“AnatyBeal Notes. 
The estimation of the alcohol content of essential oils by ihe acetylation 1 
effected, as is generally known, by means _ the formula: — Sn tan 
MD Gi 
20><(s— a>< 0.021)’ 
m = molecular weight of the alcohol calculated, 
= amount of c.c. seminormal caustic potash solution, 
S$ = weight in grams of acetylated oil used. 
In Gildemeister’s text-book The Volatile Oils (1910), 2n4 edition, vol. I, p. 576, it tiered 
been stated, when discussing the above formula, that a possible content. of primarily 
esterified alcohols in the oil is herein not taken into account. Consequently, the 
values calculated are generally found to be too high. In such cases, when the_ ester 
content of the oil is low, the error is but insignificant and for practical purposes. need 
not be taken into consideration. The difference, however, incréases in proportion to. | 
the ester content and must then be eliminated. To this end, we suggested the following 2 
modus procedendi: — From the difference of the ester values of the original and the | 
acetylated oil, the amount of free alcohols in the oil is calculated, then amount of 
combined alcohols, such as found by the ester value of the original oil, is added 
thereto, thus giving the amount of total. alcohols in the oil. x 
The results obtained by this method are likewise not quite correct, since the ester! a 
value is calculated the first time from the original oil, for the second time from the 
acetylated oil. ‘This discrepancy is taken into account by a new formula worked out 
recently by T. Tusting Cocking'), which therefore gives quite exact results. The formula | 
runs as follows: —_ | i. 
per cent. alcohol in ae ol — 
in which 
g 
m><(E.V. Il —E.V.) 
re. 0.42<(1333 — E.V. II) 
in which m = molecular weight of alcohol calculated”), Si 
E.V.1 = ester value of the original oil, ae a 
E.V.II = ester value of the acetylated oil. ? eS 
per cent. of alcohols in original oil — 
This formula is based on the following consideration. 
One g. of oil gains x g. by acetylation, owing to addition of CH;COOH ‘and loss 
of H,O. The increase is CHsCO with the molecular weight 42 corresponding to 56 g. 
KOH, so that 1 g. CH,CO equals 1.333 g. KOH, in other words, the ester value of — 
CHCO is 1333. | ae a 
Now, 1 g. original oil require . . . E.V.I mg. KOH e 
1 g. acetylated oil require . . E.V.II mg. KOH i 
1 g. C,H,O ee we ee SSS aI 
Hence, 1 g. original oil + x g..C.H,O require (E.V.1 +- 1333 x) mg. KOH 
Furthermore, 1 g. original oil + x A ee correspond to (1-++ x) g. acetylated oil, , 
and since (1-+-x) g. acetylated oil require (1-++x) < E.V.I] mg. KOH, rte Tesults 
EV 14-1333 = 40-3) ve, 
from which follows: — E.V. lI — E.V.I LAN aie 
) Xx. SS ee pe, pre 
‘ [333 EN Chg | ier 
1) Perfum. Record 9 (1918), 37. — 7) In the original paper, the atomic weights are calcu : 
basis of O = 16. in correspondance to the formulz employe elsewhere in Gildemeister’s text-bo 2, 
