SOLID-STATE ION-EXCHANGE IN H-SAPO-34 - ELECTRON-SPIN-RESONANCE AND ELECTRON-SPIN ECHO MODULATION STUDIES OF CU(II) LOCATION AND ADSORBATE INTERACTION

The solid-state reactions of H-SAPO-34 with various copper compounds, such as CuO, CuCl2, and CuF2, are examined in this work. Electron spin resonance (ESR) and electron spin echo modulation (ESEM) techniques are employed to study the location of the Cu(II) ion exchanged through a solid-state reaction and the interaction of the Cu(II) ion with water, alcohols, ammonia, and ethylene. The migration of Cu(II) ions from the exterior surface of the molecular sieve into interior cationic positions is observed with the three cupric compounds investigated. The hyperfine splitting of the Cu(II) ion does not vary with the type of copper compound employed. The results of this investigation gave similar results to those found for Cu(II) ion incorporation through an aqueous ion exchange method. The ESR spectra of dehydrated samples exposed to dimethyl sulfoxide, ethylene, ammonia, ethanol, 1-propanol, and water indicate the formation of one type of Cu(II) complex, while the adsorption of methanol influences the formation of two distinct Cu(II) complexes. Through analysis of the ESEM signal it was determined that Cu(II) interacts with one dimethyl sulfoxide molecule, one ethylene molecule, three ethanol molecules, three ammonia molecules, and three water molecules.