— 120 



method, owing to the partial decomposition which occurs during the 

 process, V. Boulez 1 ) recommends a method which apparently gives 

 good results. Boulez endeavours to prevent the decomposition of 

 the alcohols by diluting them with an indifferent substance (for 

 example, oil of turpentine), and acetylating the mixture. In the case 

 of linalool he proceeds as follows: 5 g. linalool are diluted with 25 g. 

 oil of turpentine, whose acetylation number must be previously ascert- 

 ained, then 40 g. acetic anhydride and about 3 to 4 g. sodium acetate 

 are added, and the whole boiled for three hours. After washing 

 and drying, he saponifies about 1 g. of the acetylated mixture with 

 25 cc. alcoholic x / 4 n. potash liquor, and in this manner ascertains the 

 acetylation number. From this Boulez calculates, with due regard 

 to the acetylation number of the turpentine oil, the linalool-content 

 of the mixture; but he here commits the error that in his calculation 

 he identifies the percentage composition of the original oil with that of 

 the acetylated oil, and calculates the ester numbers of the acetylated 

 substance straightway as those of the original oil, which is naturally 

 bound to give incorrect results. Boulez namely calculates as follows: 

 If 100 g. of the original oil mixture contain 83,3 g. turpentine oil 

 of the ascertained acetylation number 10,5, the portion of the total 

 alkali quantity belonging to the turpentine oil, which has been ascert- 

 ained by the saponification of the acetylated oil mixture, amounts 



to 0,874 g., corresponding to the formula — — , and this figure 



is deducted from the total alkali quantity referred to, in order to find 

 the alkali quantity corresponding to the 16,7 g. acetylated linalool. 



The error in this calculation is at once apparent, if it is considered 

 that the proportionate figures 16,7 g. linalool: 83,3 g. turpentine oil relate 

 to the original not yet acetylated oil mixture, and that this ratio after 

 the acetylation is of course completely changed by the entry of an 

 acetyl-group in the alcoholic body, and that in such manner, that if 

 1 g. original oil mixture consisted of 0,167 g- linalool and 0,833 g- 

 solvent, 1 g. of the same oil mixture after the acetylation consists 

 of 0,203 g- hnalyl acetate and 0,797 g. solvent. 



Now, for the correct calculation the following considerations should 



apply: if x grams of the acetylated oil mixture require a cc. normal 



potash liquor for saponification, the corresponding quantity of alcohol 



#X i5j4 



calculated for 100 g. original oil amounts to ; r. The 



G b ^-(0X0,042) 



number 15,4 is V10 th °f tne molecular weight of the alcohol in 



question (linalool = 154), and the number 0,042 represents the acetic 



acid equivalent corresponding to 1 cc. normal liquor, by which an 



x ) Les corps gras 33 (1907), 178; Bull. Soc. Chim. IV. 1 (1907), 117. 





