17831. Focusing ion exchange as a method of separation of metal-ions, taking place in homogeneous solution in the presence of a complex-formation-and an electrical potential-gradient, is again confronted with heterogeneous ionexchange and ionophoresis and the distinctions are stressed.2. The phenomenon of "double-focusing", meaning the stationary existence of two lines of the same metal in the presence of two complexing agents (one of which is an amino-poly-acetic acid), offers a possibility for the estimation of yg-and ng-amounts of various metals, incl. Fe3+, Cu2+, Pb2+, Co2+, Y3+, and heavy rare earths. This can not be realized with ordinary ion-exchange nor electrophoresis.3. One of the lines of a double-focus, being located on the acid side of a pHgradient, changes its intensity proportionally to the added amount of a chelating agent (NTA, EDTA, Chel CD). Macro-chelatometry, using external indicators, direct and substitution titrations of metal-traces on a filter-paper strip, are described. The method is more accurate than various micro-chemical procedures. 4. A phenomenological treatment of double-focusing is given.
The macrocyclic compounds IV (n = 4–7) are synthesized by adding toluene solutions of the dianils III under conditions of high dilution to an emulsion of sodium in the same solvent.
The reaction of metallic sodium with phenyl, ethyl and benzyl phenyliminobenzoates has been investigated in an inert solvent. The main products are benzil‐dianil in case of the phenyl derivative, and benzanilide in case of the ethyl and benzyl derivatives. A free radical mechanism is postulated.
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