i stand corrected - happily i might add as i have 1l of C. camphora and was under the impression it wasn't worth refining - so thanks in a kinda indirect way :-)
My reference was:
https://www.thevespiary.org/rhodium/Rhodium/chemistry/safrolefaq.txt
Quote:
CAMPHOR OIL is obtained by steam distillation of the wood of the camphor
tree Cinnamonum camphora Sieb. (Lauraceae) growing in China, Taiwan, Japan
[and Australia, where it is classed as a noxious weed]. The main constituent
of the crude oil is camphor (ca. 50%) which can be separated by cooling and
centrifugation.
Fractionation of the mother liquor gives two oils:
1) White camphor oil is the first distillation fraction (ca 20% of the crude
camphor oil). It is a colourless or nearly colourless liquid with a
cineole-like odour.
2) Brown Oil of camphor is a fraction with a boiling point higher than
that of camphor (ca. 20%) It is a pale yellow to brown liquid with the
odour of sassafras oil.
Density 1.064-1.075; Optical rotation [ND20] 1.51 - 1.55
[alpha]d 0 to +3°. Flash point 6°C.
Solubility 1 vol in 2 vols of 90% ethanol.
The oil contains more than 80% safrole and, like Brazilian sassafras oil,
is therefore used as raw material for the production of piperonal via
isosafrole. Camphor oils with a high safrole content can also be obtained
by steam distillation of the wood of Cinnamonum parthenoxylon Nees.
Three Varieties of camphor oils are produced.
+---------------------------------------------------------------------------+
| Formosan Camphor oils | camphor-linalool and camphor-safrole types.
|
| Japanese Camphor oils | camphor-safrole types.
|
| Chinese Camphor oils | cineole-terpineol-camphor (Apopin Oil) type.
|
+---------------------------------------------------------------------------+
Camphor oil "true" is produced by the steam distillation of the wood,
rootstumps and branches of the type of Cinnamonum Camphora known as Hon-Sho,
which grows in Formosa and Japan. [Ed Note: Hon-Sho oil holds 18.1% safrole)
Along with the crude oil comes a solid, partly crystalline mass of crude
camphor. The oil is separated from the crude camphor by filterpressing. This
yields crude camphor oil. The crude oil is subsequently fractionally
distilled
under vacuum, and yeilds another 50% of crude camphor. The remaining 50% of
filterpressed crude camphor oil is now free of camphor. It contains light
terpenes, cineole, safrole, terpineol, sesquiterpenes, and sesquiterpene
alcohols. These are separated into various fractions known as:
+-----------------------------------------------------------------------+
| White Camphor oil | The light fraction, containing cineole and |
| | monoterpenes. |
|-------------------+---------------------------------------------------|
| Brown Camphor oil | The medium heavy fraction containing up to 80% |
| | of safrole and some terpineol. |
+-----------------------------------------------------------------------+
[Extended Monograph]
Brown oil of camphor is the medium heavy fraction from vacuum distillation
of the camphor-free oil (aka white oil, filterpressed and camphor-free).
Brown camphor oil amounts to 6 or 7 percent of the total oil, or 20-22%
of the decamphorised oil. Brown oil is produced almost entirely in
Formosa and Japan, from the Hon-Sho type of cinnamomum camphora, the
camphor tree.
This fraction is most interesting from the perfumer's point of view. Its
main constituent is safrole, and the redistilled brown camphor can be used
directly in soaps for its magnificent masking effect. The safrole can be
isolated from the oil and used as a starting material for heliotropine,
vanillin and other perfume materials. Terpineol is also separated during
the safrole-isolation and serves as is or may be transformed into terpinyl
esters.
An artificial sassafras oil, "Oil Camphor Sassafrassy" is also produced
from the brown oil by rectification and adjustment of the content of
safrole, terpenes, etc.
The extended monograph seems to be where i got things confused - on reinspection - looks like I may only get 20-22% safrole out..
Oh well still worth it.
as for the trees, hacking them down seems a little extreme to me