**3.1. Patent literature**

**2.3. London-forces (corkscrew) approach**

128 Column Chromatography

**Figure 2.** Schematic representation of a Dean-Stark Apparatus [21]

On occasion useful ligands are available, but need to be converted to supported ligands.

Examples of such ligands include LIX54 [CH3(CH2)11C6H4COCH2COCH3], LIX860 (*n*-dodecyl‐ saldoximine), oleoylacetone, and *N, N*'-didodecyldithiooxamide (all were once commercially available). A two-step procedure was used [24-27]: First, silica gel (5 g) was mixed with 25 mL of hexane, and the excess solvent allowed to evaporate to produce silica gel with pores loaded with hexane. Next the treated silica gel was mixed with a solution of a chelating agent in hot hexane. After stirring, the hexane was allowed to evaporate. It was hypothesized that a change in environment resulted with the evaporation of the hexane, i.e., that the long-chain hydro‐

Lindoy and Eaglin [14] provided useful information about their experiments demonstrating the efficacy of removal of representative transition metal ions.
