218 



combined aldehyde was liberated by caustic soda solution and 

 extracted witli benzene. This separation was performed on 

 aldehyde C obtained from the residual oil by Experiment e. 

 The aldehyde which combined with the neutral sodium sul- 

 phite, after separation by the above process and evaporation 

 of the benzene, was distilled under reduced pressure. The 

 bulk distilled at 121° C. at a pressure of 25 mm. and was 

 quite colourless. The following constants were obtained: — 

 Specific gravity at 18° C. =0-9442; corrected for 15°C.= 

 0-9462; rotation, =-65-61°; refractive index at 20°C.= 

 1-4834; dispersion, 0-01247. 



The aldehyde which did not combine with neutral sodium 

 sulphite, and which was extracted with benzene, was 

 separated from the latter and distilled under reduced pressure. 

 It did not distil at so constant a temperature as the sample 

 above. The temperature rose from 125 to 135° C. during the 

 distillation, while the pressure decreased from 28-5 to 

 20*5 mm. This aldehyde had a rotation of —70-64°, and 

 was not oxidised by exposure in the atmosphere, the rotation 

 remaining unaltered after exposure in an open beaker for 

 fourteen days. This point is here stressed, as H. G. Smith, (2) 

 in his separation of these aldehydes from Eucalyptus oils, 

 states that this fourth aldehyde is oxidised by the air and 

 closely resembles the phellandral separated by Schimmel and 

 Co'. from water fennel oil. (The volatile oils, by Gildemeister 

 and Hoffman, page 432.) The aldehyde here separated can- 

 not be phellandral, as the latter is oxidised on exposure to 

 the air. This separation was also performed on aldehyde C 

 of Experiment g. The aldehyde which combined with the 

 sodium sulphite after separation was distilled under reduced 

 pressure; about two- thirds of it distilled at 126° C, the 

 pressure being constant at 32 mm. ; the temperature then 

 gradually rose to 130° C. The distillate gave constants prac- 

 tically identical with those from Experiment e (see above). 



These constants are practically the same as those obtained 

 in the first separation and agree with those given by H. G. 

 Smith for Cryptal.(3) No crystalline oxime could be separated 

 from this aldehyde. 



The aldehyde which did not combine with sodium sul- 

 phite was distilled under reduced pressure and collected in 

 two fractions : — 



(a) 121°-126° C. 21 mm. 33 ccs. 

 (b) 1 36°-140°C. 32 mm. 26 ccs. 



(2) "A Research on the Eucalypts and their Essential Oils," by 

 R. T. Baker and H. G. Smith, p. 286. 

 (i)Ihid, p. 387. 



