[656] L. V. Udrànsky and Baumann, Ber., xxi. 2744.
The process is specially applicable for the separation of ethylenediamine, pentamethylenediamine (cadaverine), and tetramethylenediamine (putrescine) from urine. In a case of cystinuria Udrànsky and E. Baumann[657] have found 0·24 grm. of benzoyltetramethylenediamine, 0·42 grm. of benzoylpentamethylenediamine in a day. Diamines are absent in normal fæces and urine. Stadthagen and Brieger[658] have also found, in a case of cystinuria diamines, chiefly pentamethylenediamine.
[657] L. V. Udrànsky and Baumann, Zeit. f. physiol. Chem., xiii. 562.
[658] Arch. pathol. Anatom., cxv. p. 3.
The operation is performed by making the liquid alkaline with soda, so that the alkalinity is equal to about 10 per cent., adding benzoyl chloride, shaking until the odour of benzoyl chloride disappears, and then filtering; to the filtrate more benzoyl chloride is added, the liquid shaken, and, if a precipitate appears, this is also filtered off, and the process repeated until all diamines are separated.
The precipitate thus obtained is dissolved in alcohol, and the alcoholic solution poured into a considerable volume of water and allowed to stand over night; the dibenzoyl compound is then usually found to be in a crystalline condition. The compound is crystallised once or twice from alcohol or ether, and its melting-point and properties studied. Mixtures of diamines may be separated by their different solubilities in ether and alcohol.