402 



condenser. The oil was afterwards separated, and the alkaline portion distilled ; 

 nothing came over below 100 C., so that alcohols boiling below that temperature 

 were absent. The precipitate which had formed was filtered off and ignited; it 

 was found to consist almost entirely of ferric oxide, which had evidently been 

 derived from the iron digesters; and this acting on the phenols gave the deep 

 red colour to the crude oil. The filtered solution, when evaporated to a small 

 bulk, separated a dark substance which became semi-solid on cooling. On 

 acidifying this with sulphuric acid, an acid was obtained which, on purification, 

 gave crystals differing in no respect from eudesmic acid, previously obtained 

 from the oil of E. aggregata. Amyl-eudesmate thus occurs in the oil of this 

 species, and is probably a frequent constituent in Eucalyptus oils. The aqueous 

 filtrate from the solid acid separated as above, was acidified with sulphuric acid, 

 and repeatedly distilled until the whole of the volatile acids had been obtained. 

 The distillate which had a strong odour of valeric acid, was neutralised with soda, 

 and evaporated to dryness ; the crystalline salt thus obtained, was decomposed 

 with sulphuric acid, when an oily acid separated, having the objectionable odour 

 of iso-valeric acid. The separated acids were recovered by agitating with ether 

 and the ether removed. The product had the odour of, and gave the reaction 

 for valeric acid, agreeing in this respect with those obtained with a sample of 

 pure iso-valeric acid. The molecular value of the acid or acids thus obtained 

 was determined in the ordinary way from the barium salt ; 0-3328 gram, of the 

 barium salt gave 0-2327 gram, of barium sulphate when ignited with sulphuric 

 acid, equal to 69-92 per cent. BaSO 4 or 41-08 per cent, of barium. Ba2C 5 H 9 O 2 

 contains 40-45 per cent, of barium, and gives 68-73 per cent, of barium sulphate. 

 It is thus apparent that the volatile acids occurring as an ester in some 

 Eucalyptus oils, and particularly in the oil of E. saligna var, pallidavalvis is 

 principally valeric acid, and most probably the iso-form. 



The oil recovered after saponification with aqueous potash was then 

 distilled, in order to determine, if possible, what alcohols were present. It was 

 certain that one of these was amyl alcohol, derived from the ester of eudesmic 

 acid, and on acetylating the portion distilling between 130 C. and 150 C. amyl 

 acetate was readily obtained. Below 130 C. only a few drops came over ; but 

 between 130 C. and 150 C. 7 per cent, distilled, while between 155 C. and 

 160 C. 66 per cent, distilled ; this fraction was almost entirely dextropinene, and 

 had specific gravity 0-868 at 15 C. The specific gravity of the fraction 130 C. 

 and 150 C. was 0-850 at 15 C. What the alcohol is, if any, in the oil of 

 this species besides amyl, we have not so far been able to determine, and 

 further research is necessary to decide this question. Until this point is settled 

 it would be difficult to calculate the actual percentage of ester in many Eucalyptus 

 oils, particularly in cases when both the acetic acid ester and the valeric acid 

 ester occur together. When the saponified oil was acetylated the saponification 

 number was found to be 54-04, which, calculated as CH 3 COOC 5 H J: gives 12-55 

 per cent. The acetylated oil had a marked odour of amyl-acetate which was 

 not masked by the terpenes present. That some free alcohol was also present 

 in the oil of this species was shown by the saponification number of the original 

 crude oil, including that of the free acid, being only 41-76. 



It is, perhaps, worthy of remark that Eucalyptus oils which contain the 

 valeric acid ester also show the presence of the corresponding aldehyde, and that 

 crude cineol-pinene oils which have the most objectionable odour of volatile 

 aldehydes, usually contain the valeric acid ester. From the results of these 

 investigations it appears that the valeric acid in Eucalyptus oils occurs mostly 

 as an ester and not in the free condition, because the free acid in Eucalyptus oils 

 is acetic. (See the article dealing with the free volatile acid of Eucalyptus oils.) 



