![Thumbnail: [Volume 8, 1875 page 338]](/journals/rsnz/images/rsnz_08/thumbnails/rsnz_08_00_0382_0338_ac_02.gif)
Art. XLV.—On the Solubility of the Alkalies in Ether.
[Read before the Wellington Philosophical Society, 29th January, 1876.]
It has hitherto been supposed by chemists that the alkalies are insoluble in ether, but, having been led to doubt the truth of this supposition, from observing certain facts which lately came under my notice, I at once set to work to investigate the matter, and, as it is one of some importance in connection with toxicological examinations, I think it proper to submit the results to you.
My experiments for this purpose were performed both with hydrous and anhydrous ether.
Taking first the hydrous ether, that is the commercial article and that which we really have to deal with in the kind of examinations above alluded to, I agitated separate portions of it with an aqueous solution of caustic potash and carbonate of soda (common soda), then decanted the ether off into clean test tubes, and again from these tubes into platina vessels. I then allowed the liquids to evaporate, when I found the residues resulting from this had a very alkaline reaction, and which was persistent when they were gently ignited, and dissolved in water, clearly showing that a fixed alkali was present in both cases in a free state, or at least as a carbonate. Both magnesia and lime also dissolve in this kind of ether to a notable extent. Bi-carbonate of soda, however, hardly appears to do, or, if so, only in minute quantities.
In regard now to the solvent power of ether itself, that is the anhydrous substance, I find that, when this is mixed with dry potassic hydrate, allowed to clear and then decanted off, a marked alkaline reaction is also
![Thumbnail: [Volume 8, 1875 page 339]](/journals/rsnz/images/rsnz_08/thumbnails/rsnz_08_00_0383_0339_ac_02.gif)
obtained by dipping reddened litmus paper into it, and which is more intense than can be occasioned by any minute trace of alkaline acetate possibly present in the ether, resulting from an inter-reaction of the potash upon it.
The alkalies and their inferior carbonates, therefore, not being insoluble in ether, and alkaloidal carbonates being, as I find, freely soluble therein, I would recommend in special cases, for isolating and obtaining pure alkaloids by Stras's process the use of bi-carbonate of soda, or, better still, an earthy carbonate, in place of caustic alkali, as now employed in aid of this.
I may perhaps be permitted to state further in reference to the solvent property of anhydrous ether, that I find many salts are soluble to a notable extent in it, which are insoluble or nearly so in that which is hydrous; for instance, the chlorides of calcium, nickel, zinc, cadmium, and platinum, also the sulpho-cyanides of nickel, copper, and zinc. The addition of a small quantity of water to any of these etherial solutions generally renders them very turbid, as the salt they contain is thereby precipitated as a hydrate. By the use of anhydrous ether, and by conducting the necessary evaporations in dried air, it is in fact possible to form many saline compounds hardly, if at all, producible otherwise. In this way I have prepared double sulpho-cyanides of nickel and even of copper with certain alkaloids, using chloride of calcium to dehydrate the saline solutions requisite for this.