Column connexion

Studies of heat economy made by Faldix and Stage [176a] have resulted in optimum column connexions in two-column systems. Flow diagram variants for the multicomponent separation in columns with intermediate take-off were developed by Muller [176b]. 

Billet [176 c] shows that deviations from optimum column lay-out may lead to a drastic increase in cost. The connexion of main and side columns and the use of partial condensation in direct and countercurrent operation, where appropriate are also discussed. These principles should be considered in laboratory and semitechnical work. Comparative studies of the applicability of heuristic rules and approximate methods in the selection of appropriate column connexions for nmlticomponenl countercurrent distillation were made by Jobat et al. [176d]. 

In accordance with a description by Blasius and coworkers a condensation resin was synthesized from phenol and formaldehyde which contains dibenzo[18]crown-6 anchor groups . The structure of this resin can be seen in Fig. 6 in connexion with Fig. 11. The capacity of this resin was determined to be 0.85 mmol/g for the uptake of calcium ions from a methanolic solution of CaClj. 0.052 mmol Cal2 were eluted from a column with a mixture of 30% methanol/70% tetrahydrofuran (v/v) (2.4 g resin, particle size = 45-90 pm). The elution curve is given in Fig. 15 . 

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