The reaction of benzene with exchangeable Cu(II) and Fe(III) in hectorite clay films was studied by electron paramagnetic resonance (EPR). The reaction when carried out in a sealed tube between 60° and 100°C produced a variety of organic radical products. The nature of these products depended on the concentration of water in the reaction medium and the reaction time. The free radicals were accompanied by a reduction in the oxidation state of the metal ions; this process had a zero-order dependence on the metal ion concentration. The activation energies determined from the zero-order rate constants are 67 ± 11 kJ/mole (Cu(II)) and 46 ± 6 kJ/mole (Fe(III)). The free radicals initially formed under anhydrous conditions appeared to populate sites in the interlayer region; the activation energies determined for this first order process are 57 ± 9 kJ/mole (Cu(II)) and 42 ± 3 kJ/mole (Fe(III)). These activation energies are within experimental error of those determined from the metal ion kinetics. The EPR signal due to organic radicals showed little temperature dependence; thus, exchange processes involving organic free radicals were probably not important in determining EPR lineshapes.

Four hydrates with d(001) = 8.4, 8.6, and 10 Å (two types) were synthesized by intercalating kaolinite with dimethylsulfoxide and treating the intercalated clay with fluoride ions. X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, and kinetics of dehydration experiments have led to the identification of two types of interlayer water. One type of water (hole water) is situated in the ditrigonal holes of the silica tetrahedral surface; the second type (associated water) forms a discontinuous layer of mobile water. The 8.4-Å and 8.6-Å hydrates have only hole water, whereas the two synthetic 10-Å hydrates and halloysite(10Å) contain both hole and associated water. The hole water is probably hydrogen bonded to the basal oxygens of the silica tetrahedra or, in the 8-Å hydrates when fluorine exchanges for inner-surface hydroxyls, the water molecules may reorient and form stronger hydrogen bonds to the fluorine. Associated water forms water-water hydrogen bonds approximately equal in strength to liquid water but is less strongly bonded to the clay surfaces than hole water. At room temperature the hole and associated water in the 10-Å hydrates do not form an ice-like structure.