ADSORPTION OF PRIMARY ALCOHOLS IN CU(II)-DOPED MG(II)-EXCHANGED SMECTITE CLAYS STUDIED BY ELECTRON-SPIN-RESONANCE AND ELECTRON-SPIN ECHO MODULATION

Electron spin resonance (ESR) and electron spin echo modulation (ESEM) have been used to study the adsorption of short chain length primary alcohols in Cu(II)-doped Mg(II)-exchanged synthetic beidellite, fluorohectorite, and hydroxyhectorite layered smectite clays. These results are compared with previous results for the adsorption of alcohols in Cu(II)-doped Mg(II)-exchanged natural montmorillonite. In montmorillonite, Cu(II) cations form square-planar complexes with four molecules of methanol and ethanol in the middle of the interlayer space of the smectite but coordinate with only three propanol molecules. In beidellite, the Cu(II) species are coordinated to only three alcohol molecules and to presumably three oxygen atoms of the interlayer surface. In the two hectorites, only one alcohol molecule directly coordinates to Cu(II) cations which are recessed inside pseudohexagonal cavities bordering the interlayer space.