Water-insoluble, Re-immobilized Liphophilic Ligands and Their Separation by Membrane Technique

Water-insoluble, Re-immobilized Liphophilic Ligands and Their Separation by Membrane Technique 

The water-insoluble ammonium ligands are prepared from available water-soluble sodium salts according to Eq. (1). By introducing different amines in solvents, the sodium cations of the sulfonates can be exchanged in the presence of sulfuric acid. Sodium hydrogensulfate as a by-product can be removed smoothly by phase separation. This re-immobilization technique may also be extremely useful in the separation of salts from raw sulfonation mixtures within the preparation of sulfonated phosphines [12]. According to Eq. (1) many variations are possible, for example in the amines, functionalized phosphorus ligands, acids, solvents, and preparation procedures. The variability of the monoamines is demonstrated in Table 1. 

In all cases the P(III) yield (transition into the organic phase) is sufficient. For amines with higher molecular masses the pH value is generally lower. Perhaps because of the large distance between the amine groups, the multifunctional amines do not tend to polymerize as do the lower amines (see below). 

Entry Amine Mol. mass Temp. [C] pH Start End Addition of /-C3H7OH P(lll) content of phases [%] Lower Upper aqueous organic  

Solvent, 2.7 g toluene/g amine source of phosphorus, TPPTS, 0.33 mol/mol amine acid, sulfuric acid. 

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