Cocaine is manufactured from the dry leaves of the _Erythroxylon
coca_, which grows in the valleys of the East Cordilleras of South
America--i.e., in the interior of Peru and Bolivia. The fresh leaves
contain 0.003 to 0.006 per cent of cocaine, which percentage decreases
considerably if the leaves are stored any length of time before being
worked up. On the other hand, the alkaloid can be transported and kept
without decomposition. This circumstance caused the author to devise a
simple process for the manufacture of crude cocaine on the spot,
neither Peru nor Bolivia being suitable countries for complicated
chemical operations. After many experiments, he hit upon the following
plan: The disintegrated coca leaves are digested at 70° C. in closed
vessels for two hours, with a very weak solution of sodium hydrate and
petroleum (boiling between 200° and 250° C). The mass is filtered,
pressed while still tepid, and the filtrate allowed to stand until the
oil has completely separated from the aqueous solution. The oil is
drawn off and carefully neutralized with very weak hydrochloric acid.
A white bulky precipitate of cocaine hydrochloride is obtained,
together with an aqueous solution of the same compound, while the
petroleum is free from the alkaloid and may be used for the extraction
of a fresh batch of leaves. The precipitate is dried, and by
concentrating the aqueous solution a further quantity of the
hydrochloride is obtained. Both can be shipped without risk of
decomposition. The product is not quite pure, but contains some
hygrine, traces of gum and other matters. Its percentage of alkaloid
is 75 per cent., while chemically pure cocaine hydrochloride
(C_{17}H_{21}NO_{4}.2HCl) contains 80.6 per cent. of the alkaloid. The
sodium hydrate solution cannot be replaced by milk of lime, nor can
any other acid be used for neutralization. Alcohol or ether are not
suitable for extraction. A repetition of the process with
once-extracted coca leaves gave no further quantity of cocaine,
proving that all the cocaine goes into solution by one treatment. The
same process serves on the small scale for the valuation of coca
leaves. 100 grms. of coca leaves are digested in a flask with 400 c.c.
of water, 50 c.c. of 1/10 NaOH (10 grms. of NaOH in 100 c.c.) and 250
c.c. of petroleum. The flask is loosely covered and warmed on the
water bath for two hours, shaking it from to time. The mass is then
filtered, the residue pressed, and the filtrate allowed to separate in
two layers. The oil layer is run into a bottle and titrated back with
1/100 HCl (1 grm. of HCl in 100 c.c.) until exactly neutral. The
number of c.c. of hydrochloric acid required for titrating back
multiplied by 0.42 gives the percentage of cocaine in the sample. The
following are some of the results with different samples of coca
leaves of various age:
Contained per cent.
of Cocaine.
Coca leaves from Mapiri, 1 month old 0.5% \
" " " Yungas " " 0.5% |
" " " Mapiri and Yungas |
6 months old 0.4% | Of the
" " " Cuzco (Peru) |_ weight of
6 months old 0.3% | the dry
" " " Mapiri and Yungas | leaves.
1 year old 0.3% |
" " " Cuzco " " " 0.2% |
" " " Mapiri and Yungas |
2 years old 0.15%/
Coca leaves from Yungas and Cuzco, three years old, contained no trace
of the alkaloid, whereas fresh green leaves from Yungas contained 0.7
per cent. of the weight of the dry leaves. The same process is also
applicable for the manufacture of quinine from poor quinine bark, with
the single alteration that weak sulphuric acid must be used for the
neutralization of the alkaline petroleum extract.--_H.T. Pfeiffer,
Chem. Zeit. 11._
* * * * *
[Continued from SUPPLEMENT, No. 622, page 9941.]