Hydroxyl reaction with inorganic anions

The hydroxyl radical is a powerful oxidant, having a reduction potential of 2.7 V in acidic solution. In neutral solution, where the free energy of neutralization of OH by H3O is not available, the reduction potential decreases to 1.9 V (Table 2). Several inorganic anions and low-valency transition metal ions readily undergo one-electron oxidation by reaction with OH, which is often represented as a simple electron transfer ... 

Different ways to immobilize ILs are described, particularly for chloroaluminate-based ILs (see Section 5.2.1.3). Two preparation procedures can be envisioned. The simplest one is just an impregnation of the chloroaluminate IL to fiU the pores of the dehydrated inorganic solid. The chloroaluminate anion is grafted on the surface by reaction with the surface hydroxyl group. This method may present some disadvantages, such as destruction of the structure of the support and the modification of the acidity of the Lewis acid. 

The anion exchange mechanism in Table 4.3 is the analog of the reaction in Eq. 4.45, wherein the signs of the valences are reversed B symbolizes a carboxylate group (COO ) and M is replaced by a univalent, inorganic anion that forms outer-sphere complexes with protonated surface hydroxyl or amine groups. This mechanism is not observed often, possibly because of the weakness of the surface complexes involved, but it should be prominent in acidic soils whose clay fraction comprises primarily metal oxides. 

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