Dr. J. Schorm, of Vienna, the author of this paper, after remarking
that in spite of the increase of the consumption of coniine, the
methods hitherto in vogue for preparing it yielded an article which
darkened on exposure to the air, and the salts of which crystallized
but badly, gives the following method for preparing pure coniine and
its salts:
_PREPARATION OF CRUDE CONIINE._
A.--100 kilogrammes of hemlock seed are moistened with hot water, and
after swelling up are treated with 4 kilogrammes of sodium carbonate
previously dissolved in the requisite quantity of water (caustic
alkalies cannot be used). The swollen seed is worked up uniformly with
shovels, and then placed in an apparatus of 400 kilogrammes capacity,
similar to that used in the distillation of ethereal oils, and charged
with steam under a pressure of three atmospheres. Coniine distills
over with the steam, the greater part separating out in the receiver
as an oily stratum, while a part remains dissolved in the water. The
riper the seeds, the greater is the percentage yield of oily coniine,
and the sooner is the distillation ended. The distillate is
neutralized with hydrochloric acid, and the whole evaporated to a weak
sirupy consistence. When cool, this sirup yields successive crops of
sal-ammoniac crystals, which latter are removed by shaking up the mass
with twice its volume of strong alcohol, and filtering. This filtrate
is freed from alcohol by evaporation over a water bath, the
approximate quantity of a solution of caustic soda then added, and the
whole shaken up with ether. The ethereal solution is then cooled down
to a low temperature, whereby it is separated from conhydrine, which,
being somewhat difficultly soluble in ether, crystallizes out.
B.--The bruised hemlock seed is treated in a vacuum extractor with
water acidulated with acetic acid, and the extract evaporated in vacuo
to a sirupy consistence. The sirup is treated with magnesia, and the
coniine dissolved out by shaking up with ether.
The B method yields a less percentage of coniine than A, but of a
better quality.
_RECTIFICATION OF THE CRUDE CONIINE._
The solution of crude coniine in ether obtained by either of the above
processes is evaporated over a water bath to remove the ether, mixed
with dry potassium carbonate, and then submitted to fractional
distillation from an air bath. The portion distilling over at 168° C.
to 169° C. is pure coniine, and represents 60 per cent. of the crude
coniine.
Coniine thus prepared is a colorless oily liquid, volatile at the
ordinary temperature, and has a specific gravity of 0.886. At a
temperature of 25°C it absorbs water, which it gives up again upon
heating. It is soluble in 90 parts of water. It is not altered by
light.
The author has formed a number of salts from coniine thus prepared,
and finds them all crystallizable and unaffected by light.--_Berichte
der deutschen chemischen Gesellschaft._--_Chem. and Druggist._
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