide, and methane have repeatedly been found among the 

 products of decomposition by heat of the more complex carbohydrates and other- 

 organic compounds." The formation of these substances during the distillation of 

 Manila copal can not therefore be considered as throwing much light on the 

 constitution of the original material. Their production suggests that possibly 

 a carbohydrate group may exist in some of the original resinous substance. This 

 is made somewhat more probable by the observation of Strasburger :I that, in the 

 conifers the starch content of the wood parenchyma cells is displaced by resin. 

 In other words, the resin appears to be formed at the expense of starch. The 

 same author says: "Since the conifers sacrifice considerable quantities of reserve 

 material in order to produce resin, it is clear that the starch is transported to 

 the place at which the resin formation shall take place. 



The darkening of the resin on melting is not caused by oxidation, but 

 appears to be due largely to the carbonization of some of the constituents. 

 When the distillation is performed in glass retorts, the air is quickly 

 displaced by carbon dioxide, steam, and gaseous hydrocarbons. Small, 

 black pieces of charred substance can always be seen in the clear melt. 

 Samples heated in sealed tubes to 300° darken to the same degree as 

 when heated in a retort. A sample prepared by the evaporation of a 

 clear, alcoholic solution, from which the rather insoluble flocculent matter 

 had been removed, was heated in a sealed tube. The darkening was 

 less in this case than when the original resin was employed. 



The distillation was not studied beyond the first stage except to identify 

 ethylene and propylene among the gaseous hydrocarbons. 



This was done by passing the gases through bromine water. The oil thus 

 obtained was distilled and a fraction weighing 5 grams was obtained which 

 boiled from 128° to 132°. In one experiment all of the unsaturated hydrocarbons 

 excepting ethylene were removed by passing the gas through concentrated sul- 

 phuric acid. The ethylene dibromide obtained in this case boiled between 12S° 

 and 134°. Propylene was identified in the fraction boiling from 135° to 145° 

 by heating the oil with ten times its weight of water in a sealed tube at 180° 

 for eight hours. The aqueous solution thus obtained yielded iodoform on treat- 

 ment with sodium carbonate and iodine, indicating acetone, and an oily pre- 

 cipitate separated on the addition of phenylhydrazine. which when heated with 

 zinc chloride gave off the odor of skatol, indicating propionic aldehyde. = - 



29 Stepski, Monaish. f. Ch.em. (1902), 23, 773. 



30 Fisher, E. Ber. d. deutschen chem. Ges. (1889), 22, 105; Awn. d. Chem. 

 (Liebig) (1890). 258, 230; Pinner. Ber. d. deutschen chem. Ges. (1S83), 16, 

 1730. 



- 1 Histologische Beitrage, Jena (1901), 3, 4. 



"Fisher, E. Ber. d. deutschen chem. Ges. (1889), 22, 353. 



