III. Contributions towards the history of the ethylene bases

Abstract

The manufacture of chloral, which, since the discovery of the remarkable physiological properties of this compound, is conducted on a daily increasing scale, gives rise to a variety of secondary products which have not failed to attract the attention of chemists. Some time ago I showed that the most volatile fraction of these by-products consists almost entirely of chloride of ethyl, constituting a very valuable material for the preparation of an abundant quantity of the ethylated ammonias. The fraction boiling between 70° and 100° is chiefly bichloride of ethylene, which, when submitted to the action of alcoholic ammonia at 100°, furnishes a supply of ethylene bases such as would be difficult to obtain from other sources. Dr. Schering, one of the principal manufacturers of chloral in Berlin, has lately placed at my disposal between 30 and 40 kilograms of these latter by-products, which the kindness of my friends Drs. Martius and Mendelssohn, by placing at my disposal one of their magnificent enamelled autoclaves, has permitted me to treat in one single operation with alcoholic ammonia. The product of this operation was a large proportion of sal-ammoniac deposited in crystals, and a dark alcoholic mother-liquor which, after the alcohol had been distilled off, yielded on evaporation a brown crystalline residue, consisting of salts of ethylene bases. Large quantities of ethylenediamine chlorhydrate in a state of absolute purity were separated from this mixture by systematic crystallization. An additional portion was procured by distilling the mother-liquor, after it had ceased to crystallize, with an alkali, collecting apart the products, as long as they yielded with chlorhydric acid the easily crystallizable ethylenediamine salt. In this manner more than a kilogram of the perfectly pure chlorhydrate was obtained, not to speak of quantities of the more complex bases, which I have not yet endeavoured to separate.