THE PAPER CHROMATOGRAPHIC SEPARATION OF COBALT(I1) CHLORIDE AND SOME AMMINE AND ETHYLENEDIAMINE COMPLEXES OF COBALT(II1) INTROIZ'UCTION
In the paper-chromatographic separation of metal-ammine compleses, the metal can either be converted to the comples by using an ammoniacal solvent system, or it can be applied to the paper as a prepared complex ERDE~~ AND ERLENMIWER~ have studied the behaviour of cadmium acetate in ammoniacal solvents, and interpret the triple spotting of cadmium as indicating the separation of different ammine compleses. A few separations of trivalent cobalt complexes have been described. YAMA>IOTO et al.2 and LEDERER~ have investigated some ammine compleses ; STEFANOVI~ AND J.~xJI~~ have separated the geometric isomers of three ethylenediamine compleses. Since the work described here was completed, SINGI-I ANI> Dr&j have obtained separations of the ammines of copper, silver, cadmium, nickel and cobalt, using 50% ethanol as eluting solvent. Further, AGRINIBR~, in a study of the application of paper chromatography to the determination of certain elements in minerals, has separated silver, lead, selenium, zinc and copper by elution with concentrated ammonia.
It has now been found possible to separate copper, cobalt and nickel, and zinc from cadmium using a selected ternary solvent system of methanol-water-ammonia, which does not give double-spotting with cadmium. The behaviour of 14 ammine and ethylenddiarnine compleses in: acetone-aqueous hyclrochloric acid, methanolaqueous hydrochloric acid, and ether-methanol-aqueous hydrochloric acid has been investigated in some detail, and a number of new separations are described. Brief mention of some of this work has been made elsewhere'. Preparation of the solzctions BSPERI&IENTAL 0.1 N solutions of copper, cobalt, nickel, zinc and cadmium acetates were used for spotting the chromstograms described in Section A. The compleses Co(en),Cl, *, Wen) &l,l Cl, and [Co(en) 2W20)21 chi were prepared as follows: *en = ethylenediantine. References p. 379, F. I-1. POLLARD Cl cd. VOL. 2 (1959) follotied by treatment with ammonium chloride (z g), the comples being precipitated by the gradual addition of methylated spirit ( IOO ml). e 18 I?. I-I. POLLARD AND A. J. R,\NIsrER, Awd. Chiw. Ada, 14 (1956) 70.