N. O. GEAMINE^] 69
It is of a considerably higher value than the ordinary Ceylon oil, and has
a quite different and much finer odour. The principal difference between
it and the Ceylon oil lies in its considerably higher citronellal value, and,
naturally, a much higher content of total acetylisable constituents.
De Jong has carried out a series of experiments on the oil value of
Java citronella grass in various stages of development in order to decide
which is the most favourable time for distilling. As the leaf ages the
oil content decreases; the sheaths of the leaves and the roots contain
much less oil than the leaves themselves. De Jong considers it the best
plan to cut the grass as soon as four or five leaves have developed. As
regards' the properties of oil from different batches of old leaves, the
optical rotation and total geraniol content (geraniol and citronella) show
only insignificant variations. The rotation varies irregularly ; values
ranging from - 2° 7' to - 7° 36' being observed in oil from leaves of
various ages. The total geraniol content first increases in an ascending
scale from the newest up to the oldest leaf and afterwards decreases in
a corresponding manner ; the lowest value was 85'5 per cent., the highest
93*3 per cent. The results of this investigation induced de Jong to make
experiments as to the time required for acetylation, the behaviour of the
oil towards acetic anhydride, the amount of acetate of sodium to be added,
and the time required for saponification. As a result of these inquiries
de Jong considers that two hours are needed both for acetylation and for
saponification, and that for every 20 c.c. of oil and acetic anhydride,
2 grms. of sodium acetate are required in order to yield accurate re-
sults. He draws these conclusions because in his experiments on citron-
ella oils he obtained the highest values by using these precautions.
The oils examined by de Jong were soluble in three parts of 80 per
•cent, alcohol; when more than four parts of the solvent were used,
turbidity ensued.
Ultee has carried out a series of experiments on the oil distilled from
plants grown at Salatiga, which is south-east of Buitenzorg where de
Jong's oils were distilled. The former place is situated at a considerably
higher altitude than the latter. Ultee obtained 0'66 per cent, of oil hav-
ing the following characters :—
d29o 0-8721, AD - 3° 15', total geraniol 92'75 per cent., soluble in
1 5 volume and more of 80 per cent, alcohol. The oil was distinguish-
able from the Buitenzorg distillates in the first place by its greater
solubility, for according to de Jong the Buitenzorg oils only gave a clear
solution with 3 volumes of 80 per cent, alcohol, which became cloudy
when diluted to over 4 volumes. As Ultee only obtained an oil yield of
0'66 per cent., whereas in Buitenzorg the yield ranged from 05 to 0 9
per cent., experiments were made at Salatiga to ascertain whether the
oil content of the grass could be raised by suitable fertilising. Out of
four experimental fields, three were treated for this purpose with dif-
ferently composed artificial manures. The grass was cut after ten
weeks and equal quantities of it distilled in an exactly similar manner.
The oil yields obtained ranged from 060 to 0'65 per cent., showing that
manuring had not affected the oil content of the grass.
Java citronella oil has the following characters :—
Specific gravity. 0-882 to 0-898
Optical rotation
Refractive index
Total acetylisable constituents
Geraniol.
Citronellal
- 2° to - 3° (rarely + 2° to - 5°)
1-4640 to 1-4725
80 to 94 per cent.
35 „ 45 „
35 „ 50 ,,